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The decline in cognitive function in older adults with mild cognitive impairment (MCI) may contribute to a change in movement pattern during sit-to-stand transitions (STS). However, when comparing older adults with MCI to older adults without MCI, there is a lack of evidence of kinematic and kinetic data during STS. Furthermore, while significant cognitive dual-task interference has been demonstrated in older adults with MCI, studies on the effects of dual motor tasks in MCI, particularly during STS, have not been reported. Are there any differences in the movement time, joint angles, and maximum joint moments while performing STS under single- and dual-task conditions in older adults with and without MCI? In a cross-sectional study, 70 participants were divided into two groups: older adults with MCI and without MCI. Motion analysis and a force plate system were used to collect and analyze the STS movement. All participants were asked to do the STS movement alone and the STS with a dual motor task with the self-selected pattern on an adjustable bench. Older adults with MCI had greater maximum trunk flexion during STS with a dual task than older adults without MCI and greater than STS alone. Furthermore, older adults with MCI had a greater ankle plantar flexion moment during STS with a dual task than during STS alone. Even though the STS task is one of the simplest functional activities, different strategies to achieve the STS action with dual tasks were found among older adults with and without MCI in terms of joint angle and joint moments. • The time used for STS showed no difference between older adults with and without MCI. • STS with dual tasks spent more time to complete than STS alone. • Older adults with MCI perform more trunk flexion during STS with dual tasks. • Older adults with MCI rely on the ankle plantar flexor during STS with dual tasks. [ABSTRACT FROM AUTHOR]

As total ankle arthroplasty (TAA) is an increasingly common surgical intervention for patients with end-stage ankle arthritis, there is a need to better understand the dynamic performance of prosthetic implants during activities of daily living. Our purpose was to quantify and compare relative tibiotalar motion during gait in persons with a fixed-bearing (FB) and mobile-bearing (MB) total ankle arthroplasty. We hypothesized a FB prosthesis would have lower tibiotalar range of motion (ROM). Patients at least 12 months postoperative with either a FB (n=5) or MB (n=3) total ankle arthroplasty were tested. We used high-speed biplanar videoradiography to quantify tibiotalar kinematics during self-selected gait. Angular and linear ROM in three axes were compared between the groups. ROM for dorsiflexion-plantarflexion, internal-external rotation, and inversion-eversion angles in FB subjects averaged 7.47±4.05°, 7.39±3.63°, and 4.51±2.13°, respectively. ROM in MB subjects averaged 6.74±2.04°, 6.28±4.51°, and 5.68±2.81°, respectively. Linear ROM along anteroposterior, mediolateral, and superior-inferior axes in FB subjects averaged 1.47±2.07 mm, 1.13±1.49 mm, and 0.28±0.30 mm, respectively. Linear ROM in MB subjects averaged 0.68±1.44 mm, 0.60±1.41 mm, and 0.20±0.13 mm, respectively. We found no significant difference between the two groups for any of these ROM parameters (p>0.05). Total ankle arthroplasty using either FB or MB design appears to confer similar ankle motion during the gait cycle in this biplanar fluoroscopic model. Level IV, case series. • X-ray motion analysis is a useful tool to compare ankle arthroplasty systems. • No differences in angular motion between MB and FB arthroplasty systems. • No significant difference in linear translation along joint axes in both systems. [ABSTRACT FROM AUTHOR]

Clinical gait analysis (CGA) is a systematic approach to comprehensively evaluate gait patterns, quantify impairments, plan targeted interventions, and evaluate the impact of interventions. However, international standards for CGA are currently lacking, resulting in various national initiatives. Standards are important to ensure safe and effective healthcare practices and to enable evidence-based clinical decision-making, facilitating interoperability, and reimbursement under national healthcare policies. Collaborative clinical and research work between European countries would benefit from common standards. This study aimed to review the current laboratory practices for CGA in Europe. A comprehensive survey was conducted by the European Society for Movement Analysis in Adults and Children (ESMAC), in close collaboration with the European national societies. The survey involved 97 gait laboratories across 16 countries. The survey assessed several aspects related to CGA, including equipment used, data collection, processing, and reporting methods. There was a consensus between laboratories concerning the data collected during CGA. The Conventional Gait Model (CGM) was the most used biomechanical model for calculating kinematics and kinetics. Respondents also reported the use of video recording, 3D motion capture systems, force plates, and surface electromyography. While there was a consensus on the reporting of CGA data, variations were reported in training, documentation, data preprocessing and equipment maintenance practices. The findings of this study will serve as a foundation for the development of standardized guidelines for CGA in Europe. • Survey report on current Clinical Gait Analysis (CGA) practices across Europe. • Good agreement on data included in CGA with video, kinematics, kinetics and EMG. • Training, documentation, maintenance, reliability evaluations vary between laboratories. • New gait analysis tools have limited adoption in CGA. • Results set foundation for a Delphi process to define European CGA standards. [ABSTRACT FROM AUTHOR]

The subtalar joint movement between the talus and calcaneus is restricted in patients with talocalcaneal coalition (TCC). When the motion of the subtalar joint is restricted, shock absorption in the foot decreases, leading to pain during walking. Resection methods to maintain subtalar motion by removing abnormal unions have been proposed. The purpose of this study was to analyze the joint kinematics of patients who underwent TCC resection and to quantitatively evaluate the results of the surgery based on the measured kinematics. Joint kinematics of five patients with TCC were obtained using a biplane fluoroscopic imaging system and an intensity-based two-/three-dimensional registration method. The joint kinematics of the tibiotalar and subtalar joints and the tibiocalcaneal motion during the stance phase of walking were obtained. From the kinematics of the hindfoot joints, the inversion/eversion range of motion (ROM) of the patients before and after resection was statistically analyzed using the Wilcoxon signed-rank test to test whether TCC resection improved the ROM. During the loading response period, the eversion ROM of the subtalar joint and tibiocalcaneal motion significantly increased postoperatively. In addition, a significant postoperative increase was observed in the subtalar and tibiocalcaneal inversion ROM during the pre-swing period. TCC resection surgery increased the ROM of the subtalar joint, which in turn contributed to the increase in tibiocalcaneal ROM. Increased subtalar and tibiocalcaneal ROM could result in increased shock attenuation and may be a contributing factor to pain relief during walking. [ABSTRACT FROM AUTHOR]

Individuals with cerebral palsy (CP) often present with altered motor control. This can be assessed selectively during sitting/lying with the Selective Control Assessment of the Lower Extremity (SCALE), or dynamically with the dynamic motor control index during walking (walk-DMC). Both approaches suggest that altered selective motor control relate to larger gait deviations. Does the walk-DMC provide valuable information in addition to the SCALE for estimating gait deviations in individuals with CP. Retrospective, treadmill-based gait analysis data of 157 children with spastic CP (mean 11.4±3.5 years) and Gross Motor Function Classification System levels I (n=45), II (n=88) or III (n=24) were extracted. Gait kinematic deviations were evaluated using the Gait Profile Score (GPS). The SCALE, walk-DMC and GPS were extracted for the more clinically involved leg (unilateral-analysis), and for both legs together (bilateral-analysis). GPS moderately correlated with both SCALE and walk-DMC scores, unilaterally and bilaterally (r≥0.4; p<0.001). Multivariate linear regression analyses were conducted, taking into account potential confounding factors. In the unilateral analysis, 54% of the GPS variance was explained (p<0.001), with both walk-DMC and SCALE significantly contributing to the GPS variance (p=0.006 and p=0.008, respectively). In the bilateral analysis, 61% of the GPS variance was explained (p<0.001), with both walk-DMC and SCALE significantly contributing to the GPS variance (p=0.006 and p<0.001, respectively). Dimensionless walking speed and use of assistive devices were the only confounding factors included in each analysis. Both SCALE and walk-DMC significantly contribute to GPS variance, suggesting that they likely measure different components of motor control, and both may be useful in understanding the underlying relationship between motor control and deviations in gait kinematics. • Both the SCALE and walk-DMC relate to kinematic gait deviations in CP. • The SCALE and walk-DMC likely measure different components of motor control in CP. • In the absence of EMG, the SCALE can be used to quantify motor control in CP. [ABSTRACT FROM AUTHOR]

Posterior tibialis tendon dysfunction (PTTD) is a chronic degenerative musculoskeletal disorder causing a progressive ankle complex and arch collapse altering lower limb biomechanics. However, biomechanical changes associated with stage 1 and 2 PTTD need to be better characterized during walking to guide clinical recommendations and improve non-operative treatments. What are the lower limb kinematic and kinetic differences between individuals with stage 1 (PTTD1), individuals with stage 2 PTTD (PTTD2) and healthy counterparts during gait? Sixteen PTTD1, 11 PTTD2 and 20 healthy controls were included in this multicentric case-control study to compare their lower limb gait biomechanics. Kinematic and kinetic data were recorded using a three-dimensional motion capture system and a force plate. One-dimensional statistical parametric mapping was used to compare lower limb joint motion and moments between groups during the stance phase. PTTD1 had minimal biomechanical differences compared with the control group. In contrast, PTTD2 presented significant differences compared with controls and PTTD1. At the ankle, PTTD2 exhibited greater plantarflexion and eversion angles and midfoot dorsiflexion and inversion angles throughout stance compared with controls and PTTD1. PTTD2 presented lower midfoot abduction moments compared with controls. These changes led PTTD2 to exhibit knee and hip adaptative biomechanical mechanisms in the frontal and transverse planes in late stance. PTTD2 had greater knee internal rotation angles and smaller knee external rotation moments compared to controls. PTTD2 had smaller hip internal rotation angles compared with PTTD1 and smaller hip adduction moments compared with controls. PTTD1 showed minimal biomechanical differences compared to controls and important differences compared to PTTD2. The lower limb biomechanical deficits accentuate as the pathology advances from stage 1 to stage 2. PTTD is a progressive condition needing early clinical management at stage 1 to avoid successive biomechanical changes associated with stage 2. • PTTD2 presented greater foot and ankle pronation than PTTD1. • Medial longitudinal arch was more collapsed for PTTD2 than PTTD1. • PTTD2 exhibited greater midfoot dorsiflexion/inversion and ankle plantarflexion/eversion. • The lower limbs' biomechanics was similar between PTTD1 and controls. [ABSTRACT FROM AUTHOR]

Trendelenburg gait describes contralateral pelvic drop during single leg stance (SLS) with occasional lateral trunk lean compensation over the stance limb. However, quantitative research on 'uncompensated Trendelenburg' gait (pelvic drop independent of lateral trunk lean) remains sparse among populations that commonly utilize this gait pattern, such as adolescent hip pathology patients. How prevalent is uncompensated Trendelenburg among various adolescent hip pathologies and how is it related to hip load, hip abduction strength, and self-reported hip pain? Gait, strength, and pain data were collected among 152 pre-operative patients clinically diagnosed with acetabular hip dysplasia, femoroacetabular impingement, Legg-Calvé-Perthes, or slipped capital femoral epiphysis (SCFE). Patients with ≥ 5.4° of dynamic pelvic drop in SLS were divided into a 'pelvic drop' group and screened to exclude those with excessive ipsilateral trunk lean. They were then compared to the 'stable pelvis' patients using a Mann-Whitney test. Dysplasia patients represented the highest proportion of the pelvic drop group (46%). The pelvic drop group showed a significant increase in self-reported hip pain (p = 0.011), maximum hip abductor moment (p = 0.002), and peak coronal power absorption at the affected hip during SLS loading response, (p < 0.001) while showing no difference in abduction strength (p = 0.381). Uncompensated Trendelenburg gait may lead to increased loading of the affected hip in adolescent hip pathology patients. Disadvantageous hip biomechanics can create increased abductor muscle demand among these pathological populations, with dysplasia patients showing the highest prevalence. Maximal abduction strength did not correlate with pelvic drop. Future work should aim to identify and quantify causal factors. Increased coronal hip power absorption during weight acceptance warrants clinical attention, as there may be a detrimental, over-reliance on passive hip structures to support load among a population that that is already predisposed to hip osteoarthritis. • Excessive pelvic drop in gait can be exhibited by adolescents with hip disorders. • Without a trunk lean compensation, this gait increases load at the affected hip. • Abnormal hip morphology may create mechanical disadvantages that cannot be overcome. • There may be an over-reliance on passive hip structures to support load. • In populations predisposed to hip osteoarthritis, clinical awareness is warranted. [ABSTRACT FROM AUTHOR]

Hallux Rigidus is the result of degeneration of the 1st metatarsophalangeal joint (1st MTPJ). In end-stage hallux rigidus, treatment is mainly surgical with arthrodesis being a favourable option. Although the biomechanical effects of arthrodesis have been examined, a detailed comparison of pre- and post-operative biomechanics has yet to be conducted. Does 1st MTPJ arthrodesis positively affect foot kinematics and plantar pressure distribution? Twelve 1st MTPJ arthrodesis were performed in patients with a mean age of 53.5 ± 5.4 years and follow up time of 6.9 ± 1.0 months. Pre- and post-operative data were collected at a CMAS (Clinical Movement Analysis Society) accredited gait laboratory using a BTS motion capture system and pedobarographic pressure plates. Patient outcome measures were also assessed using the MOXFQ. Statistical analysis was conducted using a two-way repeated measures ANOVA. Significant changes in stride length, cycle duration, cadence and velocity were identified following 1st MTPJ arthrodesis. A significant reduction in forefoot-hallux dorsiflexion at toe-off was identified for the operated foot from the pre-operative (20.23 ± 5.98°) to post-operative (7.56 ± 2.96°) assessment. Post-operative sagittal and transverse plane changes in the operated foot were also identified. Peak pressure and PTI results indicated significant lateralisation of load for the operated foot, but importantly this was not influenced following arthrodesis. Finally, there was a significant improvement in MOXFQ score. Following 1st MTPJ fusion there is an improvement in overall gait mechanics which accompanied by the improved MOXFQ score indicates a reduction in pain and improved confidence during gait. The lack of post-operative dorsiflexion at forefoot-hallux caused load to remain lateralised and compensatory mechanisms to occur at the more proximal joints within the foot. These results provide valuable information for clinicians and will enable more accurate counselling to be provided to patients with end-stage hallux rigidus. • Stride length, cycle duration and cadence significantly increased. • There was an improvement in the patient reported outcome. • Forefoot-hallux dorsiflexion for the operated foot significantly reduced at toe-off for the operated foot. • Load remains weighed on the lateral aspect of the foot. • Compensatory kinematic mechanics occur at more proximal joints within the foot. [ABSTRACT FROM AUTHOR]

To study the body posture characteristics when walking with trolley case, and to explore the effects of different usage methods and weights of trolley case on body posture characteristics. Fifteen subjects pushed and pulled(Condition 1 and 2) the case with three load weights of 10 %, 20 % and 30 % of their own body weight with 0 % no load as baseline for both conditions. The basic gait parameters, kinematic and kinetic data were collected using the VICON infrared motion capture system and a 3D force platform. Two repeated measures factor (condition×weight) analysis of variance was used for statistical analysis of the gait temporal and spatial parameters, as well as trunk angle, kinetic ground reaction force, shoulder joint force, and trunk moment. Significant condition*weight interactions were detected in DLST (Double Limb Stance Time) (F=5.341，P = 0.006), GRF (Ground Reaction Force) in frontal plane (F=10.507, p < 0.001) and vertical plane (F=3.751, p = 0.021), shoulder joint force in sagittal plane (F=21.129, p < 0.001), and flexion-extension angle of the trunk in the sagittal plane (F=4.888, p < 0.010). Significant main effects were detected in walking speed (F=35.842, p < 0.001), right support time (F=12.156, p < 0.001), left swing time (F=8.506, p < 0.001), left support time (F=1.122, p < 0.001), right step length (F=33.900, p < 0.001), and left step length (F=14.960, p < 0.001) under different weights. A significant main effect was detected in sagittal GRF (F=11.77, p < 0.001), trunk rotation angle (F=4.124, p = 0.016), amplitude of COM (F=2.993, p = 0.046), under different weights. When the weight of the case exceeds 20 % of the body weight, from the perspective of energy efficiency, the push method is more advantageous than the pull method. When walking with luggage, people tend to maintain the stability of their trunk posture by adjusting the force on their arms more often. • To explore the effects of Trolley Case on body posture characteristics. • Adopt two methods and three kinds of weight control trolley. • VICON and three-dimensional dynamometer measure the basic parameters. • Changes in body posture parameters vary across different Trolley Case usage methods. • It is recommended to use the side push mode and 20 % body weight control trolley. [ABSTRACT FROM AUTHOR]

Perinatal running participation has increased recently; however, pregnancy related symptoms can limit activity. Perinatal running biomechanics could inform interventions to help perinatal individuals maintain an active lifestyle. Are perinatal running biomaechanics and muscle activation different compared to nulligravida females? Sixteen pregnant participants completed self-selected velocity running during second trimester (2 T), third trimester (3 T), and postpartum (PP) and 16 matched controls completed these procedures once in this case control study. Kinematic, kinetic, and electromyography (EMG) data were collected using a motion capture system, force plates, and EMG electrodes. Peak trunk, pelvis, hip, knee, and ankle kinematics and hip, knee, and ankle moments during stance phase, and average and peak erector spinae (ES), gluteus maximus (GMax), and gluteus medius (GMed) EMG amplitude and duration of activation during stance and swing phases were calculated. Independent t-tests were used to compare 2 T, 3 T, and PP to control participants (α < 0.05). Running velocity was slower during 3 T compared to control participants. At all pregnancy timepoints compared to the control group, peak trunk contralateral rotation was smaller. During 2 T and 3 T peak hip flexor moments were smaller. At 3 T pelvis contralateral rotation was smaller, ES average amplitude was greater during swing, GMax percent duration during stance and GMed percent duration during swing were smaller. At PP trunk flexion was smaller and knee abduction was greater (all p < 0.05). Decreased running velocity may help offset increased demand during pregnancy. During 3 T, greater ES activation, smaller trunk and pelvis motion, and altered gluteal activation could indicate trunk rigidity combined with modified hip stabilizer muscle utilization. During PP, the rigid trunk combined with greater knee abduction may indicate hip and trunk strength deficits. Altered trunk and hip motion and activation could be relevant to pathologies such as perinatal low back, pelvic girdle, or knee pain. • Decreased trunk rotation was observed during and after pregnancy with running. • Increased trunk activity and decreased gluteal muscle duration were observed during pregnancy. • During third trimester slower running may decrease joint and muscle demand. • Postpartum runners demonstrated an upright trunk and increased knee abduction. [ABSTRACT FROM AUTHOR]

Exploring the use of minimum marker sets is important for balancing the technical quality of motion capture with challenging data collection environments and protocols. While minimum marker sets have been demonstrated to be appropriate for evaluation of some motion patterns, there is limited evidence to support model choices for abrupt, asymmetrical, non-cyclic motion such as balance disturbance during a bathtub exit task. How effective are six models of reduced complexity for the estimation of centre of mass (COM) displacement and velocity, relative to a full-body model. Eight participants completed a bathtub exit task. Participants received a balance perturbation as they crossed the bathtub rim, stepping from a soapy wet bathtub to a dry floor. Six reduced models were developed from the full, 72-marker, 12 segment 3D kinematic data set. Peak displacement and velocity of the body COM, and RMSE (relative to the full-body model) for displacement and velocity of the body COM were determined for each model. Main effects were observed for peak right, left, anterior, posterior, upwards and downwards motion, and peak left, anterior, posterior, upwards and downwards velocity. Time-varying (RMSE) was smaller for models including the thighs than models not containing the thighs. In contrast, inclusion of upper arm, forearm, and hand segments did not improve model performance. The model containing the sacrum marker only consistently performed the worst across peak and RMSE metrics. Findings suggest a simplified centre of mass model may adequately capture abrupt, asymmetrical, non-cyclic tasks, such as balance disturbance recovery during obstacle crossing. A reduced kinematic model should include the thighs, trunk and pelvis segments, although models that are more complex are recommended, depending on the metrics of interest. • Participants were perturbed as they stepped from a soapy wet bathtub to a dry floor. • Six reduced models were compared against a 12-segment full-body model. • A simplified centre of mass model may capture abrupt, asymmetrical, non-cyclic tasks. • A reduced kinematic model should include the thighs, trunk and pelvis segments. [ABSTRACT FROM AUTHOR]

It has been suggested that sitting posture affects clavicular, scapular and spinal kinematics, however its effects in people with neck pain and scapular dysfunction remain unknown. The study aimed to determine the clavicular and scapular kinematics in different sitting postures in patients with neck pain and scapular dysfunction. Thirty-four participants with neck pain and scapular dysfunction were recruited into the study. Kinematics of the clavicle and scapula were recorded using motion analysis at rest and during arm elevation (at 30, 60, 90, and 120 degrees) in a slouched and upright sitting posture. Compared to the upright sitting posture, the slouched sitting posture had increased clavicular protraction and elevation as well as scapular internal rotation and anterior tilt at rest and during the arm raising and lowering phases (at 30, 60, 90, and 120 degrees) (p < 0.05). The slouched sitting also had increased scapular upward rotation in the lowering phase at all angles (p < 0.05). The slouched sitting posture has a significant influence on clavicular and scapular kinematics. Awareness of good sitting posture should be encouraged in patients with neck pain and scapular dysfunction. • Slouched sitting alters the clavicular and scapular orientations and movements. • Patients with neck pain tend to protract shoulder girdle in slouched sitting. • Side of neck pain has no influence on clavicular and scapular positions in sitting. [ABSTRACT FROM AUTHOR]

Prosthetic foot stiffness, which is typically invariable for commercially available prosthetic feet, needs to be considered when prescribing a prosthetic foot. While a biological foot adapts its function according to the movement task, an individual with lower limb amputation may be limited during more functionally demanding gait tasks by their conventional energy storing and return prosthetic foot. How do changes in prosthetic foot stiffness during incline walking affect biomechanical measures as well as perception of participants. Kinetic and kinematic data were collected during incline walking, for five participants with trans-tibial amputation. A mixed model analysis of variance was used to analyse the effects of changing the stiffness during incline walking, using a novel variable-stiffness unit built on a commercially available prosthetic foot. Biomechanical results were also analysed on an individual level alongside the participant feedback, for a better understanding of the various strategies and perceptions exhibited during incline walking. Statistically significant effects were only observed on the biomechanical parameters directly related to prosthetic ankle kinematics and kinetics (i.e., peak prosthetic ankle dorsiflexion, peak prosthetic ankle power, dynamic joint stiffness during controlled dorsiflexion). Participant perception during walking was affected by changes in stiffness. Individual analyses revealed varied perceptions and varied biomechanical responses among participants. While changes in prosthesis mechanical properties influenced the amputee's experience, minimal immediate effects were found with the overall gait pattern. The reported inter-participant variability may be due to the person's physical characteristics or habitual gait pattern, which may influence prosthesis function. The ability to vary prosthetic foot stiffness during the assessment phase of setting up a prosthesis could provide useful information to guide selection of the appropriate prosthetic device for acceptable performance across a range of activities. • Individuals exhibit different gait patterns which may influence prosthetic preference. • Variability in prosthetic foot stiffness perception and preference was reported. • Providing an option of varying stiffness during different gait tasks may benefit the user. [ABSTRACT FROM AUTHOR]

Inertial Measurement Units (IMUs) offer a promising alternative to optoelectronic systems to obtain joint lower-limb kinematics during gait. However, the associated methodologies, such as sensor-to-segment (S2S) calibration and multibody optimization, have been developed mainly for, and tested on, asymptomatic subjects. This study proposes to evaluate two personalizations of the methodology used to obtain lower-body kinematics from IMUs with pathological subjects: S2S calibration and multibody optimization. Based on previous studies, two decision trees were developed to select the best (in terms of accuracy and repeatability) S2S methods to be performed by the patient given his/her abilities. The multibody optimization was personalized by limiting the kinematic chain range of motion to the results of the subject's clinical examination. These two propositions were tested on 12 patients with various gait deficits. The patients were equipped with IMUs and reflective markers tracked by an optoelectronic system. They had to perform the postures and movements selected by the decision trees then walk back and forth along a walkway. Gait kinematics obtained from the IMUs directly (referred to as Direct kinematics), and after multibody optimization performed via the OpenSim software using the generic range of motion (referred to as Generic Optimized kinematics), and using the personalized range of motion (referred to as Personalized Optimized kinematics) were compared to those obtained with the Conventional Gait Model through Root Mean Square Errors (RMSE), Correlation Coefficients (CC) and Range of Motion differences (ΔROM). The RMSEs were smaller than 8.1° in the sagittal plane but greater than 7.4° in the transverse plane. The CCs, between 0.71 and 0.99 in the sagittal plane, deteriorate sharply in the frontal and transverse planes where they only measured between 0.15 and 0.68. The ΔROMs were mostly below 8.3°. Optimized kinematics did not improve compared to Direct kinematics. The personalization of the proposed S2S calibration method showed encouraging results, whereas multibody optimization did not impact the resulting joint kinematics. • Decision trees were built to select the most appropriate S2S calibration. • The kinematic chain RoM was limited to the results of the clinical examination. • The results were similar to those obtain with asymptomatic subjects. • Multibody optimization personalization had no noticeable impact on the kinematics. [ABSTRACT FROM AUTHOR]

Patients with cerebral palsy and increased femoral anteversion frequently show disturbing internal rotation gait which may be treated via femoral derotation osteotomy (FDO). A recent study monitored that hip rotation in gait may heavily depend on the procedure by which it is being determined. Traditional measures using the femoral epicondyles as reference for the knee axis (CONV) resulted in more severe transverse plane deviations compared to those using a functional method (FUNC) with relevant implications for treatment indication of FDO. Is mean hip rotation in stance (mHipRotSt) as obtained via FUNC the more sensitive measure for explaining functional changes after FDO compared to CONV method taking the femoral epicondyles as reference for the knee axis? 3D-gait analysis before and one year after FDO was performed in fourteen patients including functional joint axis determination of the knee of which MR imaging was available in eight patients both pre- and postoperatively. Transverse plane gait parameters were calculated using both approaches (CONV, FUNC). Differences between examinations as well as between methods were determined. Changes in femoral anteversion as measured by MR reasonably well confirm the structural changes as measured clinically and intraoperatively. The average change in mHipRotSt across the group was substantially smaller than the structural change implies. Further, using the FUNC approach led to much smaller values compared to when using the CONV approach. We address this to a mismatch between the axes determined in each method. In the presence of femoral deformity, the knee joint axis as determined via a functional method together with the conventional method (femoral epicondyles for the knee axis) allows to quantify knee rotation independent of torsional parameters of the tibia. It may therefore help to better quantify rotational malalignments in gait and improve decision making of FDO. • Gait and MRI before and after femoral derotation osteotomy is monitored in CP. • Conventional and functional method was applied for knee axis determination. • Structural changes measured clinically match surgery reports and findings with MRI. • Hip rotation largely differed between methods for knee axis determination. • The functional approach complements the conventional for quantifying knee rotation. [ABSTRACT FROM AUTHOR]

The effect of Deep Brain Stimulation (DBS) on gait in Parkinson's Disease (PD) is poorly understood. Kinematic studies utilizing quantitative gait outcomes such as speed, cadence, and stride length have shown mixed results and were done mostly before and after acute DBS discontinuation. To examine longitudinal changes in kinematic gait outcomes before and after DBS surgery. We retrospectively assessed changes in quantitative gait outcomes via motion capture in 22 PD patients before and after subthalamic (STN) or globus pallidus internus (GPi) DBS, in on medication state. Associations between gait outcomes and clinical variables were also assessed. Gait speed reduced from 110.7 ± 21.3 cm/s before surgery to 93.6 ± 24.9 after surgery (7.7 ± 2.9 months post-surgery, duration between assessments was 15.0 ± 3.8 months). Cadence, step length, stride length, and single support time reduced, while total support time, and initial double support time increased. Despite this, there was overall improvement in the Movement Disorder Society-Unified Parkinson Disease Rating Scale-Part III score "on medication/on stimulation" score (from 19.8 ± 10.7–13.9 ± 8.6). Change of gait speed was not related to changes in levodopa dosage, disease duration, unilateral vs bilateral stimulation, or target nucleus. Quantitative gait outcomes in on medication state worsened after chronic DBS therapy despite improvement in other clinical outcomes. Whether these changes reflect the effects of DBS as opposed to ongoing disease progression is unknown. ● Kinematic gait parameters in Parkinson's disease change after deep brain stimulation. ● Gait velocity decreases despite improvement in motor function. ● Gait velocity change did not correlate with levodopa dose reduction. [ABSTRACT FROM AUTHOR]

Stabilisation of the centre of mass (COM) trajectory is thought to be important during running. There is emerging evidence of the importance of leg length and angle regulation during running, which could contribute to stability in the COM trajectory The present study aimed to understand if leg length and angle stabilises the vertical and anterior-posterior (AP) COM displacements, and if the stability alters with running speeds. Data for this study came from an open-source treadmill running dataset (n = 28). Leg length (m) was calculated by taking the resultant distance of the two-dimensional sagittal plane leg vector (from pelvis segment to centre of pressure). Leg angle was defined by the angle subtended between the leg vector and the horizontal surface. Leg length and angle were scaled to a standard deviation of one. Uncontrolled manifold analysis (UCM) was used to provide an index of motor abundance (IMA) in the stabilisation of the vertical and AP COM displacement. IMA AP and IMA vertical were largely destabilising and always stabilising, respectively. As speed increased, the peak destabilising effect on IMA AP increased from −0.66(0.18) at 2.5 m/s to −1.12(0.18) at 4.5 m/s, and the peak stabilising effect on IMA vertical increased from 0.69 (0.19) at 2.5 m/s to 1.18 (0.18) at 4.5 m/s. Two simple parameters from a simple spring-mass model, leg length and angle, can explain the control behind running. The variability in leg length and angle helped stabilise the vertical COM, whilst maintaining constant running speed may rely more on inter-limb variation to adjust the horizontal COM accelerations. • Centre of mass (COM) stabilisation is thought to be important during running. • Peak stabilisation of vertical COM occurred at initial contact and toe-off. • Stabilisation of vertical COM increased with increasing running speed. • Stabilisation of vertical COM was anti-phase with anterior-posterior COM. • Two simple parameters, leg length and angle, can explain running control of COM. [ABSTRACT FROM AUTHOR]

Repetitive impacts during running are associated with some running injuries. Tibial acceleration is a proxy for tibial loading, and interventions that can decrease it are likely to be of interest to the running community. What effect do running gait cues have on peak vertical tibial acceleration at a comfortable and moderate running pace, and how will these cues be executed? Twenty-seven participants ran on a treadmill according to the following cues in random order: run softly and lightly, run with shorter steps, and increase preferred step rate by 7.5 %. Participants maintained each condition for one minute before returning to their 'preferred' running pattern for two minutes. Two tibia-mounted inertial measurement unit sensors were used to collect tibial acceleration data at a 'comfortable' and 'moderate' run pace. A repeated measures analysis of variance test was used to compare the means between running conditions. Compared to preferred running, the decrease step length (−8 %, p = 0.002, Cohen's d =0.33) and run softly and lightly (−9 %, p = 0.040, Cohen's d =0.38) cues provided a significant reduction in peak vertical tibial acceleration during a comfortable run pace. No significant difference was observed with an increase in step rate. Compared to preferred running, there was no significant difference in peak vertical tibial acceleration with any of the running gait cues during a moderate run pace. Instructing runners to decrease step length or run softly and lightly can result in small reductions in peak vertical tibial acceleration during a comfortable run pace, but running gait cues during a moderate run pace provide no effects. Differences in the execution of each cue are likely to influence overall tibial loading throughout the stride cycle. These findings provide novel biomechanical evidence for the potential effects of running retraining strategies for reducing tibial accelerations at different running paces. • Running gait cues can be effective in reducing tibial loads at a comfortable pace. • Using gait cues to reduce tibial loads at a moderate pace is more of a challenge. • Cues to increase step rate and decrease step length do not provide the same effect. [ABSTRACT FROM AUTHOR]

Individuals with highly pronated feet (PF) are more prone to lower extremity injuries than those with mildly PF. However, whether foot kinematics and ground reaction force (GRF) characteristics differ according to the severity of PF deformity is unclear. Are there differences in foot kinematics and GRF characteristics during walking between individuals with mildly PF and those with highly PF? Ten individuals with mildly PF and 10 with highly PF (six-item foot posture index scores: 6–9 and 10–12 points, respectively) participated in this study. A three-dimensional motion analysis system measured participants' foot kinematics and GRF characteristics during gait trials. Participants with highly PF exhibited significantly lower medial longitudinal arch heights than those with mildly PF from 0 % to 90 % of the stance phase (p < 0.05). No significant differences were observed in any of the angles between the foot segments. Additionally, participants with highly PF exhibited significantly larger posterior GRF than those with mildly PF from 2 % to 7 % of the stance phase (p < 0.05). Participants with highly PF also exhibited significantly larger anterior GRF than those with mildly PF, from 62 % to 82 % of the stance phase (p < 0.05). The results of this study suggest that the more severe the PF deformity, the more inefficient the foot ground force transmission, and the stronger the load applied to the foot. These results may be related to the higher incidence of lower extremity injuries in individuals with highly PF than in those with mildly PF. • Highly pronated feet (PF) are more prone to lower extremity injury than mildly PF. • We examined foot kinematics and ground reaction force characteristics when walking. • Highly PF showed lower medial longitudinal arch heights than mildly PF. • Highly PF exhibited a larger anteroposterior ground reaction force than mildly PF. • A stronger impact may be related to the higher injury incidence with highly PF. [ABSTRACT FROM AUTHOR]

Trunk muscle activity and thoraco-lumbar kinematics can discriminate between non-specific chronic low back pain (NSCLBP) subgroups and healthy controls. However, research commonly focuses on lumbar kinematics, with limited understanding of relationships between kinematics and muscle activity across clinical subgroups. Similarly, the thoracic spine, whilst intuitively associated with NSCLBP, has received less attention and potential relationships between spinal regions and muscle activity requires exploration. Is there a relationship between trunk muscle activation and regional thoracic and lumbar kinematics in NSCLBP subgroups during a forward bending task? Observational, case-control study. Fifty subgrouped NSCLBP motor control impairment participants (27 Flexion Pattern (FP-MCI), 23 Active Extension Pattern (AEP-MCI)) and 28 pain-free controls were evaluated using 3D motion analysis (Vicon™) and surface electromyography during a forward bending and return to upright task. Mean sagittal angles for the upper-thoracic (UTx), lower-thoracic (LTx), upper-lumbar (ULx) and lower-lumbar (LLx) regions were compared with normalised (% sub-maximal voluntary contraction) mean amplitude electromyography of bilateral transversus abdominis/internal oblique, external oblique, superficial lumbar multifidus and erector spinae (longissimus thoracis) muscles between groups. Pearson correlations were computed to assess relationships (significance p < 0.01). AEP-MCI individuals demonstrated statistically significant relationships between superficial lumbar multifidus and ULx and LLx kinematics (−.812 to.659). FP-MCI individuals exhibited statistically significant relationships between erector spinae and superficial lumbar multifidus and LLx and LTx kinematics (−.686 to.664) in both task phases, and between external oblique and LTx during forward bending) (−.459 to.572). Correlations were moderate to strong for all significant relationships (−.812 to.664). Relationships between muscle activity and regional spinal kinematics varied between NSCLBP subgroups, suggesting that those with flexion- or extension-related LBP adopt different motor control strategies when performing a bending task. As effectively mechanical biomarkers, these findings may inform treatment by improving understanding of varied motor strategies in subgroups. • Relationships between muscle activity and spinal kinematics vary in LBP subgroups. • Varied compensatory spinal behaviours indicate that regional insights are important. • As potential biomarkers, this could help personalise rehabilitation approaches. [ABSTRACT FROM AUTHOR]

The longitudinal arch of the foot acts like a spring during stance and contributes to walking efficiency. Pronated foot characterized by a collapsed medial longitudinal arch may have the impaired spring-like function and poor walking efficiency. However, the differences in the energetic behavior during walking between individuals with pronated foot and neutral foot have not been considered. How does the energetic behavior within the foot and proximal lower limb joints in pronated foot affect walking efficiency? Twenty-one healthy young adults were classified into neutral foot and pronated foot based on the Foot Posture Index score. All subjects walked across the floor and attempted to have the rearfoot and forefoot segments contact separate force plates to analyze the forces acting on isolated regions within the foot. Kinematic and kinetic data were recorded by a three-dimensional motion capture system. The hip, knee, ankle, and mid-tarsal joint power was quantified using a 6-degree-of-freedom joint power method. To qualify total power within all structures of the foot and forefoot, we used a unified deformable segment analysis. Additionally, we calculated the center of mass power to quantify the total power of the whole body There is no difference in the mid-tarsal joint work between the pronated foot and neutral foot. On the other hand, pronated foot exhibited greater net negative work at structures distal to the forefoot during walking. Additionally, pronated foot exhibited less net positive work at the ankle and center of mass during walking compared to neutral foot. Individuals with pronated foot generate the mid-tarsal joint work by increasing the work absorbed at structures distal to the forefoot, which results in reduced energy efficiency during walking. That energy inefficiency may reduce positive work at the ankle and affect the walking efficiency in individuals with pronated foot. • We investigated the energetic behavior during walking in neutral and pronated foot. • There is no difference in the mid-tarsal joint work between groups. • Pronated foot had greater negative work at distal to forefoot and rearfoot. • Pronated foot had less positive work at the ankle and center of mass. • Energy loss at the foot affects ankle work and walking efficiency in pronated foot. [ABSTRACT FROM AUTHOR]

Local dynamic stability (LDS) has become accepted as a gait stability indicator. The deterioration of gait stability is magnified in older adults. What is the current state in the field regarding rthe relationship between LDS and cognitive and/or physical function in older adults? A scoping review design was used to search for peer-reviewed literature or conference proceedings published through May 2023 for an association between LDS and cognitive (e.g., Montreal Cognitive Assessment) or physical performance (e.g., Timed Up & Go Test) in older adults. Only studies investigating gait stability via LDS during controlled walking, when dealing with a subject group consisting of healthy older adults, and quantifying LDS relationship to cognitive and/or physical measure were included. We analysed data from the studies in a descriptive manner. In total, 814 potentially relevant articles were selected, of which 15 met the inclusion criteria. We identified 37 LDS quantifiers employed in LDS-cognition and/or LDS-physical performance relationship assessment. Nine measures of cognitive and 20 measures of physical performance were analysed. Most studies estimated LDS quantities using triaxial acceleration data. However, there was a variance in sensor placement and signal direction. Out of the 56 studied relationships of LDS to physical performance measures, sixteen were found to be relevant. Out of 22 studied relationships between LDS and cognitive measures, only two were worthwhile. Considering the heterogeneity of the utilized LDS (caused by different sensors locations, signals, and signal directions as well as variety of computational approaches to estimate LDS) and cognitive/physical measures, the results of this scoping review does not indicate a current need for a systematic review with meta-analysis. To assess the overall utility of LDS to reveal a relationship between LDS to cognitive and physical performance measures, an analysis of other subject groups would be appropriate. • Stable gait in older adults is important in various contexts. • Fifteen studies were included in this review. • The analysed kinematic signals were varied, but mainly included acceleration. • Out of 9 tested cognitive measures, only MMSE showed a significant relationship to LDS. • The relationship of LDS to most physical performance measures is poor. [ABSTRACT FROM AUTHOR]

Dyskinetic cerebral palsy (DCP) is clinically characterized by involuntary movements and abnormal postures, which can aggravate with activity. While upper limb movement variability is often detected in the clinical picture, it remains unknown how movement patterns of individuals with DCP differ from typically developing (TD) peers. Do individuals with DCP show i) higher time-dependent standard deviations of upper limb joint angles and ii) altered upper limb kinematics in time and/or amplitude during functional upper limb tasks in comparison with TD individuals? Three-dimensional upper limb movement patterns were cross-sectionally compared in 50 individuals with and without DCP during three functional tasks: reach forward (RF), reach and grasp vertical (RGV) and reach sideways (RS). Mean and point-wise standard deviations of angular waveform of the upper limb joint angles were compared between groups to evaluate differences in time and/or amplitude using traditional and non-linear registration statistical parametric mapping. Thirty-five extremities from 30 individuals (mean age 17y4m, range 5–25 y; MACS level I(n = 2); II(n = 15); III(n = 16); IV(n = 2)) with DCP and twenty TD individuals (mean age 16y8m, range 8–25 y) were evaluated. The DCP compared to TD group showed higher point-wise standard deviations at the level of all joints, which was time-dependent and varied between tasks. Mean wrist and elbow flexion was higher for the DCP group during RF (0–83 % wrist; 57–100 % elbow), RGV (0–82 % wrist; 12–100 % elbow) and RS (0–43 % wrist; 70–100 % elbow). This is the first study exploring the movement patterns of individuals with DCP during reaching using quantitative measures. Analyzing these individual movement patterns by statistical parametric mapping (SPM) allows us to focus on both specific joint or on specific timing during the movement cycle. The individual information that this method yields can guide individual therapy aiming to improve reaching function in different parts of the movement cycle or evaluate intervention effects on upper extremity treatment. • We explored the variability of 3D upper limb waveforms in dyskinetic CP (DCP) with statistical parametric mapping (SPM). • This is the first study using non-linear registration SPM in 3D upper limb movements. • The DCP compared to typically developing group showed higher, task-dependent point-wise standard deviations in all tasks. • The DCP compared to typically developing group showed higher wrist/elbow flexion in the majority of the reaching cycle. [ABSTRACT FROM AUTHOR]

Adolescents undergo a period of motor incoordination during puberty characterized by high movement variability. It is unknown if differences in running kinematics variability exist among adolescent long-distance runners. Is kinematic variability different among male and female adolescent long-distance runners of different stages of physical maturation? We enrolled 114 adolescent long-distance runners (ages 8–19, F = 55, M = 59) in this secondary analysis of a larger cross-sectional study. Participants completed a three-dimensional overground running analysis at a comfortable self-selected speed. Peak frontal, sagittal, and transverse plane hip, knee, and ankle/shoe joint angles from the right leg were identified during stance phase for at least five trials. Variability in running kinematics was quantified as the standard deviation of the peak joint angles among the running trials for each participant. Participants were stratified by sex and stage of physical maturation (pre-, mid-, post-pubertal) and two-way ANOVAs compared between-subjects variability among groups (p ≤.05). Significant sex by maturation interactions were observed for hip external rotation and ankle external rotation variability. Sex differences were observed for hip internal rotation, with males demonstrating greater variability, and ankle internal rotation, with females demonstrating greater variability. Pre-pubertal runners demonstrated significantly greater variability than mid-pubertal runners for hip flexion, and greater variability than post-pubertal runners for hip flexion, hip adduction, hip internal rotation, and knee flexion. Pre-pubertal adolescent long-distance runners demonstrate greater stance phase variability in running kinematics than post-pubertal adolescent long-distance runners, while adolescent males and females demonstrate similar variability. Anthropometric and neuromuscular changes that occur during puberty likely influence running patterns and may contribute to more consistent kinematic patterns for post-pubertal runners. • Pre-pubertal runners demonstrate greater kinematic variability than post-pubertal runners. • Kinematic variability generally decreased as runners progressed from pre- to post-pubertal status. • Male and female runners demonstrate similar kinematic variability. [ABSTRACT FROM AUTHOR]

Balance impairments are common in children with cerebral palsy (CP). Muscle activity during perturbed standing is higher in children with CP than in typically developing (TD) children, but we know surprisingly little about how sensorimotor processes for balance control are altered in CP. Sensorimotor processing refers to how the nervous system translates incoming sensory information about body motion into motor commands to activate muscles. In healthy adults, muscle activity in response to backward support-surface translations during standing can be reconstructed by center of mass (CoM) feedback, i.e., by a linear combination of delayed (due to neural transmission times) CoM displacement, velocity, and acceleration. The level of muscle activity in relation to changes in CoM kinematics, i.e., the feedback gains, provides a metric of the sensitivity of the muscle response to CoM perturbations. Can CoM feedback explain reactive muscle activity in children with CP, yet with higher feedback gains than in TD children? We perturbed standing balance by backward support-surface translations of different magnitudes in 20 children with CP and 20 age-matched TD children and investigated CoM feedback pathways underlying reactive muscle activity in the triceps surae and tibialis anterior. Reactive muscle activity could be reconstructed by delayed feedback of CoM kinematics and hence similar sensorimotor pathways might underlie balance control in children with CP and TD children. However, sensitivities of both agonistic and antagonistic muscle activity to CoM displacement and velocity were higher in children with CP than in TD children. The increased sensitivity of balance correcting responses to CoM movement might explain the stiffer kinematic response, i.e., smaller CoM movement, observed in children with CP. The sensorimotor model used here provided unique insights into how CP affects neural processing underlying balance control. Sensorimotor sensitivities might be a useful metric to diagnose balance impairments. • Sensorimotor models yield insight into neural processes that control balance. • Center of mass feedback pathways might underlie balance control in CP. • Muscle activation in response to center of mass perturbations was increased in CP. • Increased sensitivity to CoM displacement and velocity impairs balance control. • Sensorimotor sensitivities might be a useful metric to diagnose balance impairments. [ABSTRACT FROM AUTHOR]

Individuals with Chronic Ankle Instability (CAI) demonstrate altered gait mechanics, impaired proprioception, and decreased postural control. In addition, individuals with CAI have been found to have complex neurophysiological changes, including during dual-task perturbations. However, the results of studies on whether cognitive tasks affect postural control are inconclusive. Do individuals with CAI have worse dual-task performance compared to healthy controls? We searched 4 electronic databases (PubMed, MEDLINE, Cumulative Index of Nursing and Allied Health Literature, and SPORTDiscus) from inception to October 2022. Search terms consisted of: ("dual-task*" OR "dual task*" OR dual-task OR Multitask* OR Multi-task* OR attention OR cognit*) AND (balance OR "postural control" OR "postural sway" OR kinetics OR kinematics OR gait) NOT (concussion OR "traumatic brain injury") combined using the operator "AND" ("ankle sprain" OR "ankle instability" OR CAI). Studies were included if the physical task was postural control or gait, and if they compared control and CAI groups. A total of 9 studies were included in the systematic-review portion, 5 of which were included in the meta-analysis. Due to assessing multiple types of dual-tasks, 10 effects were assessed for meta-analysis across postural control studies. A random-effects model for the control group in the mediolateral direction indicated a significant overall Fisher's Z mean effect size (Δ = 0.732, p = 0.029) with high heterogeneity between studies (Q =76.61; I 2 = 88.25% P < 0.001). There were no significant differences between dual-tasking in the CAI group individually or when comparing control to CAI groups. The results of our study indicate that cognitive loading did not affect the postural control except for the control group in the mediolateral direction. Variations in dual-task results may be due to the difficulty of the task as well as the heterogeneity of CAI groups. • No differences in dual-task effects between those with CAI and controls. • The most common cognitive load during dual-tasks in CAI research is a number-based task. • Walking nor static balance may not be challenging enough to elicit a dual-task response. [ABSTRACT FROM AUTHOR]

Cognitive interventions are among the effective training-on-gait parameters; however, the effects of such trainings on inter-joints coordination has not been much considered. Can dual task and executive function training affect inter-joint coordination during walking in elderly with poor balance? Thirty elderly men were purposefully divided into three groups: 1) dual-task training group (DTG), 2) executive function training group (EFG) and 3) control group. After the pre-test, the experimental groups participated in 24 training sessions while the control group were required to do their normal daily tasks. VICON three-dimensional motion analysis system with four T20 series cameras was used to evaluate inter-joints coordination during the experiment. Participants had to walk a 12-meter path while kinematics of their joints was recorded. The inter-joint coordination at the sagittal plane and in four phases were assessed using the vector coding technique. The findings of this study showed that the greatest effect of the intervention on the coordination between the joints was in the loading and mid-stance phases (p < 0.05). Also, the variability in the coupling angle showed a significant decrease in most phases (p < 0.05). Based on the obtained results, it can be argued that the loading and mid-stance are more involved in postural control and balance because the center of gravity is transferred between the legs and the person is normally on single-leg stance in these phases. • Cognitive training increased velocity and cadence in dual task walking. • Dual task and executive function training can affect the mean coupling angles. • Inter-joint coordination was changed in the loading and mid-stance. • The variability was decreased in training groups than that in control. [ABSTRACT FROM AUTHOR]

Among different models proposed to investigate foot-ground interaction during walking [1], the foot rockers (rolling over heel, ankle, and forefoot respectively), introduced by Perry, still are one of the most straightforward approaches [2]. However, they are not modeled and studied in detail thoroughly. How does to model foot-ground interaction during walking using functional algorithms and the heel and forefoot rockers? Prospective foot data of 17 typically developed adults [34 feet, 9 m/8 f, 30.2 ± 6.9 (years), 72.4 ± 13.6 (kg), 173.5 ± 9.5 (cm)]) according to the HFMM [3] was collected for this study. The heel was modeled as a sphere, and distal metatarsals were modeled as a cylinder, interacting with the ground as ball and hinge joints, respectively (Fig.1A1). The inner part of the cylinder and sphere is assumed to be rigid, and the outer part is soft tissue, while the ground is the stationary segment (Fig1.B1-C1). The center of rotation between the heel-ground and the axis of rotation between the distal metatarsals-ground were determined using Schwartz's algorithm (Visual3d, C-Motion) [4], respectively. Thus, functional heel center (FHC) location and functional metatarsal baseline (FMTB) angles are calculated in the static position accordingly. The functional calibration motions are defined and performed by each participant. For each foot, they repeatedly circled the foot around the heel while the heel was in contact with the ground (determining FHC) and lift up and down the foot on toes repeatedly while standing on the contralateral leg (determining FMTB). The midpoint between medial and lateral calcaneus markers and line crossing the fifth distal metatarsal markers (AMTB) considered the anatomical references regarding the heel and forefoot rockers, respectively. The FHC location and FMTB angles are illustrated in Fig. 1.A2-B2-C2. The FHC is located almost between the Mid-Calc (midpoint of the medial and lateral calcaneus markers) and the Heel marker inside the foot. The average vertical deformation of the heel pad is -5.3±1.8 (mm). The FMTB and AMTB are almost parallel in the frontal plane but differ by 10° in the transverse plane. The average maximal anterior-posterior distance between FHC and FMTB is 15(mm). [Display omitted] The algorithm robustly determined FHCs and FMTBs for all participants. Modeling rockers using sphere and cylinder provides a smooth and continuous transition of motion during walking. Also, in this approach, the effect of soft tissue (namely heel pad) and the translational motion was included in the determination of the FHC and FMTB. Results could help develop foot models by offering a better interpretation of the soft tissue effect during foot contact with the ground and finding a more meaningful coordinate center and axis according to the function of the foot. The study is funded by the BMBF grant 01EC1907A [ABSTRACT FROM AUTHOR]

Customized foot orthoses (CFOs) are often recommended for the management of plantar heel pain. However, there is a lack of information regarding lower limb and multi-segment foot motion during gait. This study aimed to determine the effects of heat moulded CFOs on foot and lower limb kinematics when compared with prefabricated foot orthoses (PFOs) and wearing no orthoses (shod condition), and to determine the short-term effects of CFOs on pain intensity and foot function. The immediate effects of CFOs on the lower limb and multi-segment foot motion were assessed. Participants were then asked to use the CFOs for one month and foot pain, function, and temporal-spatial parameters were assessed at baseline and at one month follow up. Thirty-five participants (22 females), aged 40.1 (10.5) years, with a mean duration of symptoms of 12.59 months were recruited. The symptomatic limbs showed a higher forefoot varus angle and greater rearfoot and forefoot corrections were required compared to the non-symptomatic limbs. When compared with PFOs and shod conditions, CFOs provided the least forefoot and knee motion in the transverse plane during contact phase (P < 0.05, d=0.844–1.720), least rearfoot motion in the coronal plane during midstance (P < 0.05, d=0.652), and least forefoot motion in the frontal plane, knee motion in the transverse plane, and hallux motion during the propulsive phase (P < 0.05, d=0.921–1.513). Significant improvements were seen for foot pain and function (P < 0.05, d=1.390–2.231) with significant increases in cadence and walking velocity after one month of CFO use (P < 0.05, d=0.315–0.353), and those most likely to respond had greater pain and less ankle eversion (P < 0.05, d=0.855–1.115). CFOs appear to improve pathological biomechanics associated with plantar heel pain. After one month follow up, the CFOs decreased pain intensity and increased foot function, and showed significant improvements in temporal and spatial parameters of gait. • Foot orthoses could reduce pathological biomechanics related to plantar heel pain. • After follow up, foot orthoses provide positively subjective and objective outcomes. • This study offers new insights into the action of customized foot orthoses. • Present results support the foot orthosis as an intervention of plantar heel pain. [ABSTRACT FROM AUTHOR]

Forward body lean and greater horizontal ground reaction force have been associated with being able to accelerate during running. However, kinematic features which may predict acceleration during the run-to-sprint transition have not been determined. The purpose of this study was to determine which kinematic changes occur in recreationally active adults and which kinematic features may predict greater acceleration during the run-to-sprint transition. Forty-seven healthy adults completed straight line running along a 30 m track by running in at ∼4 m.s-1. A minimum of 20 trials were completed, with 25 % triggering a light to signal the participant to accelerate as fast as possible. Step characteristics (velocity, length, duration, cadence) and kinematics (neck, trunk, hip, knee and ankle angles and excursions) were determined using a radar gun and inertial measurement units, respectively. ANOVA was used to determine the step-to-step differences and a multiple linear regression was used to determine the relationship between kinematics and acceleration. There was an initial increase in trunk flexion angle during early acceleration (p < 0.001) with knee joint excursion significantly lower (p < 0.001) during loading and propulsion compared to the run-in steps. Greater acceleration was predicted using a stepwise linear regression by five variables including less neck flexion excursion and trunk flexion angle during swing of the 1st step, greater trunk flexion angle and extension excursion of the neck during propulsion of the 2nd step and greater hip flexion angle at foot strike of the 3rd step (r2 = 0.804, p < 0.001). Faster acceleration was observed when participants transitioned from an upright posture to greater forward trunk lean in the early phase of acceleration. Training the run-to-sprint transition, which was shown to have the greatest increase in velocity over the first 5 m, may be encouraged as a sports specific exercise. • Two phases of acceleration were observed during the run-to-sprint transition. • Greater trunk flexion was the most significant postural change during acceleration. • Postural changes begin at midswing of the 1st step after the signal to accelerate. • Transition from upright to greater forward trunk lean predicts faster acceleration. [ABSTRACT FROM AUTHOR]

Femoroacetabular impingement (FAI) syndrome is considered a motion-related condition. Little is known about the influence of symptom severity and cam morphology on hip biomechanics for individuals with FAI syndrome. Are hip biomechanics during running associated with symptom severity or cam morphology size in male football players with FAI syndrome? Forty-nine male, sub-elite football (soccer or Australian football) players (mean age= 26 years) with FAI syndrome completed the International Hip Outcome Tool-33 (iHOT-33) and Copenhagen Hip and Groin Outcome Score (HAGOS) and underwent radiographic evaluation. Biomechanical data were collected during overground running (3–3.5 m∙s−1) using three-dimensional motion capture technology and an embedded force plate. Various discrete hip angles and impulses of joint moments were analysed during the stance phase. Linear regression models investigated associations between running biomechanics data (dependent variables) and iHOT-33 and HAGOS scores and cam morphology size (independent variables). Hip joint angles during running were not associated with symptom severity in football players with FAI syndrome. A positive association was found between the impulse of the hip external rotation moment and HAGOS-Sport scores, such that a smaller impulse magnitude occurred with a lower HAGOS-Sport score (0.026 *10−2 [95%CI <0.001 *10−2 to 0.051 *10−2], P = 0.048). Larger cam morphology was associated with a greater peak hip adduction angle at midstance (0.073 [95%CI 0.002–0.145], P = 0.045). Hip biomechanics during running did not display strong associations with symptom severity or cam morphology size in male football players with FAI syndrome who were still participating in training and match play. Future studies might consider investigating associations during tasks that utilise end range hip joint motion or require greater muscle forces. • Bony morphology and symptom severity might impact biomechanics in FAI syndrome. • Running biomechanics, symptom severity, and hip radiographs were assessed. • Hip joint angles during running were not associated with symptom severity. • Larger cam morphology was weakly associated with a larger peak hip adduction angle. [ABSTRACT FROM AUTHOR]

Chronic Non-Specific Low Back Pain (cNSLBP) has been identified as one of the leading global causes of disability and is characterized by symptoms without clear patho-anatomical origin. The majority of clinical trials assess cNSLBP using scales or questionnaires, reporting an influence of cognitive, emotional and behavioral factors. However, few studies have explored the effect of chronic pain in daily life tasks such as walking and avoiding obstacles, which involves perceptual-motor processes to interact with the environment. Are action strategies in a horizontal aperture crossing paradigm affected by cNSLBP and which factors influence these decisions ? 15 asymptomatic adults (AA) and 15 cNSLBP participants walked along a 14 m long path, crossing through apertures ranging from 0.9 to 1.8 times their shoulder width. Their movement was measured using the Qualisys system, and pain perception was evaluated by self-administered questionnaires. The cNSLBP participants stopped rotating their shoulders for a smaller aperture relative to their shoulder width (1.18) than the AA participants (1.33). In addition, these participants walked slower, which gave them more time to make the movement adaptations necessary to cross the aperture. No correlation was found between the variables related to pain perception and the critical point but the levels of pain were low with a small variability. This study shows that during a horizontal aperture crossing task requiring shoulder rotation to pass through small apertures, cNSLBP participants appear to exhibit a riskier adaptive strategy than AA participants by minimizing rotations that could induce pain. This task thus makes it possible to discriminate between cNSLBP participants and pain-free participants without measuring the level of pain. The identification number registered in the clinical trials is NCT05337995. • Investigation of cNSLBP movement strategies in an ecological context. • Horizontal aperture crossing paradigm discriminated the influence of cNSLBP. • cNSLBP participants stopped turning their shoulder at a smaller opening. • Pain perception scores were not correlated with the critical point but were low. [ABSTRACT FROM AUTHOR]

Flexible flatfoot has demonstrated biomechanical linkages between distal and proximal lower extremities. However, supporting evidence is required to investigate the benefits of short foot exercise (SF) and short foot exercise in combination with lower extremity training (SFLE) on dynamic foot function. This study aimed to determine the effects of a 6-week SF, 6-week SFLE, or control condition (no intervention) on dynamic foot function during gait in individuals with flexible flatfoot. Forty-five individuals with flexible flatfoot were randomly assigned into three conditions: (1) SF, (2) SFLE, and (3) control conditions. Participants in two intervention programs performed daily training via telerehabilitation and a home-based exercise program. Foot kinematics and center of pressure excursion index (CPEI) during the gait, intrinsic foot muscle test, and navicular drop test were assessed at baseline and after the 6-week intervention program. Post-intervention participants in the SF and SFLE conditions showed a shorter time to the lowest medial longitudinal arch (MLA) and improved MLA motion during the stance phase compared with the baseline. In addition, participants in the SFLE conditions showed greater changes in CPEI than in the SF and control conditions. Improvements in intrinsic foot muscle and navicular drop tests were also observed in participants in both intervention programs post-intervention. A major finding of the study was the improvement in dynamic foot function during gait in individuals with flexible flatfoot after the six weeks of the SF and SFLE intervention programs. Both intervention programs appear to have the potential for inclusion in a corrective program for individuals with flexible flatfoot. • Short foot exercises can be done online. • Short foot exercises improved medial longitudinal arch and dynamic gait. • Short foot with lower extremity exercise changed the center of pressure index. [ABSTRACT FROM AUTHOR]

Chronic ankle instability (CAI) has been associated with frontal and sagittal plane kinematic differences compared to patients with no history of ankle sprain during landing tasks. Single plane kinematics are often statistically compared to identify group differences, however, the complex, multi-planar motions of the ankle allow for unique kinematic adaptations at the joint and univariate waveform analysis may be limited in the assessment of joint motion. Bivariate confidence interval analysis allows for statistical comparisons to be made when considering the simultaneous frontal and sagittal plane kinematics of the ankle. Can the bivariate confidence interval analysis identify unique joint coupling differences during a drop-vertical jump in patients with CAI? Subjects with CAI and matched healthy controls performed 15 drop-vertical jump maneuvers while kinematics were collected using an electromagnetic motion capture system. An imbedded forceplate was used to determine ground contact timing. Kinematics were analyzed using a bivariate confidence interval from 100 ms pre-ground contact to 200 ms post-ground contact. Any region where group confidence intervals did not overlap was considered statistically different. Prior to initial contact participants with CAI had greater plantar flexion from 6 ms to 21 ms and 36–63 ms prior to landing. After making ground contact differences were found from 92 ms to 101 ms and 113–122 ms. Greater plantar-flexion and eversion was identified in the patients with CAI prior to ground contact and following landing patients with CAI had greater inversion and plantarflexion compared to healthy controls. The bivariate analysis identified unique group differences compared to univariate analysis including group differences prior to landing. These unique findings indicate that comparing groups using a bivariate analysis may provide important information on the kinematic differences of patients with CAI and how multiple planes of motion compensate during dynamic landing tasks. • CI2 is a statistical technique that compares 2-dimensional waveforms. • Patients with CAI differed compared to controls during a drop vertical jump. • Bivariate comparison differed from previously reported univariate comparisons. • The bivariate waveform comparison should be considered in the kinematic analysis. [ABSTRACT FROM AUTHOR]

The development of plantar pressure insoles has made them a potential replacement for force plates. These wearable devices can measure multiple steps and might be used outside of the lab environment for rehabilitation and evaluation of sport performance. However, they can only measure the vertical force which does not completely represent the vertical ground reaction force. In addition, they are not able to measure shear forces which play an import role in the dynamic performance of individuals. Indirect approaches might be implemented to improve the accuracy of the force estimated by plantar pressure systems. The aim of this study was to predict the vertical and shear components of ground reaction force from plantar pressure data using recurrent neural networks. Ground reaction force and plantar pressure data were collected from 16 healthy individuals during 10 trials of walking and five trials of jogging using Bertec force plates at 1000 Hz and FScan plantar pressure insoles at 100 Hz. A long short-term memory neural network was built to consider the time dependency of pressure and force data in predictions. The data were split into three subsets of train, to train the model, evaluate, to optimize the model hyperparameters, and test sets, to assess the accuracy of the model predictions. The results of this study showed that our long short-term memory model could accurately predict the shear and vertical force components during walking and jogging. The predictions were more accurate during walking compared to jogging. In addition, the predictions of mediolateral force had higher error and lower correlation compared to vertical and anteroposterior components. The long short-term memory model developed in this study may be an acceptable option for accurate estimation of ground reaction force during outdoor activities which can have significant impacts in rehabilitation, sport performance, and gaming. • Potential use of neural networks to enhance the real-time force of pressure insoles. • LSTM neural networks can accurately predict vertical & shear ground reaction force. • The GRF predicted from pressure data would have clinical and sport applications. [ABSTRACT FROM AUTHOR]

This meta-analysis was performed to compare the spatiotemporal, kinematic, and kinetic gait characteristics during level walking between total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA). An electronic database literature search was performed to screen clinical trials which were included the studies evaluating not only spatiotemporal, kinematic, and kinetic gait parameters, but also knee range of motion and knee score (Knee Society Score and Oxford Knee Score, i.e., KSS and OKS). The data analysis was performed using statistical software Stata 14.0 and Review Manager 5.4. Thirteen studies (369 knees) that met the criteria were eventually included in this meta-analysis. The results revealed significant differences between UKA and TKA with regard to walking speed (P = 0.04), stride length (P = 0.02), maximum knee flexion at loading (P = 0.001), the 1st peak of vert-GRF (P = 0.006), the 1st valley of vert-GRF (P = 0.007), knee internal rotational moment (P = 0.04), knee extension (P < 0.00001), and KSS Function score (P = 0.05). In contrast, there were no statistical differences in the remaining spatiotemporal, kinematic, and kinetic gait parameters. Medial UKA design is superior to TKA design with regard to walking speed, stride length, maximum knee flexion at loading, the 1st peak and the 1st valley of vert-GRF, knee internal rotational moment, knee extension, and KSS Function score. And it could provide a stronger basis for physicians to make clinical decisions. • For spatiotemporal aspect, UKA is superior to TKA in walking speed and stride length. • For kinematics, UKA is superior to TKA in maximum knee flexion at loading. • For vert-GRF in kinetics, UKA is superior to TKA in the 1st peak and the 1st valley. • For knee moment in kinetics, UKA is superior to TKA in internal rotational moment. • For ROM and score, UKA is superior to TKA in knee extension and KSS Function score. [ABSTRACT FROM AUTHOR]

Markerless motion capture systems have the potential to make clinical gait analysis more efficient and convenient. Theia3D is a commercially available markerless system that may serve as an alternative to traditional gait analysis for clinical gait laboratories. What is the concurrent validity of markerless gait analysis using Theia3D compared to traditional marker-based gait analysis in pediatric clinical gait patients? Thirty-six patients (20 male, age 2–25 years) with a range of diagnoses underwent clinical gait analysis with data being captured concurrently by a traditional marker-based motion capture system (Vicon Nexus) and a commercial markerless system (Theia3D). Multiple left strides were averaged for each subject, and the difference in kinematics (Theia - Vicon) was calculated over the gait cycle and evaluated using root mean square difference (RMSD), mean difference, and RMSD after subtracting the mean value across the gait cycle (RMSD offset). Sub-analysis was performed for 25 patients with foot deformities, 9 wearing ankle-foot orthoses, and 6 walking with assistance (cane, crutches, walker, or handheld). Kinematics showed similar patterns between the marker-based and markerless systems. RMSD was < 6° except for pelvic tilt, hip flexion, ankle inversion, foot progression, and transverse plane rotation of the hip, knee, and ankle. These measures mainly differed due to an offset between the curves. After adjusting for offsets, all RMSD offset were < 6°. RMSD was larger for patients with foot deformities, wearing orthoses, or using assistive devices, but all RMSD offset were still < 8°. In some cases, however, the markerless system had greater trial-to-trial variability, showed a larger knee varus "bump" in swing, or failed to track the subject. This study provides preliminary evidence of concurrent validity of Theia3D for pediatric patients with abnormal gait. However, some questions remain regarding identification of the knee axis and for patients with foot deformity or assistive devices. • Theia3D and Plug-in-Gait produce similar kinematic patterns. • Markerless kinematic curves are offset from marker-based for some variables. • Systems differ more with foot deformity, orthotics, and assistive devices. • Questions remain about Theia3D knee axis definition and hip rotation. [ABSTRACT FROM AUTHOR]

Gait analysis relies on the accurate and precise identification of anatomical landmarks to provide reliable and reproducible data. More specifically, the precision of marker placement among repeated measurements is responsible for increased variability in the output gait data. The objective of this study was to quantify the precision of marker placement on the lower limbs by a test-retest procedure and to investigate its propagation to kinematic data. The protocol was tested on a cohort of eight asymptomatic adults involving four evaluators, with different levels of experience. Each evaluator performed, three repeated marker placements for each participant. The standard deviation was used to calculate the precision of the marker placement, the precision of the orientation of the anatomical (segment) coordinate systems, and the precision of the lower limb kinematics. In addition, one-way ANOVA was used to compare the intra-evaluator marker placement precision and kinematic precisions among the different levels of the evaluator's experience. Finally, a Pearson correlation between marker placement precision and kinematic precision was analyzed. Results have shown a precision of skin markers within 10 mm and 12 mm for intra-evaluator and inter-evaluator, respectively. Analysis of kinematic data showed good to moderate reliability for all parameters apart from hip and knee rotation that demonstrated poor intra- and inter-evaluator precision. Inter-trial variability was observed reduced than intra- and inter-evaluator variability. Moreover, experience had a positive impact on kinematic reliability since evaluators with higher experience showed a statistically significant increase in precision for most kinematic parameters. However, no correlation was observed between marker placement precision and kinematic precision which indicates that an error in the placement of one specific marker can be compensated or enhanced, in a non-linear way, by an error in the placement of other markers. • Evaluator's experience plays positive role on some kinematic parameters of gait. • No correlation between marker placement precision and kinematic variability. • Wands and femoral epicondyle markers are the lowest precise in marker placement. [ABSTRACT FROM AUTHOR]

Previous studies have investigated the effect of either different load or different surface conditions, such as overground or treadmill walking, on human biomechanics. However, studies combining these two aspects are scarce. The purpose of this study was to quantify the difference in spatiotemporal parameters, lower extremity joint kinematics, vertical ground reaction forces (vGRF) and muscle activity between normal bodyweight (100 %BW) and 20 % increased bodyweight (120 %BW) during overground and treadmill walking. Ten healthy young adults walked overground at self-selected speed and on an instrumented treadmill set to the overground speed. Spatiotemporal parameters, 3-dimensional lower extremity kinematics, vGRF and muscle activity were measured and compared between conditions. The stance phase was longer for 120 %BW than 100 %BW in both overground and treadmill walking. Further, the stance phase was longer and cadence higher in treadmill than overground walking for both load conditions. Knee flexion angles were more than 3° greater in the second half of swing in treadmill than in overground walking. The vGRF was higher for 120 %BW compared to 100 %BW on both surfaces (treadmill, first peak: +18.6 %BW; second peak: +13.5 %BW; overground, first peak: +22.2 %BW; second peak: +19.8 %BW). Differences between conditions greater than 20 % were observed in short periods during the gait cycle for vastus medialis, vastus lateralis and semitendinosus. Results regarding the effects of carrying additional load using a weight vest on joint kinematics during treadmill walking may be translated to overground walking but some changes in muscle activation can be expected. • Combined effects of additional load and walking surface were investigated. • Effects of additional load on ground reaction forces were systematic. • Effects of additional load on joint kinematics were likely not clinically relevant. • Differences in muscle activity occurred mainly before and after heel-strike. [ABSTRACT FROM AUTHOR]

Patients after total hip arthroplasty (THA) have altered hip kinematics compared to healthy controls, specifically hip extension and range of motion are lower. Exploring pelvis-thigh coordination patterns and coordination variability may help to elucidate why differences in hip kinematics are evident in patients following THA. Do sagittal plane hip, pelvis and thigh kinematics, and pelvis-thigh movement coordination and coordination variability differ between patients following THA and healthy controls during walking? Sagittal plane hip, pelvis and thigh kinematics were collected using a three-dimensional motion capture system while 10 patients who had undergone THA and 10 controls walked at a self-selected pace. A modified vector coding technique was used to quantify pelvis-thigh coordination and coordination variability patterns. Peak hip, pelvis and thigh kinematics and ranges of motion, and movement coordination and coordination variability patterns were quantified and compared between groups. Patients after THA have significantly (p ≤.036; g ≥ 0.995) smaller peak hip extension and range of motion, and peak thigh anterior tilt and range of motion compared to controls. Additionally, patients following THA have significantly (p ≤.037; g ≥ 0.646) more in-phase distally and less anti-phase distally dominated pelvis-thigh movement coordination patterns compared to controls. The smaller peak hip extension and range of motion displayed by patients following THA is due to smaller peak anterior tilt of the thigh, which in turn limits thigh range of motion. The lower sagittal plane thigh, and in turn hip, motion used by patients after THA may be due to increases in the in-phase coordination of pelvis-thigh motion patterns, which cause the pelvis and thigh to work as a singular functional unit. • Patients after THA report less hip extension and sagittal plane range of motion. • Altered hip kinematics are likely due to reduced thigh motion. • Patients after THA use more in-phase pelvis-thigh coordination compared to controls. • Patients after THA use less anti-phase pelvis-thigh coordination compared to controls. [ABSTRACT FROM AUTHOR]

Walking is the most important mode of human locomotion; however, the ability to walk often decreases with age. Age-related differences in lower-limb kinematics during gait may differ depending on sex. However, the question of the compounded effects of age and sex on gait kinematics remains unsolved. The present study aimed to clarify the interaction between age and sex in differences in gait kinematics of community-dwelling middle-age and older individuals. This study included 836 community-dwelling middle-age and older adults (61.8 % female). Joint motion during comfortable gait was measured using magnetic and inertial measurement units. Hip, knee, and ankle joint angles were calculated in the sagittal plane. Participants were divided into four groups according to age: 50–59, 60–69, 70–79, and 80–89 years. The interaction of sex and age on spatiotemporal gait parameters and the peak value of joint angles was analyzed using two-way analysis of variance (ANOVA) and Tukey's post hoc test. Gait speed (F = 43.92, P < 0.001), step length (F = 73.00, P < 0.001), hip extension (F = 12.89, P = 0.002), knee flexion (F = 39.99, P < 0.001), and ankle plantar flexion (F = 27.43, P < 0.001) significantly decreased with age. Significant differences according to sex were observed in all parameters except gait speed. Significant age and sex interaction effects were observed for knee flexion (F = 4.97, P = 0.002) and ankle dorsiflexion (F = 4.04, P = 0.007). A significant interaction effect of age and sex was observed for peak angle of knee flexion and ankle dorsiflexion during gait. In particular, the knee flexion angle among females during gait began to decrease from 60 years of age, and the decreasing trend was faster and more prominent than that among males. • Gait speed, step length and joint angle decreased with age, particularly among those >60 years old. • Significant age and sex interaction effects were observed in knee flexion and ankle dorsiflexion. • Females exhibited decreased knee flexion and increased ankle dorsiflexion with increases in age. [ABSTRACT FROM AUTHOR]

Charcot-Marie-Tooth disease (CMT) can cause progressive muscle weakness and contracture, leading to gait abnormalities such as increased and delayed peak ankle dorsiflexion and reduced ankle power generation in terminal stance. Understanding strength loss on ankle function during gait is important for interpreting treatment outcomes and evaluating new therapies designed to improve gait. Do ankle kinematics and kinetics vary as a function of age, disease progression with associated loss of muscle strength and CMT type in youth with CMT types 1 and 2? A prospective convenience sample of 45 participants with CMT1 and 2, ages 7–22 years, underwent comprehensive gait analysis. Seventeen patients underwent repeat analyses totaling 67 tests. Generalized mixed effects linear modeling was used to compare CMT1 versus CMT2 and to examine the effects of age on ankle strength, range of motion, kinematics, and kinetics within each CMT type. Plantarflexor and dorsiflexor strength were less in CMT2 compared with CMT1 (p ≤ 0.05), while peak dorsiflexion in terminal stance (TST) was greater (p = 0.02). Peak plantarflexion moment and power generation were also less in CMT2 (p ≤ 0.02). In CMT1, peak dorsiflexion in TST increased with age through 13 years (p = 0.004); then plateaued in the normal range (p = 0.73). Peak ankle angle in mid-swing was closely related to the angle in TST (p < 0.001) following a similar pattern with age. In CMT2, no significant associations were observed between age, peak dorsiflexion in TST, and peak ankle angle in mid-swing (p ≥ 0.19). There were no consistent trends with age for individual patients with repeat tests. The heterogeneity of joint level impairments and gait kinematics and kinetics point to the importance of having an in-depth understanding of gait at the individual patient level using comprehensive gait analysis including valid and reliable strength measures. • In CMT1 peak dorsiflexion in terminal stance (TST) increased through age 13. • In CMT1 peak dorsiflexion in TST plateaued in the normal range after 13. • In CMT1 peak ankle angle in mid-swing was closely related to the angle in TST. • In CMT2 there was no significant association of ankle function with age. • Heterogeneity in gait highlights the need to understand patient-specific gait changes. [ABSTRACT FROM AUTHOR]

Comparing the performance of one leg to another is a common means of assessing running gait to help inform clinical management strategies. Various methods are employed to quantify asymmetries between limbs. However, limited data is available describing the amount of asymmetry that may be expected during running and no index has been identified as preferable for making a clinical determination of asymmetry. Therefore, this study aimed to describe amounts of asymmetry in collegiate cross-country runners and compare different methods of calculating asymmetry. What can be expected as a normal amount of asymmetry in biomechanical variables in healthy runners when using different indices to quantify limb symmetry? Sixty-three (29 male and 34 female) runners participated. Running mechanics were assessed during overground running using 3D motion capture and a musculoskeletal model using static optimization to estimate muscle forces. Independent t-tests were utilized to determine statistical differences in variables between legs. Different methods of quantifying asymmetry were then compared to statistical differences between limbs to determine cut-off values and the sensitivity and specificity of each method. A large portion of runners demonstrated asymmetry during running. Kinematic variables can be expected to have small differences (2–3 degrees) between limbs while muscle forces may show greater amounts of asymmetry. The sensitivities and specificities for each method of calculating asymmetry were similar, however, different methods led to different cut-off values for each variable investigated. Asymmetry can be expected between limbs during running. However, when assessing asymmetry, practitioners should consider the joint, variable, and method of calculating asymmetry when determining differences between limbs. • Kinematic asymmetries are typically within 2–3 degrees. • Many runners show large asymmetries in muscle forces. • Methods used in calculating asymmetry show similar accuracy. • Cut-off values depend on method, joint, and variable being assessed. • Caution is advised when using arbitrary cut-off values to determine asymmetry. [ABSTRACT FROM AUTHOR]

Dual Task (DT) walking in everyday life is the norm rather than the exception. Complex cognitive-motor strategies are employed during DT and it is necessary to coordinate and regulate neural resources to ensure adequate performance. However, the underlying neurophysiology involved is not fully understood. Therefore, the aim of this study was to examine the neurophysiology and gait kinematics during DT gait. Our main research question was whether gait kinematics changed during DT walking for healthy young adults and whether this is reflected in brain activity. Ten healthy young adults walked on a treadmill, performed a Flanker test while standing and performed the Flanker test while walking on a treadmill. Electroencephalography (EEG), spatial temporal, and kinematic data was recorded and analyzed. Average alpha and beta activities were modulated during DT walking compared to single task (ST) walking while ERPs during the Flanker test showed larger P300 amplitudes and longer latencies for DT compared to standing. Cadence reduced and cadence variability increased during DT compared to ST whilst kinematic results showed that hip and knee flexions decreased, and the center of mass moved slightly back in the sagittal plane. It was found that healthy young adults employed a cognitive-motor strategy that included directing more neural resources to the cognitive task while adopting a more upright posture during DT walking. • Recorded EEG, kinematics and gait parameters during dual task walking. • We found modulated alpha and beta activity in frontal and central regions. • Increased P300 amplitude and latencies at frontal and central electrodes. • Decreased hip and knee flexion with altered pelvic COM during dual tasking. • Kinematic changes during dual tasking to ensure more upright posture. [ABSTRACT FROM AUTHOR]

The determination of the knee joint axis (KJA) via specific calibration movements has become a promising alternative to the conventional approach to determine this axis based on regression equations or directly via marker placement on bony landmarks of the knee. Since the orientation of the KJA may differ between methods, it has direct influence on hip rotation and may therefore influence clinical decision making in context of transverse plane gait deviations. Research question: Does a functional KJA calibration lead to clinically relevant differences in hip rotation estimates during gait compared to the conventional method? 95 subjects (age: 19.9 years; BMI: 21.1 kg/m2), including 71 patients with potential rotation malalignment, were prospectively examined and underwent 3D gait analysis. For the conventional approach the KJA was determined by applying a knee alignment device, for the functional approach subjects were asked to perform two different calibration movements. Each procedure was performed twice. Mean hip rotation in stance (mHipRotSt) was determined following the conventional and the functional KJA calibration. Deming regression analysis for the comparison of conventional and functionally measured hip rotation revealed a systematic and substantial difference between methods (slope: 0.63; intercept: 0.31°). Measurement repetition with the knee alignment device revealed typical errors around 5°, whereas the functional methods lead to profoundly smaller errors around 1-2° with slightly inferior results for SQUAT compared to FLEX. However, when compared to conventional frontal plane video-taping, the conventional method seemed to reflect the more consistent results. The systematic linear discrepancy in mHipRotSt obtained by a functional approach as compared to the conventional approach appears critical since patients with severe internal or external rotation gait may be misjudged in function when receiving corrective procedures such as femoral derotation osteotomy. • Gait analysis was performed in 95 subjects with and without rotational malalignments. • A conventional and two functional approaches were applied for knee axis determination. • Hip rotation differs almost by a factor of two between approaches (linear slopes 0.63; 0.71). • The outcome with a functional approach (FLEX, SQUAT) leads to a higher precision. • The outcome with the conventional approach corresponds better with clinical evaluation. [ABSTRACT FROM AUTHOR]

Interval training (IT) is influenced by several variables and its design. However, there is no consensus about the acute effects of this type of training on running kinematics and gait patterns due to the variety of session designs. The aim of this systematic review was to determine the acute effects of IT on gait patterns and running kinematics in endurance runners depending on the characteristics of the training sessions. A systematic search on four databases (Pubmed, WOS, Medline, and Scopus) was conducted on February 22, 2022. After analyzing 655 articles, studies were included if they met the inclusion criteria developed according to the PICO model. Nine studies were finally included. Only two of these studies measured kinematics changes during IT bouts while seven measured pre-post changes of these parameters. The quality scores of the included studies in the review averaged 5.44 (good quality) points using the modified PEDro scale. The observed changes in running kinematics during IT sessions were an increase in stride frequency, contact time and vertical displacement of center of mass. Regarding the type of IT, anaerobic and short aerobic interval sessions (200–1000 m) should include long recovery periods (2–3 min) to avoid the increase of stride frequency, contact time and vertical oscillation of the center of mass as a results of muscle fatigue. For long aerobic interval sessions (>1000 m), a short recovery (1–2 min) between bouts do not induce a high level of muscle fatigue nor modifications in gait patterns. Coaches and athletes must consider the relative intensity and recovery periods of IT, and the type of IT, to prevent excessive fatigue which can negatively affect running kinematics. • Longer rest periods (∼2 min) during IT protocols help support running kinematics. • In long aerobic IT, recovery < 1 min ensures that running kinematics remains unchanged. • In anaerobic IT, a recovery time ∼4 min helps to tolerate neuromuscular fatigue. • Cardiovascular fatigue appears before neuromuscular fatigue. • Monitoring of cardiometabolic parameters is recommended to improve fatigue control. [ABSTRACT FROM AUTHOR]

Past work has identified relationships between postural stability and joint kinematics during balance and sit-to-stand tasks. However, this work has not been extended to a thorough examination of these relationships during gait, and how these relationships change with age. An improved understanding of age-related changes in these relationships during gait is necessary to identify early predictors of gait impairments and implement targeted interventions to prevent functional decline in older adulthood. How does age affect relationships between time-varying signals representing joint/segment kinematics and postural stability during gait? Three-dimensional, whole-body motion capture data from 48 participants (19 younger, 29 older) performing overground gait were used in this secondary analysis. Lower extremity joint angles, trunk segment angles, and margins of stability in the antero-posterior and mediolateral directions were subsequently derived. Pairings of angle and margin of stability signals were cross-correlated across the gait cycle. Metrics representing the strength of relationships were extracted from the cross-correlation functions and compared between groups. At the ankle, significant age-related differences were only identified in the mediolateral direction, with older adults' coefficients being of greater magnitude and more tightly clustered, relative to younger adults. Differences were observed in both directions at the hip, with an overall trend of greater-magnitude and more tightly clustered coefficients among younger adults. For the trunk, the groups exhibited coefficients of opposite signs in the antero-posterior direction. While overall gait performance was similar between groups, age-related differences were identified in relationships between postural stability and kinematics, with stronger relationships at the hip and ankle for younger and older adults, respectively. Relationships between postural stability and kinematics may have potential as a marker for the early identification of gait impairment and/or dysfunction in older adulthood, and for quantifying the effectiveness of interventions to reduce gait impairment. • Relationships between postural stability and lower limb kinematics were quantified. • Relationship strengths differed between younger and older adults. • The nature of these age-related differences was joint-dependent. • These relationships may be an indicator of age-related declines in gait function. [ABSTRACT FROM AUTHOR]

Bilateral vertical ground reaction force (VGRF) and knee extension moment asymmetries are commonly observed during jumping and landing tasks following anterior cruciate ligament (ACL) reconstructions (ACLR) in collegiate athletes. Kinetic asymmetries during landings are associated with increased ACL re-injury risk. Efforts have been made to predict bilateral kinetic asymmetries using trunk kinematics during squats but not during jump-landings. To determine the correlations between trunk kinematics (medial-lateral shoulder positions, medial-lateral hip positions, and lateral trunk bending angles) and bilateral kinetic asymmetries (VGRF and knee extension moments) during double-leg jump-landings in collegiate athletes following ACLR. Fifteen National Collegiate Athletic Association Division I athletes who had ACLR in the past 24 months participated. Eleven of them performed two assessments over the study period for a total of 26 assessments for data analyses. Athletes performed three double-leg countermovement jumps. Kinematics and kinetics data were collected. Medial-lateral shoulder and hip positions relative to ankle positions, lateral trunk bending angles, and kinetic asymmetries were calculated during the jumping (the lowest hip position until takeoff) and landing (the first 100 ms after initial contact) phases. Medial-lateral shoulder positions correlated with VGRF (r = 0.63, p < 0.001) and knee moment asymmetries (r = 0.53, p = 0.006) in the jumping phase. Medial-lateral hip positions correlated with VGRF (r = 0.61, p < 0.001; r = 0.52, p = 0.006) and knee moment asymmetries (r = 0.55, p = 0.004; r = 0.61, p < 0.001) in both jumping and landing phases. Medial-lateral hip positions correlated with kinetic asymmetries during double-leg jump-landings in collegiate athletes following ACLR. A 2D assessment using a standard video camera might be used as a low-cost and clinically applicable tool to assess bilateral kinetic asymmetries by quantifying medial-lateral hip positions during jump-landings following ACLR. • Collegiate athletes following ACLR showed kinetic asymmetries in jump-landings. • Medial-lateral hip positions correlated with kinetic asymmetries in jump-landings. • A hip position above the center of bilateral ankles may be a target of assessment. [ABSTRACT FROM AUTHOR]

The Gait Profile Score (GPS) requires a comparative dataset, to identify altered mechanics in persons with a gait abnormality. This gait index has been shown to be useful for identifying gait pathology prior to the assessment of treatment outcomes. Though studies have shown differences in kinematic normative datasets between different testing sites, there is limited information available on the changes in GPS score based on normative dataset selection. The aim of this study was to quantify the influence of normative reference data from two institutions, on the GPS and Gait Variable Scores (GVS), calculated on the same group of patients with Cerebral Palsy. Seventy patients (Avg. age: 12.1 ± 2.9) diagnosed with CP underwent gait analysis during walking at a self-selected speed at Scottish Rite for Children (SRC). GPS and GVS scores were determined using normative kinematic data at a self-selected speed from, 83 typically developing children ages 4–17 from Gillette, and the same age range of children from SRC's normative dataset. Average normalized speed was compared between institutions. Signed rank tests were performed on the GPS and GVS scores using each institution's dataset. Spearman's correlations between scores using SRC and Gillette were determined within GMFCS level. Normalized speed was comparable between each institution's datasets. Within each GMFCS level, significant differences when using SRC vs. Gillette were found in most scores (p < 0.05). Scores were moderately to strongly correlated within each GMFCS level (range ρ = 0.448–0.998). Significant statistical differences were found in GPS and GVS scores but were within the range of previously reported variation across multiple sites. Caution and consideration may need to be taken when reporting GPS and GVS scores that are calculated utilizing different normative datasets as these scores may not be equivalent. • Gait Profile scores are influenced by normative dataset selection. • Children with Cerebral Palsy will have different Gait Profile Scores. • Consistency across studies should be a consideration when reporting outcomes. [ABSTRACT FROM AUTHOR]

The walking knee kinematic results of generalized joint hypermobility (GJH) subjects were controversial in previous studies. We proposed that this could be related to the knee statuses of GJH subjects with/without knee hyperextension (KH) and assumed that there are significant sagittal knee kinematic differences between GJH subjects with/without KH during gait. Do GJH subjects with KH exhibit significantly different kinematic characteristics than those without KH during walking? 35 GJH subjects without KH, 34 GJH subjects with KH, and 30 healthy controls were recruited in this study. A three–dimensional gait analysis system was used to record and compare the knee kinematics of the participants. Significant walking knee kinematics differences were found between GJH subjects with/without KH during walking. GJH subjects without KH had greater flexion angles (4.7–6.0°, 24–53 % gait cycle (GC), p < 0.001; 5.1–6.1°, 65–77 % GC, p = 0.008) and anterior tibial translation (ATT) (3.3–4.1 mm, 0–4 % GC, p = 0.015; 3.8–4.3 mm, 91–100 % GC, p = 0.01) than those with KH. Compared to controls, GJH without KH exhibited increased ATT (4.0–5.7 mm, 0–26 % GC, p < 0.001; 5.1–6.7 mm, 78–100 % GC, p < 0.001), and range of motion of ATT (3.3 mm, p = 0.028) whereas GJH with KH only exhibited increased extension angle (6.9–7.3°, 62–66 % GC, p = 0.015) during walking. The findings confirmed the hypothesis and suggested that GJH subjects without KH had more walking ATT and flexion angle asymmetries than those with KH. This may raise concerns about the differences in knee health and risk of knee diseases between GJH subjects with/without KH. However, further investigations should be done to explore the exact influence of walking ATT and flexion angle asymmetries in GJH subjects without KH. • GJH subjects with/without KH have significantly different knee kinematics. • GJH subjects without KH exhibited more ATT and flexion angle than those with KH. • Kinematic asymmetries of GJH subjects without KH may raise health concerns of knee. [ABSTRACT FROM AUTHOR]