Search

The use of technology has increased over the last decade across all surgical specialties. Robotics is the ultimate tool and can accomplish accuracy and consistency for surgeons executing their preoperative plan. In orthopedic surgery, robotic-assisted knee and hip arthroplasty techniques have experienced rapid growth, and the next field of interest is, without a doubt, shoulder arthroplasty. While the survival rates extend to over 90% at 10 years of follow-up and overall satisfaction rates are very high, some report that up to 10% of the patients with a shoulder replacement remain dissatisfied with their postoperative range of motion and overall functional outcome. There have been numerous advances in implant designs and materials as well as the introduction of enhanced recovery programs, however, reported patient outcomes, and reoperation rates may not always have significantly benefited from those advances in shoulder arthroplasty over the last two decades. Lately, the digitalization of shoulder arthroplasty has drawn a lot of attention with the intent to improve the correction of joint deformities and component implantation, possibly leading to enhanced patient outcomes after shoulder arthroplasty. The potential benefits of shoulder robots are multiple. First, by converting data from imaging or intraoperative anatomy mapping, a patient-specific 3-dimensional representation of the joint may facilitate surgical planning and subsequent boundary control for the bony resections, reaming, and implant positioning. Second, the system may allow intraoperative assessment of the range of motion and joint stability. Third, research may be facilitated and encouraged by supporting case-by-case data collection. This next evolution in surgical technology aims to make shoulder replacements accurate and reproducible in both easy and challenging shoulders and usable by both low-volume and highly experienced surgeons. [ABSTRACT FROM AUTHOR]

There is growing interest in the role of social support during the recovery after hip fractures. The research to date has been mainly focused on structural support, with few studies concerned with functional support. This study examined the effects of both functional and structural aspects of social support on rehabilitation outcomes among older adults with hip fracture surgery. Prospective cohort study. Consecutive older adults (≥60 years) with hip fracture surgery who underwent inpatient rehabilitation in a post-acute care facility in Singapore between January 11, 2021, and October 30, 2021 (n = 112). We administered the Medical Outcome Study–Social Support Survey (MOS-SSS) to assess perceived functional support of patients and used living arrangement as an indicator for structural support. Participants were followed up over the inpatient stay at the post-acute care facility until discharge; thereafter, rehabilitation efficiency (REy) and rehabilitation effectiveness (REs) were evaluated. Multiple linear regressions were performed to examine the associations of MOS-SSS score and living arrangement with REy and REs, respectively, adjusting for age, gender, ethnicity, comorbidity, body mass index, prefracture function, type of fracture, and length of stay. Perceived functional support had positive associations with rehabilitation outcomes. A 1-unit increase in MOS-SSS total score was associated with 0.15 units (95% CI 0.03–0.3, P =.029) greater gain in physical function after a typical 1-month stay, and 0.21 units (95% CI 0.01–0.41, P =.040) higher achievement in potential functional improvement upon discharge. In contrast, no association was observed between structural support and rehabilitation outcomes. Perceived functional support may significantly impact the recovery of older adults with hip fracture during the inpatient rehabilitation process, independent of structural support. Our findings suggest the potential of incorporating interventions enhancing perceived functional support of patients into the post-acute care model for hip fracture. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate whether there is a relationship between gluteus medius trigger points with hip passive range of motion and hip muscle strength in people with chronic nonspecific low back pain (LBP). This was a cross-sectional, blinded study that took place in 2 rural communities in New Zealand. Assessments were carried out in physiotherapy clinics in these towns. A total of 42 participants over 18 years old experiencing chronic nonspecific LBP were recruited. After meeting inclusion criteria, participants completed the following 3 questionnaires: Numerical Pain Rating Scale, Oswestry Disability Index, and Tampa Scale of Kinesiophobia. The primary researcher (a physiotherapist) assessed each participant's bilateral hip passive range of movement (using an inclinometer) and muscle strength (using a dynamometer). Following this, a blinded trigger point assessor examined the gluteus medius muscles for the presence of active and latent trigger points. General linear modeling using univariate analysis revealed that there was a positive association between hip strength and trigger point status (P =.03 left internal rotation, P =.04 right internal rotation, and P =.02 right abduction). Participants with no trigger points showed higher strength values (eg, right internal rotation standard error: 0.64), and those with trigger points showed lower strength. Overall, muscles exhibiting latent trigger points were the weakest (eg, right internal rotation standard error: 0.67). The presence of active or latent gluteus medius trigger points was associated with hip weakness in adults with chronic nonspecific LBP. There was no association between gluteus medius trigger points and hip passive range of movement. [ABSTRACT FROM AUTHOR]

Background: In modern society, car usage is one of the most important activities of daily living. However, the three-dimensional (3D) mechanics of getting into and out of a car in total hip arthroplasty (THA) patients have not been studied.Research Question: This study aimed to elucidate the hip kinematics and kinetics of unilateral THA patients while getting into and out of a car.Methods: 3D motion and ground reaction force data were collected for 40 unilateral primary THA and 30 control participants using motion capture of getting into and out of a car. Normalized joint power was used to determine the individual joint contribution and was calculated by dividing the power of each joint by the total lower-extremity power. These kinematic and kinetic data were compared between unilateral THA and control participants.Results: When getting into the car using the surgical side as the pivot limb, the peak flexion, abduction angle, and normalized power of the pivot hip were significantly lower, and the normalized power of the contralateral ankle was significantly higher. The peak flexion and abduction angle of the pivot hip were significantly lower, and normalized contralateral hip power was significantly higher when getting out of the car. In getting into and out of the car using the contralateral side as the pivot limb, there was no significant difference in the range of motion (RoM) and normalized joint power.Significance: The restoration of RoM and muscle strength in the surgical hip joint and adopting the normal side as the pivot limb may allow for a more appropriate balance in motion of getting into and out of a car, which will lead to safe mobility, assist in social participation, and improved quality of life.Level Of Evidence: Level III, therapeutic study. [ABSTRACT FROM AUTHOR]

Slipped capital femoral epiphysis is a prevalent pediatric hip disorder. Recent studies suggest the spine's sagittal profile may influence the proximal femoral growth plate's slippage, an aspect not extensively explored. This study utilizes finite element analysis to investigate how various spinopelvic alignments affect shear stress and growth plate slip. A finite element model was developed from CT scans of a healthy adult male lumbar spine, pelvis, and femurs. The model was subjected to various sagittal alignments through reorientation. Simulations of two-leg stance, one-leg stance, walking heel strike, ascending stairs heel strike, and descending stairs heel strike were conducted. Parameters measured included hip joint contact area, stress, and maximum growth plate Tresca (shear) stress. Posterior pelvic tilt cases indicated larger shear stresses compared to the anterior pelvic tilt variants except in two leg stance. Two leg stance resulted in decreases in the posterior tilted pelvi variants hip contact and growth plate Tresca stress compared to anterior tilted pelvi, however a combination of posterior pelvic tilt and high pelvic incidence indicated larger shear stresses on the growth plate. One leg stance and heal strike resulted in higher shear stress on the growth plate in posterior pelvic tilt variants compared to anterior pelvic tilt, with a combination of posterior pelvic tilt and high pelvic incidence resulting in the largest shear. Our findings suggest that posterior pelvic tilt and high pelvic incidence may lead to increased shear stress at the growth plate. Activities performed in patients with these alignments may predispose to biomechanical loading that shears the growth plate, potentially leading to slip. • Exaggerated hip-spine alignment contributes to growth plate shear. • Variation in spinopelvic alignment alters hip joint cartilage mechanics. • Spinopelvic asymmetry may be a contributing factor to growth plate slip. [ABSTRACT FROM AUTHOR]

Background: Shoulder pain may be related to biomechanical dysfunctions in the kinetic chain.Objective: To compare the mobility and muscular endurance of thoracolumbar spine and hip, and the neuromuscular control of the lower extremity of individuals with and without shoulder pain and to determine the discriminative capacity between groups of these variables.Design: A cross-sectional study.Method: One hundred and two individuals with and without shoulder pain were evaluated to range of motion (ROM) of the thoracolumbar spine and hips, the muscular endurance time of the thoracolumbar spine and hips muscles, and the neuromuscular control of the lower extremity, by the Star Excursion Balance Test (SEBT).Results: Individuals with shoulder pain presented lower ROM and muscular endurance time in all tests evaluated (p < 0.01-p = 0.03), greater perception of pain during all ROM and muscle endurance (p < 0.01-p = 0.04) evaluations, and less neuromuscular control of the lower extremity in the compound reach (p < 0.01-p = 0.01), anterior and posteromedial (p < 0.01-p = 0.04) directions of the SEBT on both sides. The anterior reach direction of the SEBT of the contralateral limb to the shoulder pain (AUC=0.80, cut-off point=47.7%) presented excellent capacity to discriminate individuals with shoulder pain, while the other variables showed between acceptable and small capacity (AUC=0.58-0.76).Conclusion: Individuals with chronic shoulder pain presented alterations in joint mobility, muscular endurance time of the thoracolumbar spine and hips and neuromuscular control of the lower extremity. The anterior reach of the SEBT of the contralateral limb showed excellent discriminative capacity. [ABSTRACT FROM AUTHOR]

Background: The way movement-based exercises affect targeted muscles is not always obvious. Side stepping with an elastic band around the forefeet is aimed at strengthening hip abductors and lateral rotator muscles, with the premise that it creates an external torque of adduction and medial rotation of the femur around the pelvis that needs to be counteracted by hip muscles. However, hip torques during this exercise have not been previously quantified.Research Question: Is the premise that the side-stepping exercise creates an external torque of adduction and medial rotation of the femur around the pelvis correct?Methods: Thirty-six adults performed the exercise in an upright and a squat posture while 3D kinetic and kinematic data were collected. Hip muscle torques were calculated using inverse dynamics. The effect of posture and potential interactions with sex, side-stepping phases, and trailing/leading directions were analyzed using Pearson correlation and mixed-model ANOVAs.Result: A hip net muscle torque of extension, abduction and medial rotation was required to perform the exercise, regardless of phase and direction. The net muscle torque towards medial rotation required during the exercise was smaller (P < 0.001) in the upright (0.05-0.12 N m kg-1 m-1 across phases) compared to the squat posture (0.10-0.24 N m kg-1 m-1). In contrast, hip abductor torque was not affected by posture. When averaged across phases and directions, the normalized hip medial rotator muscle torque was highly correlated with knee flexion (r = 0.93, P < 0.001).Significance: The assumption that the side-stepping with the elastic band on the forefeet creates an external hip torque of medial rotation is erroneous. The resistance imposed to the hip during this exercise is consistent with the goal of strengthening the muscles that contribute to hip abduction and hip medial (not lateral) rotation. Changing the knee flexion angle is an effective way to manipulate hip rotator torque when prescribing this exercise in strength training and rehabilitation programs. [ABSTRACT FROM AUTHOR]

Background: The use of insoles, which is increasingly widespread, can promote changes in biomechanics during running.Research Question: Can the use of insoles with various patterns of infracapital support influence factors related to the dynamic stability of the lower limbs during running on a treadmill in recreational runners?Methods: This is controlled single-blind repeated measures. Static baropodometric data were collected, as well as kinematic data for the lower limbs and electromyographic data for the gluteus maximus and gluteus medius muscles, for twelve recreational runners on a treadmill using four models of insoles (neutral and with forefoot elements - infracapital bar).Results: Neutral insoles were able to reduce laterolateral displacement, increase the displacement of the mass to the posterior, and increase the lateral rotation of the left knee and medial rotation of the right hip. Insoles with a 2 mm total infracapital bar were able to move the mass to the posterior, increase laterolateral displacement and activate the gluteus medius. Insoles with a 2 mm medial infracapital bar were able to increase the displacement of the mass to the posterior, increase the adduction of left hip and the medial rotation of right hip, and activate the gluteus medius. Insoles with a 4 mm medial infracapital element were able to move the body mass to the posterior and to the left, increase laterolateral displacement, increase the adduction of left hip, the medial rotation of right hip and the abduction of right knee.Significance: The insoles evaluated in the present study were able to modify biomechanical variables of recreational runners related to dynamic stability during running on a treadmill and static baropodometric variables. [ABSTRACT FROM AUTHOR]

• The literature still debates the need for hip strengthening in LBP • Manual therapy and lumbar segmental stabilization are widely used by clinicians • Hip strengthening exercises added no benefits to a course of manual therapy and lumbar segmental stabilization for patients with LBP The literature is unclear on the need for hip strengthening in persons with low back pain (LBP). To investigate the effectiveness of hip strengthening exercises when added to manual therapy and lumbar segmental stabilization in patients with chronic nonspecific LBP. Seventy patients with chronic nonspecific LBP were randomly assigned to either the manual therapy and lumbar segmental stabilization group or the manual therapy and lumbar segmental stabilization plus specific hip strengthening group. A 10 cm visual analogue scale and the Rolland-Morris Questionnaire were the primary clinical outcome measures at baseline, at the end of treatment (posttreatment), and 6- and 12-months posttreatment. Hip strength and kinematics were measured as secondary outcomes. While within-group improvements in pain, disability, and hip extensors strength occurred in both groups, there were no significant between-group differences at posttreatment or follow-ups. Mean difference in changes in pain level between groups at posttreatment and at 6- and 12-month follow-up were 0.5 points (95% confidence interval [CI]: -0.5, 1.5), 0.3 points (95% CI: -0.9, 1.5), and 0.0 points (95% CI: -1.1, 1.1), respectively. The mean differences in changes in disability were 0.8 points (95% CI: -1.3, 2.7), 0.0 points (95% CI: -2.4, 2.4), and 0.4 points (95% CI: -2.0, 2.8), respectively. Finally, we did not observe any between-group differences for any of the other outcomes at any timepoint. The addition of specific hip strengthening does not appear to result in improved clinical outcomes for patients with nonspecific LBP. [ABSTRACT FROM AUTHOR]

• Hip extensors (HEX) torque was able to predict hip external rotators (HER) torque. • Both measures were strongly correlated in adults and older individuals. • There is no difference between directly measured and predicted values of HER torque. • The prediction equation was valid and accurate to estimate HER torque. The use of predictive equation of muscular torque can reduce physical effort and time spent during evaluation. To establish, validate, and test the accuracy of a prediction equation to estimate the hip external rotators (HER) torque in adults and older adults by means of hip extensors (HEX) torque measurement. Eighty-three healthy adults (development set) were assessed to test the association of HEX and HER torques and to establish the prediction equation. A separate 36 adults and 15 older adults (validation sets) were assessed to test the ability of the equation to estimate HER torque. Hip isometric strength was assessed by a handheld dynamometer. Simple linear regression analysis revealed that HEX torque was associated with HER torque (r = 0.80; p < 0.0001), resulting in the following prediction equation: HER torque = −0.02 + (0.58 * HEX torque). Paired t -test revealed no difference between directly measured and predicted values of HER torque in adults (mean difference = 0.02; 95% CI = −0.115, 0.072) and older adults (mean difference = 0.05; 95% CI = −0.02, 0.12). The HEX and HER torques were strongly correlated. The prediction equation was valid, accurate, and can be used to estimate HER muscle strength in healthy adults and older adults, requiring only the direct measurement of HEX torque. [ABSTRACT FROM AUTHOR]

Many studies have investigated the relationship between hypertension and its association with muscle health, showing controversial results on the subject. It is believed that high blood pressure can reduce the blood supply and cause damage to the arteries that supply areas of the motor cortex, responsible for muscle contraction and mobility, leading to a decay of functionality and reduced oxygen consumption and muscle strength. However, during aging there is a natural decrease in muscle mass, strength and quality, associated with the process of sarcopenia, although there are still difficulties identifying which factors are responsible for causing and worsening this process. In this context, it is believed that hypertension may play an important role in understanding this issue. compare isokinetic muscle function, muscle mass and gait speed among normotensive and hypertensive older adults. A cross-sectional observational study was conducted with 81 community-dwelling older adults selected by convenience. Participants were older people capable of walking without assistance and without cognitive alterations detectable by the Mini-Mental State Examination (MMSE). The diagnosis of arterial hypertension (independent variable) was made through the self-report of the participant´s previous medical diagnosis of arterial hypertension, validated by the record of using antihypertensive medication. The dependent variables of the study were: peak torque, muscle power, work by body weight and agonist-antagonist ratio of hip, knee and ankle (isokinetic dynamometry), handgrip strength (handgrip dynamometry), muscle mass (calf circumference) and usual gait speed at 10 meters. The dependent variables were compared between the groups of normotensive and hypertensive older adults by means of simple analyses and covariance adjusted for sex. most participants were female (51.9%), active (53.1%) and hypertensive (74%). In the simple analyses, it was observed that the hypertensive older group presented lower handgrip strength, lower mean peak torque of hip extensors and knee flexors, lower muscle power of knee flexors and extensors, lower work by body weight of hip flexors and knee extensors and lower knee agonist-antagonist ratio. However, in the analysis of covariance adjusted for sex, only in the knee agonist-antagonist ratio was found a statistically significant difference between the groups (40.64±9.01 vs 45.78±7.34; p=0.040). The study identified a lower knee agonist-antagonist ratio in hypertensive older adults when compared to normotensive patients. Our findings are linked to changes in muscle functioning that reflect uncoordinated activation of knee agonists and antagonists, although such changes cannot be fully explained by a significant reduction in strength. The understanding of hypertension and its impacts on muscle health contributes to a better understanding of the factors that cause and worsen the decline of muscle function in the older adults, in addition to being a potential contributor to the planning of health care strategies for the older people with a focus on the prevention and correct prescription of physical exercises. [ABSTRACT FROM AUTHOR]

The purpose of this study was to assess the association between hip flexor length and pelvic tilt or lumbar lordosis by quantifying the effect of stretching on pelvic tilt and lumbar lordosis. We quantified pelvic tilt and lumbar lordosis before and after a single session of passive hip flexor stretching in a sample of 23 male participants. Changes in hip flexor length were also characterized, using a Thomas test protocol to measure passive hip extension in supine lying. We investigated both the mean effect of the stretching protocol and potential correlations between changes in passive hip extension and changes in pelvic tilt or lumbar lordosis. Following the stretching protocol, there was a mean increase of 2.6° (P <.001) in passive hip extension and a corresponding mean reduction of 1.2° (P <.001) in anterior pelvic tilt. However, there was no change in lumbar lordosis, nor were there any meaningful correlations between change in passive hip extension and change in pelvic tilt or lumbar lordosis. The results suggest that hip muscle stretching may lead to immediate reductions in pelvic tilt during relaxed standing. Such stretching programs could play an important role in interventions designed to improve standing postural alignment. [ABSTRACT FROM AUTHOR]

Background: Falls among community-dwelling older adults are often triggered by uneven walkways. Joint coordination and its variability change with age and may place older adults at risk of falling. It is unclear how irregular surfaces impact lower-limb joint coordination and if such changes are exacerbated by aging.Research Question: To what extent do lower-limb inter-joint coordination and its variability, over flat and uneven brick walkways, differ between older and young healthy adults?Methods: A motion-capture system collected kinematic data from walking trials on flat and uneven walkways in seventeen older (72.0 ± 4.2 years) and eighteen younger (27.0 ± 4.7 years) healthy adults. Continuous relative phase analyses were performed for the Knee-Hip and Ankle-Knee joint pairs. Mean Absolute Relative Phase (MARP) quantified coordination amplitude. Deviation Phase (DP) quantified coordinative variability. Two-way mixed ANOVA's tested for effects of age, surface, and age × surface interactions.Results: Uneven surfaces prompted more in-phase MARP inter-joint coordination in adults during most gait phases (p ≤ 0.024). Age × surface interactions were observed during initial contact (Ankle-Knee: p = 0.021, Knee-Hip: p = 0.001) and loading response (Knee-Hip: p = 0.017), with post-hoc analyses showing coordination accentuated in older adults. Uneven surfaces induced higher DP in Knee-Hip (p = 0.017) and Ankle-Knee joint coupling (p < 0.001) during gait, largely independent of age. An age × surface interaction was observed during mid-swing (p = 0.050), with post-hoc analysis revealing increased variability in older adults.Significance: More in-phase and variable lower-limb gait behavior was observed on uneven walkways. These differences were accentuated in older adults during early stance phase (more tightly coordinated) and mid-swing (more variable). This may reflect a cautious gait strategy on challenging walkways to maintain stability and help prevent falls. [ABSTRACT FROM AUTHOR]

• Hip/knee flexion was associated with runners anterior reach distance in the modified star excursion balance test. • Hip flexion was associated with the posteromedial and knee flexion with the posterolateral reach. • Hip extensor strength was associated with posteromedial, posterolateral and composite reaches. • Trunk kinematics and strength were not associated with runners' performance in this test. Reduced trunk and lower limb movement and hip and trunk muscles weakness may compromise the athletes' performance on the modified Star Excursion Balance Test (mSEBT). To investigate the relationship of trunk and lower limb kinematics and strength with the performance on the mSEBT of runners at high risk of injury. Thirty-nine runners performed the mSEBT with the dominant limb as the support limb. An Inertial System was used to capture the trunk, hip, knee and ankle movement during the mSEBT. A handheld dynamometer was used to measure the strength of trunk extensors and lateral flexors muscles, and hip extensors, lateral rotators and abductors of the support limb. Multiple regressions were used to investigate if trunk and lower limbs kinematics and trunk and hip muscles strength are associated with performance during the mSEBT. Reduced hip flexion and greater knee flexion range of motion (ROM) were associated with anterior reach in the mSEBT (r2 = 0.45; p <.001), greater hip flexion ROM was associated with posteromedial reach (r2 = 0.15; p =.012) and greater knee flexion ROM was associated with posterolateral reach (r2 = 0.23; p <.001). Hip extensor strength was associated with posteromedial (r2 = 0.14; p =.017), posterolateral (r2 = 0.10; p =.038) and composite reaches (r2 = 0.16; p =.009). Hip and knee kinematics in the sagittal plane explained 15–45% of the runners' performance on the mSEBT and hip extensor strength explained 10–16% of the mSEBT performance. These findings provide useful information on the contribution of joints kinematics and strength when evaluating dynamic postural control in runners at high risk of injury. [ABSTRACT FROM AUTHOR]

Background: The ankle-strategy model, where the human body is modeled as a single inverted pendulum hinged at the ankle, has been used for decades to study the dynamics and the stability of the human upright posture (UP). However, the contribution of the hip joints is critical whenever postural disturbances are considered. To account for hip contribution, a double inverted pendulum (DIP) model rotating about the ankle and hip joints has been recently proposed in our previous work but experimental validation efforts are scarce.Method: In the present study, it is investigated whether the DIP model is able to reproduce the experimentally observed frequency spectrum of the ankle and hip joint kinematic for young and elderly subjects balancing on a compliant surface. The DIP model based and experimental kinematics are compared via Fourier analysis to obtain their corresponding amplitude spectrum density (ASD) functions. Quantitative comparisons of the ASD functions are accomplished through Bland-Altman (B&A) analysis, and Pearson correlation coefficient (PCC).Results: The DIP model can reproduce part of the experimental frequency spectrum of the ankle and hip joint angle position and velocity, especially for frequencies larger than 0.35 Hz. Moreover, the model captures the decaying behavior of the experimental ASD functions as frequency increases. With respect to joint angle velocities, the highest PCC between model-based and experimental ASD functions is found for the hip joint of elderly subjects. The B&A analysis shows that the zero-difference between model-based and experimental ASD functions lies between the 95 % confidence interval, especially for the joint angle position results. These suggest that the DIP model reproduces part of the experimentally observed frequency spectrum, which validates the model to study the dynamics and stability of the human upright posture. [ABSTRACT FROM AUTHOR]

Background: Altered gluteus minimus (GMin) activity has been identified in people with hip osteoarthritis (OA) during gait with some evidence of altered gluteus medius (GMed) activity in patients with advanced OA. It is not known whether these muscles also exhibit altered activity during other functional tasks.Research Question: Does gluteal muscle activity during stepping tasks differ between people with hip OA and healthy older adults?Methods: Participants included 20 people with unilateral hip OA and 20 age-and sex-matched controls. Muscle activity in the three segments within GMed and two segments of GMin were examined using intramuscular electromyography during step-up, step-down and side-step tasks.Results: Participants in the OA group demonstrated reduced muscle activity early in the step-up task and a later time to peak activity in most muscle segments. Greater activity was identified in anterior GMin in people with hip OA during the side-step task. A delay in time to peak activity was identified in most muscle segments in people with OA during the side-step task.Significance: For participants with OA, reduced activity in most muscle segments and increased time spent in double limb stance during the step-up task could reflect the decreased strength and pain associated with single limb stance on the affected limb. This study provides further evidence of altered function of the deep gluteal muscles in people with hip OA and highlights the importance of addressing these muscles in rehabilitation. [ABSTRACT FROM AUTHOR]

The purpose of this study was to quantify and report the intrarater and interrater reliability of hip internal rotation (IR) range of motion supine with the hip and knee at 90° of flexion and for the flexion-adduction-internal rotation (FADIR) test. Hip internal rotation measured in a lying supine position with the hip and knee at 90° of flexion revealed information on hip impairments. To date no simple quantification approach has been presented in this position; therefore, the FADIR test has not been quantified yet. Twenty participants (mean ± standard deviation [SD] age, 24.0 ± 2.1 years; 10 women and 10 men) without lower-limb or back pain were recruited. Three raters evaluated each participant during 2 testing sessions, 1 day apart. A built-in smartphone compass application was used to obtain the hip IR range of motion in both procedures. Mean (± SD) supine IR was 51.7° (± 9.7°) and 62.6° (± 11.4°) for men and women, respectively. Concerning the FADIR test, mean values were 41.8° (± 9.64°) and 50.1° (± 8.0°) for men and women, respectively. The mean intrarater and interrater reliability coefficients were 0.80 and 0.72 for hip IR and 0.75 and 0.40 for the FADIR test. The standard error of the mean ranged from 4.8° to 8.3° (minimal detectable difference [MDD], 13.3° to 22.9°) for hip IR and from 4.6° to 10.3° (MDD, 12.8° to 28.6°) for the FADIR test. Overall, the smartphone compass application is adequate to quantify hip IR in a lying supine position. However, the poor to moderate interrater reliability in the FADIR test and the size of the MDD values suggest that the FADIR test should be standardized. [ABSTRACT FROM AUTHOR]

Children with cerebral palsy experience movement disorders that influence gait stability. It is likely that gait stability further decreases when walking on uneven compared to even ground. Therefore, the aim of this study was to investigate gait on uneven ground in children with unilateral cerebral palsy. Twenty children with unilateral cerebral palsy and twenty typically developing children performed a three-dimensional gait analysis when walking on even and uneven ground. Spatio-temporal parameters, full-body joint kinematics and centre of mass displacements were compared. On uneven versus even ground, both groups showed decreased cadence, increased stance phase and double support time, increased toe clearance height, and increased knee and hip flexion during swing phase. Whereas only the typically developing children walked slower and had increased dorsiflexion and external foot progression during stance phase, only the patients showed increased stride width, increased elbow flexion (affected and non-affected side), and kept the centre of mass more medial when standing on the affected leg. Patients and healthy children use similar adaptation mechanisms when walking on uneven ground. Both groups increased the toe clearance height by increasing knee and hip flexion during swing. However, whereas patients enlarge their base of support by increasing stride width, healthy children do so by increasing their external foot progression angle. Furthermore, patients seem to feel more insecure and hold their arms in a position to prepare for falls on uneven ground. They also do not compensate with their non-affected side for their affected side on uneven ground. • Adaptive mechanisms when walking on uneven ground in patients with unilateral cerebral palsy • Patients and healthy children show similar adaptive mechanisms on uneven ground. • Different strategies to maintain dynamic stability on uneven ground were discovered. • Patients do not compensate with their non-affected side for their affected side on uneven ground. [ABSTRACT FROM AUTHOR]

The aim of this systematic review with meta-analysis was to determine the change in gait biomechanics after total ankle replacement and ankle arthrodesis for end-stage osteoarthritis. Electronic databases were searched up until May 2019. Peer-reviewed journal studies including adult participants suffering from end-stage ankle osteoarthritis and reporting pre- and post-operative kinematics, kinetics and spatio-temporal effects of total ankle replacement and ankle arthrodesis during walking were included with a minimum of 12 months follow-up. Seventeen suitable studies were identified and assessed according to methodological and biomechanical qualities. Meta-analysis was performed by calculating the effect size using standard mean differences between pre- and post-operative gait status. Seventeen studies with a total of 883 patients were included. Meta-analysis revealed moderate evidence of an improvement in lower limb kinematics, kinetics and spatio-temporal parameters after total ankle replacement. Moderate evidence indicated an increase in ankle moment, hip range of motion and walking speed after ankle arthrodesis. The currently available evidence base of research papers evaluating changes in gait biomechanics after total ankle replacement and ankle arthrodesis is limited by a lack of prospective research, low sample sizes and heterogeneity in the patho-etiology of ankle osteoarthritis. Following total ankle replacement, improvements were demonstrated for spatio-temporal, kinematic and kinetic gait patterns compared to the pre-operative measures. Improvements in gait mechanics after ankle arthrodesis were limited to walking speed and ankle moment. Increased hip range of motion after ankle arthrodesis could represent a sign of compensation for the lack of ankle motion. • Moderate evidence to suggest that lower extremity biomechanics improved after total ankle replacement. • Moderate evidence to suggest that total ankle replacement improves pre-operative ankle range of motion by 3°. • No difference in outcomes between fixed- versus mobile-bearing prosthesis • Ankle moment, hip range of motion and walking speed increased after ankle arthrodesis. [ABSTRACT FROM AUTHOR]

Background: Distance running fitness is commonly assessed using metabolic testing (MT). During MT, the runner must wear a mask that covers the nose and mouth. It is unclear if this increased challenge alters running kinematics and/or stride-to-stride variability (SSV). In this study we thoroughly assess the sagittal plane lower body joint angles.Research Question: Are there significant differences between standard treadmill running kinematics and those collected during MT?Methods: Twenty recreational runners participated (34.8 ± 10.0 years; 20+ miles per week). Six Vicon Bonita cameras were used to collect kinematic data (200 Hz). A metabolic cart (Parvo Medics TrueOne 2400) was used for heart rate (HR) collection and testing. Participants ran 4 × 4 min at preferred pace: 2 control runs (CON) and 2 MT runs. Ten strides were used to generate average stance and swing joint angle plots. The phase plots were compared for CON and MT and mean difference scores were calculated (to determine the kinematic change). SSV was determined by assessing the standard deviations among the 10 strides. Repeated measures ANOVA was used to test for significant differences among CON and MT trials. Reliability was assessed for 8 discrete joint angles using ICC analysis.Results: There were no significant differences between CON and MT for both the joint angle plot comparisons and SSV. For the discrete kinematic measures, ICC scores were strong (0.89-0.99) between CON and MT. During MT, there were slight increases (p < 0.01) in HR (145 ± 14 vs. 147 ± 14) and RPE (10.4 ± 1.5 vs. 11.4 ± 1.5).Significance: Results from this study support the validity of simultaneously conducting a kinematic and MT analysis. However, clinicians and performance coaches should be aware that 1) MT is slightly more physiologically demanding than CON and 2) approaches from this study can be used during individual assessments to confirm that kinematics are similar (between CON and MT). [ABSTRACT FROM AUTHOR]

Background: Hip external rotation stiffness, midfoot passive mechanical resistance and foot alignment may influence on ankle, knee and hip movement in the frontal and transverse planes during gait.Research Question: Are hip stiffness, midfoot mechanical resistance and foot alignment associated with ankle, knee and hip kinematics during gait?Methods: Hip stiffness, midfoot mechanical resistance, and foot alignment of thirty healthy participants (18 females and 12 males) with average age of 25.4 years were measured. In addition, lower limb kinematic data during the stance phase of gait were collected with the Qualisys System (Oqus 7+). Stepwise multiple linear regressions were performed to identify if hip stiffness, midfoot torque, midfoot stiffness and foot alignment were associated with hip and knee movement in the transverse plane and ankle movement in the frontal plane with α = 0.05.Results: Reduced midfoot torque was associated with higher hip range of motion (ROM) in the transverse plane (r2 = 0.18), reduced hip stiffness was associated with higher peak hip internal rotation (r2 = 0.16) and higher ROM in the frontal plane (r2 = 0.14), reduced midfoot stiffness was associated with higher peak knee internal rotation (r2 = 0.14) and increased midfoot torque and midfoot stiffness were associated with higher peak knee external rotation (r2 = 0.36).Significance: These findings demonstrated that individuals with reduced hip and midfoot stiffness have higher hip and knee internal rotation and higher ankle eversion during the stance phase of gait. On the other hand, individuals with increased midfoot torque and stiffness have higher knee external rotation. These relationships can be explained by the coupling between ankle movements in the frontal plane and knee and hip movements in the transverse plane. Finally, this study suggests that midfoot passive mechanical resistance and hip stiffness should be assessed in individuals presenting altered ankle, knee and hip movement during gait. [ABSTRACT FROM AUTHOR]

Background: One in four pregnant women falls at least once during her pregnancy. During pregnancy, the body undergoes tremendous vascular, hormonal, physiological, and psychological changes to accommodate the growing fetus. The pregnancy-induced mass gain of 10 to 25 kg is not evenly distributed and results in a large change in mass distribution and shift in segmental centers of mass. To accurately understand how the change in mass distribution leads to an increase in fall events, a musculoskeletal model of the pregnant body is necessary. Generic musculoskeletal models cannot accurately represent the morphology of pregnant women and the study of postural stability of pregnant women is limited by the lack of adapted musculoskeletal models.Research Question: Could a model reflecting the change in segmental inertia during pregnancy explain the pregnancy-related risk of falling?Methods: We built a musculoskeletal model of the pregnant women, combining literature anthropomorphic measurements with generic models. We optimized the dimensions of the anthropomorphic model shapes to fit the average measurements of 25 pregnant women. The mass, center of mass, and inertia of each segment are then computed throughout pregnancy. Finally, the stance phase of a gait cycle was modeled using the pregnancy-specific and the generic models. The ankle, knee, hip and lumbar joint moments during gait were compared between the two models.Results: The built musculoskeletal model of the pregnant woman includes changes in mass and geometry of the thorax, pelvis, thighs, and legs. The model reproduces the change in lumbar curvature during pregnancy. Gait simulation results show a limited impact of pregnancy on the ankle, knee, and hip moment, but a large impact on the lumbar moment.Significance: Such a musculoskeletal model will help elucidate the mechanisms leading to falls or low back pain during pregnancy. [ABSTRACT FROM AUTHOR]

Background: Fatigue is an essential component of distance running. Still, little is known about the effects of running induced fatigue on three-dimensional lower extremity joint movement, in particular in the frontal and transverse planes of motion.Research Question: How are non-sagittal plane lower extremity joint kinematics of runners altered during a 10 km treadmill run with near-maximum effort?Methods: In a cross-sectional study design, we captured three-dimensional kinematics and kinetics at regular intervals throughout a 10 km treadmill run in 24 male participants (subdivided into a competitive and recreational runner group) at a speed corresponding to 105 % of their season-best time. We calculated average and peak joint angles at the hip, knee and ankle during the stance phase.Results: We observed peak deviations of 3.5°, 3° and 5° for the hip (more adduction), knee (more abduction) and ankle (more eversion) in the frontal plane when comparing the final (10 km) with the first (0 km) measurement. At the end of the run peak knee internal rotation angles increased significantly (up to 3° difference). Running with a more abducted knee joint and with a higher demand for hip abductor muscles in the unfatigued state was related to greater fatigue-induced changes of joint kinematics at the knee and hip.Significance: The fatigue related change of non-sagittal joint kinematics needs to be considered when addressing risk factors for running-related injuries, when designing shoe interventions as well as strengthening and gait retraining protocols for runners. We speculate that strengthening ankle invertors and hip abductors and monitoring the dynamic leg axis during running appear to be promising in preventing fatigue induced alterations of non-sagittal joint kinematics. [ABSTRACT FROM AUTHOR]

Primary aim of this study is to investigate if Hip-Knee-Ankle angle, measured in the coronal plane, changes with knee flexion after total knee arthroplasty. The secondary aim is to assess the relationship between Hip-Knee-Ankle during knee flexion and clinical outcome at mid-term follow up. 334 computer assisted total knee arthroplasties were retrospectively evaluated. A total of 233 patients were available for assessment of clinical outcomes at last follow up (mean 35 months). Hip-Knee-Ankle angle at different degrees of knee flexion and components' alignment were recorded intraoperatively. Patients were stratified based on the preoperative alignment: 202 varus knees, 99 neutral knees, and 33 valgus knees. In the varus knee group, 146 patients (89%) maintained a neutral overall limb alignment when flexed to 20°, 118 (72%) remained neutrally aligned at 45° and 92 (54%) at 90°. In valgus knee group, 26 (90%) remained neutrally aligned at 20°, 22 (75%) at 45° and 16 (55%) at 90°. In neutrally-aligned knee group, 88 (96%) remained neutrally aligned at 20°, 73 (79%) at 45° and 61 (66%) at 90°. Femoral component external rotation was correlated with varus alignment in flexion. Good outcomes were reported in 181 (78%) cases, fair results in 28 (12%) cases, poor results in 24 (10%) of cases. Poor results were not correlated to Hip-Knee-Ankle angle at different knee flexion angles. This study demonstrates that intraoperative Hip-Knee-Ankle angle changes as the knee moves into deeper flexion. However, neutral Hip-Knee-Ankle through the range of motion does not correlate with superior outcomes. • Hip-Knee-Ankle angle changes during flexion in total knee arthroplasty. • Clinical outcome is not affected by mechanical axis at different degrees of flexion. • This study questions the importance of neutral mechanical alignment in extension. [ABSTRACT FROM AUTHOR]

Femoroacetabular acetabular impingement syndrome consists of abnormal hip joint morphology resulting in painful hip joint impingement. Hip arthroscopy corrects the abnormal morphology and reduces clinical symptoms associated with femoroacetabular impingement syndrome yet the effects of hip arthroscopy on gait mechanics and cartilage health are not well understood. Ten femoroacetabular impingement syndrome patients and 10 matched asymptomatic controls underwent gait analysis consisting of three-dimensional hip joint kinematics and kinetics. Femoroacetabular impingement syndrome patients underwent gait analysis and quantitative magnetic resonance imaging of the surgical hip joint before and seven months post-surgery. Patient reported outcomes were obtained from all study participants and were used to quantify hip joint pain, function and quality of life. Prior to surgery, femoroacetabular impingement syndrome patients demonstrated hip joint kinematics or kinetics as the control group. After surgery, femoroacetabular impingement syndrome patients exhibited improved patient reported outcomes, similar hip joint kinematic patterns, increased hip flexion and decreased hip extension moment impulses within the surgical limb. The femoroacetabular impingement syndrome patients that ambulated with increased HFMI post-surgery demonstrated a decrease in femoral cartilage T1ρ and T2 values. Femoroacetabular impingement syndrome patients exhibited improved clinical symptoms yet ambulated with altered sagittal plane hip joint loading after hip arthroscopy. Increased hip flexion moment impulse post-surgery was associated with improved cartilage health within the surgical limb. These study findings suggest that sagittal plane hip joint loading at short-term follow-up after hip arthroscopy is associated with cartilage health and may be an important biomechanical parameter in post-operative rehabilitation programs. • Pre- & post-surgical hip joint kinematics are similar between controls & patients. • Hip flexion moment impulse increased in the patients' surgical limb after surgery. • Increased hip joint loading (post-surgery) was related to improved cartilage health. [ABSTRACT FROM AUTHOR]

Osteoarthritis after anterior cruciate ligament reconstruction has been linked with changes in gait. Individuals with reconstruction demonstrate gait changes after exercise, however there is no information on altered gait after exercise based on sex. The purpose of this study was to examine the association of sex on changes in running gait after exercise in individuals with reconstruction compared to healthy. Forty females (22 reconstructed) and 22 men (11 reconstructed) ran before and after exercise. Triplanar lower extremity kinematics and kinetics were measured on the involved limb. Data were reduced to 0–100% of gait. Change scores were calculated for each 1% with 90% confidence intervals. Mean differences were calculated for all significant differences. After exercise, females with reconstruction increased knee valgus (1.81°), knee external rotation (2.02°), lateral trunk flexion (1.24°) and trunk rotation (2.15°) compared to healthy females. Females with reconstruction increased knee extension moment (0.07 Nm/kg), knee abduction moment (0.08 Nm/kg), hip extension moment (0.14 Nm/kg) and hip internal rotation moment (0.04 Nm/kg) compared to healthy females. After exercise, males with reconstruction decreased knee varus (−4.83°), hip adduction (−1.99°), and hip internal rotation (−4.44°), however increased lateral trunk flexion (1.94°) compared to healthy males. Males with reconstruction increased knee extension moment (0.07 Nm/kg), knee adduction moment (0.31 Nm/kg), knee internal rotation moment (0.13 Nm/kg), hip flexion moment (0.17 Nm/kg), and hip external rotation moment (0.05 Nm/kg) compared to healthy males. Males with reconstruction increased hip loading while women with reconstruction increased trunk motion post-exercise. Sex should be considered when evaluating response to exercise after reconstruction. • We compared gait after exercise after knee ligament reconstruction between sexes. • Changes in sagittal kinematics after exercise are similar to healthy controls. • Women with reconstruction increased frontal and transverse motion post-exercise. • Men maintained pre-exercise frontal and transverse plane loading post-exercise. [ABSTRACT FROM AUTHOR]

Repeated exposures to larger lateral trunk-pelvic motion and features of knee joint loading likely influence the onset of low back pain and knee osteoarthritis among persons with lower-limb amputation. Decreased hip abductor strength can also influence frontal plane trunk-pelvic motion and knee moments; however, it is unclear how these are inter-related post-amputation. Twenty-four participants with unilateral lower-limb amputation (14 transtibial; 10 transfemoral) and eight uninjured controls walked at 1.3 m/s while full-body biomechanical data were captured. Multiple linear regression and Cohen's f 2 predicted (P < 0.05) the influences of mediolateral trunk and pelvic ranges of motion and angular accelerations, and bilateral isometric hip abductor strength on peak (intact) knee adduction moment and loading rate. There were no group differences in hip strength, peak knee adduction moment or pelvis acceleration (p > 0.06). The combination of hip strength, and mediolateral trunk and pelvic motion did not predict (F (5,29) = 2.53, p = 0.06, adjusted R2 = 0.27, f 2 = 0.08) peak knee adduction moment. However, the combination of hip strength and trunk and pelvis acceleration predicted knee adduction moment loading rate (F (7,29) = 3.59, p = 0.008, adjusted R2 = 0.45, f 2 = 0.25), with peak trunk acceleration (β = 0.72, p = 0.008) and intact hip strength (β = 0.78, p = 0.008) significantly contributing to the model. These data suggest increased hip abductor strength counteracts increased lateral trunk acceleration, concomitantly influencing the rate at which the ground reaction force vector loads the intact knee joint. Persons with lower-limb amputation perhaps compensate for increased intact limb loading by increasing trunk motion, thereby increasing demand on hip abductors to attenuate this preferential loading. • Hip abductor strength influenced moment loading rate in intact knees rather than peak moment. • Frontal plane trunk motion is associated with knee adduction moment loading rate. • No differences by presence or level of limb loss (transtibial vs. transfemoral) • There is interplay between proximal and distal outcomes after limb loss. [ABSTRACT FROM AUTHOR]

Knee osteoarthritis tends to modify the kinematics and kinetics of the sit-to-stand task. However, it is not clear whether the different degrees of knee osteoarthritis differentiate regarding these aspects. The objective was to identify if the trunk flexion, lower limb kinetics, total support moment, and individual joint contributions to the total support moment during the sit-to-stand task are different between patients with mild and moderate knee osteoarthritis. Sixty-two participants were grouped as follows: moderate knee osteoarthritis (n = 16), mild knee osteoarthritis (n = 25), and controls (n = 21). The participants performed a sit-to-stand task, which was analyzed using a 3D-motion system and a force plate. The three phases of the sit-to-stand task were analyzed. During Phase 1 , the moderate osteoarthritis group decreased the total support moment (P = 0.012). During Phase 2 , the moderate osteoarthritis group showed higher trunk flexion (P = 0.023) and lower internal hip and knee extension moments (P ≤ 0.001 and P ≤ 0.040, respectively) when compared to controls. Also in Phase 2 , both the mild and moderate groups used lower total support moment (P = 0.019, and P ≤ 0.001, respectively). When compared to the controls and mild osteoarthritis group , those with moderate osteoarthritis presented higher hip joint contribution to the total support moment (P ≤ 0.001 and P = 0.006, respectively) as well as lower knee joint contribution (P ≤ 0.003 and P = 0,013, respectively). Those with moderate osteoarthritis showed modified sit-to-stand movement pattern. While in Phase 3 a higher contribution of the hip joint to the total support moment was observed, during previous phases the individuals were able to decrease the load on the knee without influencing the lower limb load distribution. • Those with different degrees of knee osteoarthritis rise from the chair differently. • Moderate osteoarthritis presented an intersegmental incoordination at the end of the task. • Individuals with moderate osteoarthritis stand up using higher trunk flexion. • Individuals with mild/moderate osteoarthritis stand up with lower knee moment in the sagittal plane. [ABSTRACT FROM AUTHOR]

Patients with acetabular dysplasia have an abnormal acetabular geometry which results in insufficient coverage of the femoral head. This coverage deficiency reduces contact surfaces within the joint, accelerating the wear of the articular cartilage and predisposing patients to early osteoarthritis. Periacetabular osteotomy is a surgical treatment of acetabular dysplasia that aims to reorient the acetabulum relative to the femoral head, increasing coverage. Pelvic kinematics and lower limbs joint kinematics and kinetics during the stance phase of gait were recorded using a 3D motion capture system and force plates, then compared pre- to post- and between limbs with a repeated measures 2-way ANOVA. Radiographic measurements and gait parameters were compared pre- to post-surgery using a t -test for dependant samples. To identify predictors of pelvic symmetry improvements during gait, a multivariate analysis was performed using a forward stepwise linear regression. Radiographic measurements improved for all participants while gait parameters remained unchanged. Hip flexion symmetry was improved following surgery. The external rotation moment of the healthy hip was reduced after surgery (−29%) resulting in increased asymmetry. Pelvic tilt was significantly greater on the affected side (+0.5°) during the loading response, and the difference tended to be greater after surgery (+0.8°). Unilaterally affected dysplastic patients have an asymmetrical gait pattern that is only partially corrected by periacetabular osteotomy even when radiographic and clinical targets are met. Differences between the limbs could be explained in part by a learned antalgic pattern and muscle weaknesses leading to complex compensation mechanisms. • Gait parameters remain unchanged after periacetabular osteotomy. • Periacetabular osteotomy has mixed effect on limbs kinetics and kinematics symmetry during gait. • Dynamic pelvic tilt increases following surgery. [ABSTRACT FROM AUTHOR]

The treatment strategy for developmental dysplasia of the hip is determined based on the lateral center-edge angle. Nonetheless, an evaluation of joint instability may be important in determining the treatment strategy. This study classified the displacement patterns of the femoral head center during hip abduction. Ten patients with borderline developmental dysplasia of the hip, 10 patients with developmental dysplasia of the hip, and 10 patients with normal hips were analyzed. Image matching was performed using X-ray images of hip abduction with a three-dimensional hip model. The displacement of the femoral head center and its trajectory length were measured. A cluster analysis was conducted to classify the displacement pattern of the femoral head center, and trajectory lengths were compared. Displacement was classified into three patterns: medialization, hinge abduction, and centering. Patients with borderline developmental hip dysplasia exhibited all three patterns. Almost all patients with developmental dysplasia of the hip showed medialization and hinge abduction, whereas all normal patients had the centering type. The mean trajectory length indices for the medialization and hinge abduction types were significantly longer than those for the centering type (P = 0.01 and P = 0.016, respectively). Borderline developmental dysplasia of the hip is a heterogeneous condition characterized by varying hip instability levels. Our findings suggest that uniform evaluation based on the lateral center-edge angle is inappropriate and that joint instability must be evaluated in each patient with borderline developmental dysplasia of the hip. • We evaluated joint instability in patients with borderline developmental dysplasia of the hip. • The displacement was classified into three patterns: medialization, hinge action, and centering. • The medialization and hinge action type were considered to represent joint instability. • Borderline Developmental dysplasia of the hip includes cases with and without joint instability. • The treatment of borderline-developmental dysplasia of the hip may be dependent on the degree of joint instability. [ABSTRACT FROM AUTHOR]

Dance-based exergaming has exhibited efficacy in people with chronic stroke, it is beneficial to advance towards independent self-training to increase long-term compliance, and cost effectiveness through safety harness devices. Thus, the purpose of the study was to investigate people with chronic stroke's dance-movement kinematics to different types of assistance, namely no assistance, safety harness assistance, and contact guard assistance with gait belt. Community-dwelling people with chronic stroke (n = 10) participated in the study. Seven inertial sensors were used to capture their dance movements with three songs slow, medium, and fast pace. Three trials were recorded for each dance and the mean values of variables were used for analysis. A customized MATLAB code generated joint angle excursions (difference between the maximum and minimum angle peaks) of the hip, knee, and ankle in the sagittal plane. The results exhibited decreased joint angle excursions in no assistance condition in comparison to safety harness assistance and contact guard assistance conditions for all song paces (p < 0.05). The safety harness , and contact guard assistance condition exhibited similar levels of joint angle excursions for the all the conditions, except significantly higher hip (slow, and fast pace) (p < 0.05), and ankle (medium pace) (p < 0.05) joint angle excursions in contact guard assistance in comparison to safety harness assistance . The study represents the joint angle excursions that are influenced by different conditions in chronic stroke. Future studies, should evaluate feasibility of safety harness augmented dance-based exergaming in home-setting among chronic stroke. [Display omitted] • Lower extremity kinematics with safety harness exhibits safety and feasibility. • Safety harness, and contact guard assistance conditions facilitated equal levels of joint angle excursions. • Safety harness helps implement dance-based exergaming in home-setting in stroke. [ABSTRACT FROM AUTHOR]

Background: Military personnel don body borne loads that produce maladaptive lower limb biomechanics, increasing risk of musculoskeletal injury during common training tasks. Female personnel have over twice the injury risk as males, but it is unknown if a sex dimorphism in lower limb biomechanics exists during common training-related tasks.Research Question: To determine whether lower limb biomechanics exhibited during a single-leg cut with military body borne loads differ between sexes.Methods: Sixteen females and 20 males had lower limb biomechanics quantified during five single-leg cuts off each limb with four loads (20, 25, 30 and 35 kg). Each cut required participants run 4 m/s, before planting their foot on a force platform and cut 45° towards the opposite limb. Lower limb biomechanics related to musculoskeletal injury were submitted to a repeated measures ANOVA to test for main and interaction effects of load, sex, and limb.Results: During the cut, load increased peak proximal anterior tibial shear force (p < 0.001) and peak hip flexion (p = 0.010) and knee abduction (p = 0.045) moments, but decreased peak knee flexion angle (p = 0.032). Females exhibited greater peak proximal anterior tibial shear (p = 0.014), and peak hip adduction (p < 0.001) and knee external rotation (p = 0.001) moment than males. Dominant limb exhibited larger peak hip adduction (p = 0.002); whereas, the non-dominant limb exhibited greater peak hip internal (p = 0.002) and knee external (p = 0.007) rotation moments. Only the non-dominant limb increased peak knee abduction moment (p = 0.001) with additional load.Significance: During the cut, adding body borne load produced maladaptive biomechanics that may increase knee musculoskeletal injury risk. Load increased peak proximal tibial shear and potential strain of knee's soft-tissues. Females exhibited a sex dimorphism in lower limb biomechanics that may further elevate their injury risk. Both limbs exhibited biomechanics that may increase injury risk, but only the non-dominant limb further increased injury risk with load. [ABSTRACT FROM AUTHOR]

Background: Excessive foot pronation during running in individuals with foot varus alignment may be reduced by medially wedged insoles.Research Question: This study investigated the effects of a medially wedged insole at the forefoot and at the rearfoot on the lower limbs angles and internal moments of runners with excessive foot pronation and foot varus alignment.Methods: Kinematic and kinetic data of 19 runners (11 females and 8 males) were collected while they ran wearing flat (control condition) and medially wedged insoles (insole condition). Both insoles had arch support. We used principal component analysis for data reduction and dependent t-test to compare differences between conditions.Results: The insole condition reduced ankle eversion (p = 0.003; effect size = 0.63); reduced knee range of motion in the transverse plane (p = 0.012; effect size = 0.55); increased knee range of motion in the frontal plane in early stance and had earlier knee adduction peak (p = 0.018; effect size = 0.52); reduced hip range of motion in the transverse plane (p = 0.031; effect size = 0.48); reduced hip adduction (p = 0.024; effect size = 0.50); reduced ankle inversion moment (p = 0.012; effect size = 0.55); and increased the difference between the knee internal rotation moment in early stance and midstance (p = 0.012; effect size = 0.55).Significance: Insoles with 7˚ medial wedges at the forefoot and rearfoot are able to modify motion and moments patterns that are related to lower limb injuries in runners with increased foot pronation and foot varus alignment with some non-desired effects on the knee motion in the frontal plane. [ABSTRACT FROM AUTHOR]

Deep hip muscle retraining is a common objective of non-operative management for femoroacetabular impingement (FAI) syndrome. These muscles are considered to have an important role in hip joint stabilization, however, it is unclear whether their function is altered in the presence of hip pathology. This exploratory study aimed to investigate activation patterns of the hip muscles during two squatting tasks in individuals with and without FAI syndrome. Fifteen individuals with FAI syndrome (symptoms, clinical examination and imaging) and 14 age- and sex-comparable healthy controls underwent testing. Intramuscular fine-wire and surface electrodes recorded electromyographic activity of selected deep and superficial hip muscles during the squatting tasks. Activation patterns from individual muscles were compared between-groups using a wavelet-based linear mixed effects model (P < 0.05). There were no between-group differences for squat depth or speed during descent or ascent for either task. Participants with FAI syndrome exhibited patterns of activation that differed significantly to controls across all muscles (P < 0.05) when squatting using their preferred strategy. Unlike controls, participants with FAI syndrome exhibited a pattern of activation for obturator internus during descent that was similar in amplitude to ascent, despite the contrasting contraction type (i.e. eccentric vs concentric). Individuals with FAI syndrome appear to implement a protective strategy as the hip descends towards the impingement position. Future studies should examine patients prospectively to establish whether these strategies are counterproductive for pathology and warrant rehabilitation. • Hip muscle activation is altered during squatting in FAI syndrome. • Activation of external rotators is similar in descent and ascent in FAI syndrome. • Neuromuscular strategy appears protective as hip approaches impingement. • Unclear whether these strategies are counterproductive and warrant rehabilitation. [ABSTRACT FROM AUTHOR]

Excess body mass is thought to be a major cause of altered biomechanics in obesity, but the effects of body mass distribution in biomechanics during daily living tasks are unknown. The purpose of this study was to determine how increasing body mass centrally and peripherally affects lower extremity kinematics, kinetics, and muscle activation when transitioning from stair descent to level gait. Fifteen normal weight volunteers descended a staircase at a self-selected pace under unloaded, centrally loaded, and peripherally loaded conditions. Spatial-temporal gait characteristics and lower extremity joint kinematics, kinetics, and mean electromyography amplitude were calculated using 3D motion analysis. Both central and peripheral loading reduced gait velocity. Peripheral loading increased time spent in stance phase, increased step width, and reduced step length. At the hip joint, peripheral loading reduced peak hip extension and adduction angle. Conversely, central loading reduced peak hip flexor moment. Both central and peripheral loading increased peak knee flexion angle, but only peripheral loading increased peak knee extensor moment. Central and peripheral loading increased mean electromyography amplitude of the medial gastrocnemius, but only peripheral loading increased mean electromyography amplitude of the semitendinosus and the vastus medialis. Increasing mass centrally and peripherally differently affects spatial-temporal gait characteristics and lower extremity joint kinematics, kinetics, and electromyography when transitioning from stair descent to level gait. Body mass distribution may be an important factor for obesity-induced biomechanical alterations and should be considered when developing biomechanical models of obesity. • Increasing body mass, regardless of distribution, reduces stair descent velocity • Adding mass to thighs, but not the trunk, negatively impacts spatial-temporal parameters during stair transition • Hip and knee kinematics and kinetics are differently affected by adding mass to the trunk and thighs • Adding mass to the thighs, but not the trunk, increases EMG activity of the knee flexors and extensors • Distribution of mass is an important determinant of kinematics, kinetics, and muscle recruitment during stair transitions [ABSTRACT FROM AUTHOR]

The aim of the current study was to assess movement strategies during a single leg balance in chronic ankle instability individuals with unstable postural control strategy identified by Nyquist and Bode analyses in conjunction with sample entropy. Thirty-three participants with self-reported chronic ankle instability and 22 healthy controls performed single-leg eyes closed static balance trials. The sagittal and frontal plane kinematics in the lower extremity and trunk as well as center of pressure trajectories were recorded during three, 20-second trials. The Nyquist and Bode stability analyses, which classify center of pressure waveforms as stable based on the resulting gain and phase margins, were performed to identify the presence of postural control deficits. Sample entropy was implemented to analyze movement strategies during the task. Based on the Nyquist and Bode stability analyses, we included 19 out of 33 chronic ankle instability participants with unstable postural control strategy and 16 out of 22 controls with stable postural control strategy in the final analyses. Chronic ankle instability participants demonstrated a significantly lower sample entropy value in sagittal and frontal plane trunk kinematics and sagittal plane hip kinematics compared to the controls. No between-group differences existed in other kinematic measures. The lower sample entropy values in participants with chronic ankle instability indicates that those with postural control deficits may increase reliance on the trunk and hip joint contributions to the maintenance of postural control, reflecting changes in the sensorimotor constraints on movement patterns during the task. • Ankle and postural instability were associated with decreased kinematic variability. • Ankle and postural instability were related to a hip-and-trunk-locked movement. • Postural instability is critical prior to determining altered movement strategies. • Identifying the disablement exhibited is critical to design rehabilitation programs. • Nyquist/Bode criteria are a potential tool for ankle instability homogeneity. [ABSTRACT FROM AUTHOR]

Background: Maintaining body centre of mass (CoM) lowering velocity within manageable/safe limits during stair descent can be problematic for older individuals due to reduced ranges of motion at the involved joints (ankle and knee) and a reduced ability to generate adequate joint moments at the extremes in joint ranges of motion. These problems are likely to magnify in circumstances where the distance of lowering increases, or when misjudging the height of lowering.Research Question: How does a 50% increase in standard stair riser-height affect control of CoM velocity and acceleration of older people during stair descent?Methods: Fifteen older (75 ± 3 years) and seventeen young (25 ± 4 years) healthy adults descended a 4-step staircase, at two riser-heights: 170 mm, 255 mm. Changes in peak vertical CoM acceleration and velocity, and lower-limb joint kinetics (moments, work) during landing and lowering phases of stair descent were assessed using a mixed-design repeated measures analysis of variance.Results: Peak CoM accelerations and velocities during landing and lowering were lower in older compared to young adults and increased in both groups at 255 mm riser-height. Duration of lowering also increased, particularly for older adults. Peak ankle moments during landing and lowering, which were lower in older compared to young adults, increased when descending from 255 mm riser-height, whilst the peak knee moment reduced. Both groups produced increased landing-limb negative (eccentric) ankle joint work when descending from 255 mm, but increases were greater for older adults (87.8%) compared to young (76.1%).Significance: Descending stairs became more challenging in both age groups as riser-height increased. Older adults adopted a strategy of reducing CoM velocity to lessen the eccentric landing demands. In both groups, but more so older adults, there was a greater reliance on using leading-limb eccentric plantarflexion at 255 mm riser-height compared to 170 mm, to arrest/control increased downward CoM velocity and acceleration during landing. [ABSTRACT FROM AUTHOR]

Background: Approximately 25% of orthopedic knee conditions are related to patellofemoral pain (PFP), with young women being the most affected. It is thought that this condition is associated with modifications in the kinematics and muscle control patterns of the lower limb during weight-bearing support activities, which increases femur movement under the patella.Objectives: To compare kinematics and muscle induced acceleration patterns between PFP subjects and healthy controls during the preparation phase of the single leg triple hop test.Study Design: Biomechanical analysis was performed using OpenSim. Ten physically active women (23.2 ± 4 years, 59.3 ± 5.8 kg, and 1.63 ± 0.06 m) with no history of lower limb injury (CG) and 11 volunteers (23.5 ± 2 years, 55.4 ± 4.9 kg, and 1.66 ± 0.04 m) with PFP (PFPG) were recruited. The participants performed a series of single leg triple hop tests while the ground reaction forces and kinematic data were recorded.Results: Vector field statistical analysis indicated increased lumbar extension, anterior pelvic tilt, contralateral pelvic drop, and lower induced accelerations from the core and hip muscles in PFPG.Conclusion: PFP volunteers presented with alterations in lumbar muscle control associated with a possible compensatory pelvic strategy to minimize knee extensor moment. [ABSTRACT FROM AUTHOR]

• Physical therapists routinely examine strength, range of motion and muscle flexibility of the hip(s) for individuals with low back pain. • Physical therapists often provide strengthening and flexibility interventions targeting the hips for individuals with low back pain. • Post-professional fellowship training as a physical therapist changed intervention selection to include more joint manual therapy and less muscle flexibility and modality usage. The main research aims were to investigate whether physical therapists are examining the hip(s) in individuals with a primary complaint of low back pain (LBP) and if so, the interventions being provided that target the hip(s). An anonymous electronic survey was distributed to the membership of the American Physical Therapy Association Orthopaedic and Sports Sections, as well as that of the American Academy of Orthopaedic Manual Physical Therapists. Participant demographics and survey responses were analyzed using descriptive statistics. Associations between variables were examined using chi-square analysis. The estimated response rate was 18.4% (n = 1163, mean age 40.5 ± 11.4 years). The majority of respondents (91%, n = 1059) reported they always or most of the time examined the hip(s) in individuals with LBP. The most common examination items utilized were hip strength testing (94%, n = 948), passive range of motion (91%, n = 921) and muscle flexibility testing (90%, n = 906). The most common interventions included hip strengthening (94%, n = 866) and hip flexibility exercises (90%, n = 814). Respondents enrolled in or having completed a post-professional fellowship were more likely to utilize hip joint manual therapy techniques (x 2 = 25.3, p = <0.001) and less likely to prescribe hip flexibility exercises (x 2 = 7.9, p = 0.005) or use electrophysical modalities (x 2 = 4.3, p = 0.039). Physical therapists commonly examine and provide interventions directed at the hip(s) for individuals with LBP. Post-professional fellowship training appears to influence the intervention selection of the physical therapist, with an increase in usage of hip joint manual therapy and a decrease in hip muscle flexibility and modality usage. [ABSTRACT FROM AUTHOR]

Dynamic knee valgus (DKV) is an abnormal movement pattern visually characterized by excessive medial movement of the lower extremity during weight bearing. Differences in hip and knee kinematic components of DKV may explain the emergence of different pain problems in people who exhibit the same observed movement impairment. Using a secondary analysis of exiting data sets, we sought to determine whether hip and knee frontal and transverse plane angles during a functional task differed between women with patellofemoral pain and women with chronic hip joint pain and the relationship between joint-specific kinematics and pain in these 2 pain populations. In the original studies, 3-dimensional hip and knee kinematics during a single-limb squat were obtained in 20 women with patellofemoral pain and 14 women with chronic hip joint pain who demonstrated visually classified DKV. Pain intensity during the squat was assessed in both groups. For the secondary analysis, kinematic data were compared between pain groups using their respective control groups as a reference. Within each pain group, correlation coefficients were used to determine the relationship between kinematics and pain during the squat. Hip adduction and contralateral pelvic drop were greater in those with chronic hip joint pain compared to those with patellofemoral pain (effect sizes ≥0.40). Greater knee external rotation (r = 0.47, p = 0.04) was correlated with greater knee pain in those with patellofemoral pain, while greater hip adduction (r = 0.53, p = 0.05) and greater hip internal rotation (r = 0.55, p = 0.04) were correlated with greater hip pain in those with chronic hip joint pain. Hip frontal plane motion was greater in those with chronic hip joint pain compared to those with patellofemoral pain. In both groups, greater abnormal movement at the respective joint (e.g., knee external rotation in the patellofemoral pain group and hip adduction and internal rotation in the chronic hip joint pain group) was associated with greater pain at that joint during a single-limb squat. [ABSTRACT FROM AUTHOR]

Walking difficulties are common among pregnant women with pelvic girdle pain. This cross-sectional study investigated the influence of pelvic girdle pain, pregnancy and speed on spatiotemporal and trunk, pelvic and hip kinematics during gait in the 2nd trimester of pregnancy. Three-dimensional gait analysis at self-selected speed was performed in 25 pregnant women with pelvic girdle pain, 24 asymptomatic pregnant and 24 non-pregnant women. Linear mixed models were used to investigate between-group differences in gait variables. Adjustment for gait speed was included in the analysis. Correlations between speed and fear of movement, disability and pain were examined using Spearman correlation coefficient (r s). Pregnant women with pelvic girdle pain walked 18% slower (estimated marginal means (95% confidence intervals) 1.18 (1.22, 1.24) meter/s) compared to asymptomatic pregnant women (1.44 (1.38, 1.50) meter/s) (P < 0.001). Moreover, with longer double limb support (5%, P = 0.04), shorter contralateral step length (3%, P = 0.03) and more restricted pelvic and hip kinematics (0.001 ≤ P ≤ 0.01) adjusted for speed. Only stance, double limb support and thoracic rotation (0.001 ≤ P ≤ 0.04) differed between asymptomatic pregnant and non-pregnant women. Speed was negatively correlated with fear of movement (r s = −0.63, P = 0.01) and disability (r s = −0.46, P = 0.03) in the pelvic girdle pain group. Gait is primarily influenced by pelvic girdle pain and less by pregnancy. Pregnant women with pelvic girdle pain walked slower and with a more rigid gait pattern compared to asymptomatic pregnant women, presumably related to altered load transfer. Our results may assist clinical evaluation of pelvic girdle pain, as well as direct future research. • Walking is a main disability in pregnant women with pelvic girdle pain. • Pregnant women with pelvic girdle pain walked slow and rigid. • Gait pattern might be related to dysfunctional pelvic load transfer. • Gait was more influenced by pelvic girdle pain and less by pregnancy. • Mean gait speed was negatively correlated with fear of movement and disability. [ABSTRACT FROM AUTHOR]

The effect of pain on lower limb biomechanics during walking has been found to be sex specific for certain joint diseases. However, it is not known if sex is an effect-modifier in people with hip pain. Therefore, the aim of the study was to determine the differences in lower limb biomechanics between men and women with hip-related groin pain during functional tasks. 65 male and 23 female football players with hip-related groin pain were recruited. Biomechanical data were recorded during walking and the single-leg drop jump. Hip, knee and ankle joint kinematics and kinetics were calculated. Differences between men and women were assessed using statistical parametric mapping. Walking: Men with hip-related groin pain walked with lower hip flexion and internal rotation angles during stance compared to women. During different sections of stance, men also displayed a lower hip adduction angle and 'external' adduction moment, a lower knee flexion angle and 'external' flexion moment, as well as greater 'external' dorsi-flexion moment and impulse. Single-leg drop jump: Men with hip-related groin pain displayed a lower hip flexion angle during early stance, and greater 'external' knee flexion and ankle dorsi-flexion moments. The impulse of the 'external' dorsi-flexion moment was also greater for men compared to women. Men and women with hip-related groin pain display differing lower limb biomechanics in both low and high impact tasks. Sex may therefore be a potential effect modifier in people with hip-related groin pain. Future research in this area should incorporate sex-specific analyses. NA. • Men and women with hip-related groin pain have differing lower limb biomechanics. • Ankle joint biomechanics were consistently different between groups across tasks. • Sex may be an effect modifier in hip-related groin pain biomechanics. [ABSTRACT FROM AUTHOR]

Anterior cruciate ligament tears have a negative psychological impact on athletes. Currently, it is not clear if psychological readiness to return to sport has an impact on an athlete's landing biomechanics. Thus the purpose of the study is to investigate whether there is an association of psychological readiness to return to sport and single-leg landing biomechanics. Athletes with an anterior cruciate ligament reconstruction (n = 18) completed the Anterior Cruciate Ligament-Return to Sport after Injury scale to measure psychological readiness to return to sport, knee strength testing, and a single-leg landing task. A multivariate linear regression model was built for the involved and uninvolved limb based on sagittal and frontal plane knee and hip range of motion. Significance was set at p < 0.05. Knee extensor/flexor strength testing showed significant differences (p < 0.05) between involved and uninvolved limbs. Nearly 40% of the variance in psychological readiness scores (p = 0.025) can be accounted for by the involved limb's frontal plane hip and knee range of motion. Knee frontal plane range of motion was the only significant factor, and the standardized coefficients indicate that greater knee frontal plane range of motion and lower hip frontal plane range of motion were associated with higher psychological readiness. No other associations were found between psychological readiness and sagittal or frontal plane sing-leg biomechanics of the involved or uninvolved limbs. Greater psychological readiness to return to sport is associated with the involved limb's frontal plane knee and hip range of motion during a single-leg landing biomechanics. • Anterior cruciate ligament tears have a negative psychological impact on athletes. • Psychological readiness to return to sport is related with hip and knee kinematics. • Understanding the association of psychology and biomechanics will improve care. [ABSTRACT FROM AUTHOR]

Background: Achieving a neutral static Hip-Knee-Ankle angle (sHKA) measured on radiographs has been considered a factor of success for total knee arthroplasty (TKA). However, recent studies have shown that sHKA seems to have no effect on TKA survivorship. sHKA is not representative of the dynamic loading occurring during gait, unlike the dynamic HKA (dHKA).Research Question: The primary objective was to see if the sHKA is predictive of the dynamic HKA (dHKA). A secondary objective was to document to what degree the dHKA changes during gait.Methods: We analysed 3D knee kinematics during gait of a cohort of 90 healthy individuals with the KneeKG™ system. dHKA was calculated and compared with sHKA. Knees were considered "Stable" if the dHKA remained in valgus or varus for greater than 95% of the corresponding phase, and "Changer" otherwise. Patient characteristics of the Stable and Changer knees were compared to find associated factors.Results: Absolute variation of dHKA during gait was 10.9 ± 5.3° for the whole cohort. The variation was less for the varus knees (10.3 ± 4.8°), than for the valgus knees (12.8 ± 6.1°, p = 0.008). We found low to moderate correlations (r = 0.266 to 0.553, p < 0.001) between sHKA and dHKA values for varus knees and no significant correlation for valgus knees. Twenty two percent (36/165) of the knees were considered Changers. The proportion of knees that were Changers was 15% of the varus versus 39% of the valgus (p < 0.001).Significance: Lower limb radiographic measures of coronal alignment have limited value for predicting dynamic measures of alignment during gait. [ABSTRACT FROM AUTHOR]

Background: Age-related changes, which include increased trunk and hip stiffness, negatively influence postural balance. While previous studies suggest no net-effect of trunk and hip stiffness on initial trip-recovery responses, no study to date has examined potential effects during the dynamic restabilisation phase following foot contact.Research Question: Does increased trunk and hip stiffness, in isolation from other ageing effects, negatively influence balance during the restabilisation phase of reactive stepping.Methods: Balance perturbations were applied using a tether-release paradigm, which required participants to react with a single-forward step. Sixteen young adults completed two blocks of testing: a baseline and an increased stiffness (corset) condition. Whole-body kinematics were utilized to estimate spatial step parameters, center of mass (COM), COM incongruity (peak - final position) and time to restabilisation, in anteroposterior (AP) and mediolateral (ML) directions.Results: In the corset condition, peak COM displacement was increased in both directions (p < 0.024), which drove reductions in minimum margins of stability (p < 0.032) as step width and length were unchanged (p > 0.233). Increased passive stiffness also increased the magnitude and variability of peak shear ground reaction force, COM incongruity, and time to restabilisation in the ML (but not AP) direction (p < 0.027).Significance: In contrast to previous literature, increased stiffness resulted in greater peak COM displacement in both directions. Our results suggest increased trunk and hip stiffness have detrimental effects on dynamic stability following a reactive step, particularly in the ML direction. Observed increases in magnitude and variability of COM incongruity suggest the likelihood of a sufficiently large loss of ML stability - requiring additional steps - was increased by stiffening of the hips and trunk. The current findings suggest interventions aiming to mobilize the trunk and hips, in conjunction with strengthening, could improve balance and reduce the risk of falls. [ABSTRACT FROM AUTHOR]

The stand-to-sit motion has been linked to falls during pregnancy. It is also used in the clinical evaluation of functional performance. The physical and physiological changes during pregnancy may necessitate a change in stand-to-sit kinematic performance. Therefore, this study was conducted to evaluate the longitudinal changes to stand-to-sit kinematics during pregnancy. Fifteen pregnant women were tested in 4-week intervals from 16 weeks to 36 weeks gestational age. They performed a 60-second trial of semi-continuous stand-to-sit motion. Sagittal plane motions at the ankle, knee, spine, and shoulders were measured. Additionally, three-dimensional hip motion was measured. Discrete variables (e.g. range of motion) and joint coordinations (through vector coding) were analyzed over time through a linear mixed model analysis. The results indicate a shift away from sagittal hip motion throughout pregnancy. Hip range of motion and standing angle changed in favor of spine motion. Joint coordination shifted from hip dominant to spine- and shoulder-dominate coordination just before the start of sitting motion. Hip-knee joint coordination just before seat contact shifted from hip to a knee-dominant motion during pregnancy. Discrete variable changes in the entire stand-to-sit motion seem to be driven by initial standing posture related to an increase in gestational lordosis. Likewise, standing joint coordination shift to upper body motion can be attributed to gestational lordosis limiting functional ability around the hip. The shift in motion away from the hip may provide insight into why both fall rates and low back pain rates increase during stand-to-sit during pregnancy. • Hip and spine motion change for pregnant women performing a sitting task. • Postural changes related to gestational lordosis affect stand-to-sit changes. • Coordination changes away from the hip during the first and last parts of sitting. [ABSTRACT FROM AUTHOR]

Background: Anterior pericapsular muscles potentially contribute to active hip joint stability in walking by controlling anterior femoral translation in peak extension. Alternatively, these muscles could flex the hip and tension the anterior capsule to aid initiation of swing. Although never investigated, the location of Iliocapsularis and its extensive anterior hip capsule attachment imply a potential role in these functions. We hypothesised if these muscles contribute to control of femoral head translation (rather than hip flexion), their activation would decrease when peak hip extension is reduced during shorter stride walking.Research Questions: To provide the first description of iliocapsularis activity during walking and challenge the hypothesised roles of the anterior pericapsular hip muscles in gait by walking with shortened strides.Methods: Fifteen healthy volunteers walked with self-selected and shortened stride lengths. Electromyographic recordings were made from iliocapsularis, iliacus and anterior gluteus minimus with intramuscular electrodes, and rectus femoris with surface electrodes. Stride characteristics were measured using force sensors and 3D motion capture. Ensembles of burst activity profiles for each stride length were compared.Results: Iliocapsularis displayed a consistent EMG burst around toe-off (terminal hip extension) that peaked during early swing phase with self-selected strides. In shortened strides, iliocapsularis EMG increased during mid to late stance (p = 0.03), with no difference in other muscles. Iliocapsularis, iliacus and rectus femoris activity decreased during early stance (p < 0.01) in short strides, whereas gluteus minimus EMG increased (p = 0.03).Significance: Iliocapsularis displayed an EMG burst around toe-off during walking, and greater EMG during mid-late stance in short stride walking, which was not seen in other pericapsular muscles. Shortened strides increase the demand for active tensioning of the hip joint capsule in initial swing, and suggests a role for iliocapsularis during active hip flexion in pain free young individuals. [ABSTRACT FROM AUTHOR]

Background: The pelvis is commonly tracked during three-dimensional motion analysis using markers located on the anterior and posterior superior iliac spines. However, these markers are prone to soft tissue artefact and marker occlusion, highlighting the need for alternative technical marker sets.Research Question: How comparable are hip joint kinematics calculated using two alternative pelvic technical marker sets and a conventionally modelled pelvis?Methods: Fourteen participants undertook 3D gait analysis, walking overground at a self-selected pace (1.38 ± 0.14 m·s-1), barefoot. Hip joint kinematics were compared using root mean square error (RMSE) between a conventionally tracked pelvis and two alternative technical marker sets; (1) posterior cluster and (2) additional iliac crest markers.Results: The average RMSE in the sagittal, frontal and transverse planes was 2.5° ± 2.8°, 1.6° ± 0.4° and 0.8° ± 0.4°, respectively for the posterior cluster, and 1.3° ± 0.7°, 0.8° ± 0.3° and 1.4° ± 0.5° for the iliac crest marker set. The RMSE was significantly larger for the posterior cluster compared to the iliac crest model in the sagittal (p =  .05, d = .28) and frontal planes (p <  .001, d = 7.65). In contrast, the RMSE was significantly lower for the posterior cluster in the transverse plane (p =  .01, d = -2.85).Significance: The findings of this study suggest that either a posterior cluster or additional iliac crest markers offer means of accurately calculating hip joint kinematics within 3° of the conventional pelvic model. Therefore, either technical marker set offers a viable alternative to the conventional pelvic model for calculating hip joint kinematics. [ABSTRACT FROM AUTHOR]

Background: In treating patients with limitations of hip motion, it is generally assumed that correction of bony morphology will provide the patient with the joint motion required to resume their activities. However, the positions of impingement and the specific excursions of joint motion required by each sport may vary. This systematic review aimed to define the envelope of active hip joint motion for participation in different sporting, recreational, and daily-living activities.Methods: The EMBASE, PubMed, Google Scholar, and Cochrane databases were searched to identify studies that reported kinematics of the hip in sporting, recreational, and daily-living activities. Inclusion criteria were (1) peer-reviewed articles reporting hip kinematics in a certain type of activity, and (2) presented in English. To synthesize the kinematic data, the peak values of kinematic components (i.e. flexion/extension, abduction/adduction, and internal/external rotation) during an activity, as well as the concurrent values in a certain phase of the activity were collected from each study.Results: A total of 67 studies met the inclusion criteria, involving 32 different types of activities. Seventeen activities required at least one component of supra-physiologic hip motion, however, there were eight different combinations of flexion/extension, abduction/adduction, and internal/external rotation observed. Specifically, three activities (sex, sitting cross-legged, and grand ecart lateral of ballet dancing) required simultaneous extreme degrees of all three components, five activities (arabesque, developpe devant right, and developpe a la seconde right of ballet dancing, picking up something, and taekwondo) required high degrees of two components, most commonly hip abduction combined with flexion or internal rotation.Significance: This review highlighted that many activities place supraphysiologic demands on hip joint motion, however, the kinematic components affected differ dramatically with the specific activity. This suggests that the demands of each patient's individual activities must be assessed before recommending or planning treatment rather than assuming that a fixed value of "normal" hip motion is applicable to all. [ABSTRACT FROM AUTHOR]

Background: Overground locomotion exhibits greater movement variability and less dynamic stability compared to typical fixed-speed treadmill walking. To minimize the differences between treadmill and overground locomotion, researchers are developing user-driven treadmill systems that adjust the speed of the treadmill belts in real-time based on how fast the subject is trying to walk.Research Question: Does dynamic structure of variability, quantified by the Lyapunov exponent (LyE), of joint angles and center of mass (COM) position differ between a fixed-speed treadmill (FTM) and user-driven treadmill (UTM) for healthy subjects?Methods: Eleven healthy, adult subjects walked on a user-driven treadmill that updated its speed in real-time based on the subjects' propulsive forces, location, step length, and step time, and at a matched speed on a typical, fixed-speed treadmill for 1-minute. The LyE for flexion/extension joint angles and center of mass position were calculated.Results: Subjects exhibited higher LyE values of joint angles on the UTM compared to the FTM indicating that walking on the UTM may be more similar to overground locomotion. No change in COM LyE was observed between treadmill conditions indicating that subjects' balance was not significantly altered by this new training paradigm.Significance: The user-driven treadmill may be a more valuable rehabilitation tool for improving gait than fixed-speed treadmill training, as it may increase the effectiveness of transitioning learned behaviors to overground compared to fixed-speed treadmills. [ABSTRACT FROM AUTHOR]