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Context: Patellofemoral pain (PFP) is often categorized by researchers and clinicians using subjective self-reported PFP characteristics; however, this practice might mask important differences in movement biomechanics between PFP patients. Objective: To determine whether biomechanical differences exist during a high-demand multiplanar movement task for PFP patients with similar self-reported PFP characteristics but different quadriceps activation levels. Design: Cross-sectional design. Setting: Biomechanics laboratory. Participants: A total of 15 quadriceps deficient and 15 quadriceps functional (QF) PFP patients with similar self-reported PFP characteristics. Intervention: In total, 5 trials of a high-demand multiplanar land, cut, and jump movement task were performed. Main Outcome Measures: Biomechanics were compared at each percentile of the ground contact phase of the movement task (α =.05) between the quadriceps deficient and QF groups. Biomechanical variables included (1) whole-body center of mass, trunk, hip, knee, and ankle kinematics; (2) hip, knee, and ankle kinetics; and (3) ground reaction forces. Results: The QF patients exhibited increased ground reaction force, joint torque, and movement, relative to the quadriceps deficient patients. The QF patients exhibited: (1) up to 90, 60, and 35 N more vertical, posterior, and medial ground reaction force at various times of the ground contact phase; (2) up to 4° more knee flexion during ground contact and up to 4° more plantarflexion and hip extension during the latter parts of ground contact; and (3) up to 26, 21, and 48 N·m more plantarflexion, knee extension, and hip extension torque, respectively, at various times of ground contact. Conclusions: PFP patients with similar self-reported PFP characteristics exhibit different movement biomechanics, and these differences depend upon quadriceps activation levels. These differences are important because movement biomechanics affect injury risk and athletic performance. In addition, these biomechanical differences indicate that different therapeutic interventions may be needed for PFP patients with similar self-reported PFP characteristics. [ABSTRACT FROM AUTHOR]

This study investigated (a) site- and direction-dependent variations of passive triceps surae aponeurosis stiffness and (b) the relationships between aponeurosis stiffness and muscle strength and walking performance in older individuals. Seventy-nine healthy older adults participated in this study. Shear wave velocities of the triceps surae aponeuroses at different sites and in two orthogonal directions were obtained in a prone position at rest using supersonic shear imaging. The maximal voluntary isometric contraction torque of the plantar flexors and normal (preferred) and fast (fastest possible) walking speeds (5-m distance) were also measured. The shear wave velocities of the adjoining aponeuroses were weakly associated with plantar flexion torque (r =.23–.34), normal (r =.26), and fast walking speed (r =.25). The results show clear spatial variations and anisotropy of the triceps surae aponeuroses stiffness in vivo, and the aponeurosis stiffness was associated with physical ability in older adults. [ABSTRACT FROM AUTHOR]

Measuring ankle torque is of paramount importance. This study compared the test–retest reliability of the plantar flexion torque–generating capacity between older and younger men. Twenty-one older (68 ± 6 years) and 22 younger (25 ± 5 years) men were tested twice for maximal isometric plantar flexion. Peak torque (PT), rate of torque development, and contractile impulses (CI) were obtained from 0 to 50 ms (rate of torque development0–50; CI0–50) and from 100 to 200 ms (rate of torque development100–200; CI100–200). Typical error as the coefficient of variation (CVTE) and intraclass correlation coefficient were used to assess test–retest reliability. Student's t test was applied to investigate systematic errors. The CVTE ratio was used for between-group comparisons. Only PT demonstrated acceptable reliability (intraclass correlation coefficient ≥.75 and CV ≤ 10%). Older men demonstrated greater CVTE than younger men for PT (ratio = 2.24), but lesser for rapid torque (ratio ≤ 0.84). Younger men demonstrated systematic error for PT (6.5%) and CI100–200 (−8.9%). In conclusion, older men demonstrated greater variability for maximal torque output, but lesser for rapid torque. [ABSTRACT FROM AUTHOR]

Muscle force production is influenced by muscle fiber and aponeurosis architecture. This prospective cohort study utilizes special MR imaging sequences to examine the structure–function in-vivo in the Medial Gastrocnemius (MG) at three-ankle angles (dorsiflexion, plantar flexion—low and high) and two sub-maximal levels of maximum voluntary contraction (25% and 50%MVC). The study was performed on 6 young male participants. Muscle fiber and aponeurosis strain, fiber strain normalized to force, fiber length and pennation angle (at rest and peak contraction) were analyzed for statistical differences between ankle positions and %MVC. A two-way repeated measures ANOVA and post hoc Bonferroni-adjusted tests were conducted for normal data. A related samples test with Friedman's 2-way ANOVA by ranks with corrections for multiple comparisons was conducted for non-normal data. The dorsiflexed ankle position generated significantly higher force with lower fiber strain than the plantarflexed positions. Sarcomere length extracted from muscle fiber length at each ankle angle was used to track the location on the Force–Length curve and showed the MG operates on the curve's ascending limb. Muscle force changes predicted from the F-L curve going from dorsi- to plantarflexion was less than that experimentally observed suggesting other determinants of force changes with ankle position. [ABSTRACT FROM AUTHOR]

Background: Supramalleolar osteotomy (SMOT) has emerged as a valuable treatment for ankle varus deformity; however, there are fewer reports of treatment outcomes in adolescents. The purpose of this study was to investigate the radiologic and clinical outcomes of SMOT for the treatment of traumatic ankle joint varus deformity (TAVD) in adolescents. Methods: We reviewed 32 adolescent cases who underwent SMOT between February 2017 and February 2022 for TAVD. Radiologic assessment included tibial anterior surface angle (TAS), talar tilt angle (TT), and tibial lateral surface angle (TLS) preoperatively and at 3 months and 12 months postoperatively, and clinical assessment was performed using American Orthopaedic Foot and Ankle Society (AOFAS) scores, Visual Analogue Scale (VAS) scores, and ankle dorsiflexion–plantarflexion ROM including preoperative and 6 months postoperative and 12 months postoperative. Results: All 32 patients were followed up completely with a mean follow-up of (20.3 ± 3.2) months. From the radiologic outcomes, the mean preoperative TAS improved from 61.53 ± 3.74 to 88 ± 1.72 at 12 months postoperatively, the mean preoperative TT decreased from 2.25 ± 1.32 to 0.5 ± 0.57 at 12 months postoperatively, the mean preoperative TLS improved from 76.72 ± 0.21 to 79.34 ± 1.52 at 12 months postoperatively, the differences between the above preoperative and 12 months postoperative radiologic outcomes were statistically significant (p < 0.05), the mean preoperative AOFAS score improved from 65.5 ± 9.40 to 92.34 ± 4.00 at 12 months postoperatively, the mean preoperative VAS score decreased from 2.44 ± 1.24 to 0.78 ± 0.75 at 12 months postoperatively, and the mean preoperative range of motion (ROM) of ankle improved from 50.16 ± 7.46 to 55.78 ± 4.77 at 12 months postoperatively. The differences between the above preoperative and 12 months postoperative clinical results were statistically significant (p < 0.05). Conclusion: Our study demonstrated that SMOT was effective in correcting TAVD and significantly improving ankle function in adolescents, and that it is an efficient and successful method for restoring ankle joint congruence and normal hindfoot alignment. [ABSTRACT FROM AUTHOR]

Purpose: Evaluating central and peripheral processes responsible for reduced power after dynamic fatiguing tasks are often limited to isometric torque, which may not accurately reflect dynamic contractile performance. Here, we compare voluntary and electrically evoked peak power (and its determinants: dynamic torque and velocity) and rate of velocity development (RVD) before and after a dynamic fatiguing task using concentric Plantar flexion contractions. Methods: Young (18-32 yr) males (n = 11) and females (n = 2) performed maximal-effort isotonic Plantar flexion contractions using a load of 20% isometric torque until an approximately 75% reduction in peak power. Voluntary and electrically evoked (300 Hz tibial nerve stimulation) contractions loaded to 20%and 40%isometric torque through 25° ankle joint range of motion were compared before and 0, 2.5, 5, and 10 min after task termination. Results: At task termination, peak power and RVD of voluntary contractions at both loads were reducedmore (~40%to 50%reduction) than electrically evoked (~25%to 35%reduction) contractions (P < 0.001 and P = 0.003). Throughout the recovery period, electrically evoked peak power and RVD returned to baseline sooner (<5 min) than voluntary contractions, which were still depressed at 10 min. Reductions in peak power for the 20% load were equally due to impaired dynamic torque and velocity, whereas velocity was impaired more than dynamic torque (P < 0.001) for the 40% load. Conclusions: The relative preservation of electrically evoked power and RVD compared with voluntary contractions at task termination and quicker recovery to baseline indicates that the reductions in dynamic contractile performance after task termination are due to both central and peripheral processes; however, the relative contribution of dynamic torque and velocity is load dependent. [ABSTRACT FROM AUTHOR]

Purpose: The amount of muscle belly elongation induced by passive lengthening is often assumed to be equal to that of fascicles. But these are different if fascicles shorter than themuscle belly rotate around their attachment sites. Such discrepancy between fascicles andmuscle belly length changes can be considered as gearing. As the muscle fascicle arrangement is 3D, the fascicle rotation by passive lengthening may occur in the coronal as well as the sagittal planes. Here we examined the fascicle 3Ddynamics and resultant gearing during passive elongation of human medial gastrocnemius in vivo. Methods: For 16 healthy adults, we reconstructed fascicles three-dimensionally using diffusion tensor imaging and evaluated the change in fascicle length and angles in the sagittal and coronal planes during passive ankle dorsiflexion (from 20° plantar flexion to 20° dorsiflexion). Results: Wholemuscle belly elongation during passive ankle dorsiflexionwas 38% greater than the fascicle elongation. Upon passive lengthening, the fascicle angle in the sagittal plane in all regions (-5.9°) and that in the coronal plane in themiddle-medial (-2.7°) and distal-medial (-4.3°) regions decreased significantly. Combining the fascicle coronal and sagittal rotation significantly increased the gearing effects in the middle-medial (+10%) and distal-medial (+23%) regions. The gearing effect by fascicle sagittal and coronal rotations corresponded to 26%of fascicle elongation, accounting for 19% of wholemuscle belly elongation. Conclusions: Fascicle rotation in the coronal and sagittal planes is responsible for passive gearing, contributing to the wholemuscle belly elongation. Passive gearing can be favorable for reducing fascicle elongation for a given muscle belly elongation. [ABSTRACT FROM AUTHOR]

When studying ball kicking, conventional low-pass filters may distort kick leg kinematics near the time of foot-to-ball contact, leading to flawed practical interpretation of the skill. Time-frequency filters are a viable alternative but are not widely used. This study compared a fractional Fourier filter (FrFF) with conventional filters (CF) methods for estimating common parameters used to define kicking performance. Instep kicks from 23 experienced soccer players were captured by 3D motion analysis (1000 Hz), and kick leg foot velocities, knee angular velocities and ankle dorsi-plantarflexion angles compared between the FrFF and variations of a Butterworth CF. The FrFF and CFs using a higher cut-off frequency (>70 Hz) successfully detected lower leg motion prior to, during and following impact, whereas CFs with low cut-off frequencies (<20 Hz) attenuated motion near impact. Truncating data at impact provided valid pre-impact kinematics, but ignored information thereafter. Rather than decelerating the lower leg to conserve accuracy, 'kicking through the ball' should be considered a valid coaching cue. Further, controlling ankle plantar flexion to ensure efficient impact mechanics may be important for skilled kicking. Practitioners should consider how choice of filter will affect their data, and use of time-frequency methods can help inform empirically grounded coaching practices. [ABSTRACT FROM AUTHOR]

Torsion of the Achilles tendon (AT) enhances tensile strength, but a high degree of torsion might also be a risk factor for Achilles tendinopathy, due to greater internal compression exerted during tensile loading. However, evidence supporting the grounds for this assumption is lacking. Hence, we aimed to investigate the impact of AT torsion type on intratendinous pressure. Eighteen human fresh frozen cadaveric legs were mounted in a testing rig and a miniature pressure catheter was placed through ultrasound‐guided insertion in the midportion region of the AT. Intratendinous pressure was measured during a simulated straight‐knee calf stretch and eccentric heel drop. The AT was then carefully dissected and classified into Type I (least), Type II (moderate), and Type III (extreme) torsion. Of the ATs examined, nine were found to have Type I torsion (50%), nine Type II (50%), and none Type III. It was found that the intratendinous pressure of the AT increased exponentially with ankle dorsiflexion during both exercises (p < 0.001) and that this increase was greater in ATs with Type II torsion than Type I torsion (p < 0.05). This study provides the first biomechanical data to support the hypothesis that in athletes with a high degree of torsion in the AT, the midportion area will experience more internal compression during exercise, for example, calf stretching and eccentric heel drops. Whether this phenomenon is also associated with an elevated risk for Achilles tendinopathy needs further prospective investigation. [ABSTRACT FROM AUTHOR]

To examine the effect of ankle position (i.e. gastrocnemius muscle length) on training outcomes during leg curl exercise, we recruited untrained and trained healthy adults to participate in two separate experiments. In Experiment 1, we studied the acute influence of ankle position on knee flexor myoelectric (EMG) activity during leg curl exercise in a group of trained and a separate group of untrained adults. In Experiment 2, we studied the effects of ankle position on knee flexors muscle thickness and torque across a 10-week training protocol in trained adults. We hypothesized that leg curl exercise with the ankle in a plantarflexed position would enhance EMG activity, muscular strength, and hamstrings muscle thickness. We randomized the legs within a person to perform leg curl exercise with one in a plantarflexed position and the other in a dorsiflexed position. Experiment 1 revealed no significant differences between ankle positions in the EMG activity of hamstring muscle in either group (all p > 0.05). Experiment 2 revealed a significant pre- to post-intervention increase in biceps femoris long head (BFLH) muscle thickness (p = 0.026) and isometric torque (p = 0.03), but there were no significant effects of the ankle position (p = 0.596) or interaction between ankle position and timepoint for these variables (p = 0.420). In sum, the ankle position did not have acute effects on hamstrings EMG activity, nor did it affect strength and hypertrophy adaptations after 10-weeks of leg curl exercise training. Interestingly, however, the limb which performed leg curl exercise in a dorsiflexed position performed a higher total training volume. Highlights Different ankle positions (i.e. dorsiflexion or plantarflexion) do not affect hamstrings EMG activity during prone leg curl exercise. Different ankle positions show similar adaptation in strength and hypertrophy of biceps femoris long head after 10 weeks of training. Training in the plantarflexed position may be useful for time-constrained individuals, allowing similar training adaptations with smaller training volume. [ABSTRACT FROM AUTHOR]

Individuals with chronic ankle instability (CAI) exhibit altered movement strategies during side-cutting tasks. However, no researchers have assessed how altered movement strategies affect cutting performance. To investigate compensatory strategies in the side-hop test (SHT), with a focus on the entire lower extremity, among individuals with CAI. Cross-sectional study. Laboratory. A total of 40 male soccer players comprising a CAI group (n = 20; age = 20.35 ± 1.15 years, height = 173.95 ± 6.07 cm, mass = 68.09 ± 6.73 kg) and a control group (n = 20; age = 20.45 ± 1.50 years, height = 172.39 ± 4.39 cm, mass = 67.16 ± 4.87 kg). Participants performed 3 successful SHT trials. We calculated SHT time, torque, and torque power in the ankle, knee, and hip joints during the SHT using motion-capture cameras and force plates. Confidence intervals for each group that did not overlap by >3 points consecutively in the time series data indicated a difference between groups. Compared with the control group, the CAI group showed (1) no delayed SHT time; (2) lower ankle-inversion torque (range = 0.11–0.13 N·m/kg) and higher hip-extension (range = 0.18–0.72 N·m/kg) and -abduction torque (0.26 N·m/kg); (3) less concentric power in ankle dorsiflexion-plantar flexion (0.18 W/kg) and inversion-eversion (0.40 W/kg), more concentric power in hip flexion-extension (0.73 W/kg), and more eccentric power in knee varus-valgus (0.27 W/kg). Individuals with CAI were likely to rely on hip-joint function to compensate for ankle instability and demonstrated no differences in SHT time compared with the control group. Therefore, the movement strategies of individuals with CAI could differ from those of individuals without CAI, even if SHT time is not different. [ABSTRACT FROM AUTHOR]

This paper presents the design and testing of an arched foot with several biomimetic features, including five individual MTP (toe) joints, four individual midfoot joints, and plantar fascia. The creation of a triple-arched foot represents a step further in bio-inspired design compared to other published designs. The arched structure creates flexibility that is similar to human feet with a vertical deflection of up to 12 mm. The individual toe joints enable abduction–adduction in the forefoot and therefore a natural pronation motion. Adult female bone data was obtained and converted into a CAD model to accurately identify the location of bones, joints, and arches. An analytical model is presented that gives the relationship between the vertical stiffness and horizontal stiffness of the longitudinal arches and therefore allows the optimization of stiffness elements. Experimental tests have demonstrated a vertical arch stiffness of 76 N/mm which is similar to adult human feet. The range of movement of the foot is similar to human feet with the following values: dorsi-plantarflexion (28°/37°), inversion-eversion (30°/15°), and abduction–adduction (30°/39°). Tests have also demonstrated a three-point contact with the ground that is similar to human feet. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the characteristics of gait patterns in Charcot-Marie-Tooth disease type 1A (CMT1A) patients according to disease severity. Twenty-two CMT1A patients were enrolled and classified into two groups, according to the disease severity. The healthy control group consisted of 22 subjects with no gait impairment. Full barefoot three-dimensional gait analysis with temporospatial, kinematic, and kinetic data was performed among the mild and moderate CMT1A group and the control group. Minimal hip abduction, maximal hip extension generation, peak knee flexion moment at stance, ankle dorsiflexion at initial contact, maximal ankle plantarflexion at push-off and maximal ankle rotation moment at stance in the CMT1A group showed a significant difference compared to the control group (p < 0.05). In the moderate group, there were greater maximal hip flexion angles in swing, and smaller dorsiflexion angles at initial contact compared to the control group and mild group. CMT patients had typical gait characteristics and their gait patterns were different according to severity. The analysis of gait patterns in patients with CMT1A will help to understand gait function and provide important information for the treatment of patients with CMT in the future. [ABSTRACT FROM AUTHOR]

An accurate and reliable neurological examination is pivotal in diagnosing patients with neurological and neurosurgical conditions. Despite the advancement of neuroscientific knowledge and the ever-progressing technologies and modalities that are being adopted to help achieve the challenge of accurate diagnosis, the neurologic examination is still crucial in both ambulatory and emergency settings. It provides the physician a tool to recognise neurologic involvement in certain disease states, and thereby allow proper work-up and treatment for patients. A basic neurologic examination can be performed rapidly with practice. Manual muscle testing of the lower limbs was carried out in accordance with a bedside clinical examination involving a clinical personnel examiner and a patient. This testing was performed in a rostro-caudal manner, starting from the hip and progressing to the toes. The neurological exam can be intimidating to perform for a lot of physicians. Deficiencies in accurate muscle testing have always presented a challenge for medical students and clinicians. By referring to the examination methods mentioned in our text and with the help of related video, it is our aim to improve the quality of neurological examination among medical personnel so that diseases may be recognised and managed earlier in their course. [ABSTRACT FROM AUTHOR]

Flat foot is associated with increased odds of the lower extremity injury and pour posture balance [1]. Orthotic insole is one of the effective treatments to attribute the abnormally distributed pressure and help improve posture balance. The aim of the study is to design orthotic insoles for children with flatfoot based on their arch morphology to improve posture balance, followed by a preliminary validation on the practice effects. Eighty-nine normal weight children aged 8-12 years were recruited, and classified into the flatfoot group (n = 49, AI > 0.26) and the control group (n = 40, 0.21 < AI < 0.26). Foot morphology and plantar pressure of the participants were collected by an Infoot® 3D scanning system and a Footscan® plate measurement system. Orthotic insoles were designed based on the highest point in the anatomical structure of the foot arch of flatfoot group, combined with their typical plantar pressure. Total 9 insoles with three arch heights (2.0 cm, 2.5 cm, 3.0 cm) and three 3D printing infill densities (25%, 30%, 35%) were printed (Fig. 1b). Three infill densities were used to achieve different softness. The weight of each insole was less than 41 grams. To test the effect of restoring balance, 3 participants with flatfoot were recruited to walk in a natural speed with and without the orthotic insoles. The AI of them were 28.9%, 30.4%, and 32.0%, respectively. The center of pressure (COP) trajectory and gait phase were recorded by Footscan® plate measurement system. In the meantime, to quantify the effect of orthotic insoles, a comprehensive scoring scheme was established including the subjective evaluation and balancing effect. All of the orthotic insoles have improved the COP and gait phase of the participants, regarding the pattern of normal foot (Fig. 1c-d). The COP trajectory shifted laterally and the forefoot contact phase decreased when wearing the orthotic insoles. According to the comprehensive scores, the suitable orthotic insole for the three participants was group 8 insole, group 3 insole, and group 3 insole, respectively. Fig. 1 (a) The design of orthotic insole for children with flatfoot. (b) 3D printing orthotic insoles for children with flatfoot. (c) COP trajectories of all participants. (d) Gait phase of all participants. [Display omitted] The orthotic insoles designed in this study improved the posture balance of participants with flat foot. The optimal parameters of orthotics vary with the dgree of flatness, considering the arch height and hardness. [ABSTRACT FROM AUTHOR]

Plantar flexor weakness reduces ankle push-off work during walking, causing inefficient proximal joint compensations to provide power for forward propulsion (1). To support ankle push-off work and reduce compensations, spring-like ankle foot orthoses (AFOs) can be applied (2). In people with plantarflexor weakness due to a neuromuscular disease, spring-like AFOs can increase push-off work, which is often accompanied by increases in walking speed (3). The higher walking speed likely also leads to higher proximal joint work demands. Consequently, it is unknown whether the higher push-off work leads to a reduction in compensatory joint work. Furthermore, not all patients increase push-off work with the AFO and understanding of who is able to increase push-off work is warranted for clinical decision-making. 1) Do spring-like AFOs redistribute lower limb joint work during walking in people with bilateral plantar flexor weakness compared to shoes-only? 2) Is ankle work when walking without AFO related with the effect of spring-like AFOs on ankle and hip work? In 18 people with bilateral plantar flexor weakness, we performed a 3D gait analysis at self-selected walking speed for walking without and with a spring-like AFO with individually tuned stiffness. We compared the relative joint work generated at the hip, knee and ankle between conditions. Furthermore, the association between ankle work without orthosis and joint work using the AFO were tested with Pearson's correlations. No difference in the relative contribution of ankle, knee and hip work to total joint work over the gait cycle was found between walking with and without AFO (p >0.499). Relative ankle work generated during pre-swing increased with the AFO (Shoes: 72.4±27.1% vs AFO: 85.3±9.1% of total ankle work, p =0.026). At the hip, relative less work was generated in pre-swing (Shoes: 34.1±10.4% vs AFO: 31.9±7.4% of total hip work, p =0.038) and more in loading response (Shoes: 11.9±9.8% vs AFO: 18.0±11.0%, p =0.022). Ankle work without AFO was inversely correlated with increased ankle work with the AFO (r=0.839, p <0.001) and this increase correlated with a larger reduction in hip work (r=-0.650, p =0.004). Although spring-like AFOs increased relative ankle work and reduced hip work during push-off, the relative hip and knee work did not reduce as hip extensor work in early stance increased. However, a higher ankle push-off deficit without AFO was related with more AFO support and higher reductions in compensatory hip work, which indicates that people with more severe push-off deficits benefit more from the energy storing-and-releasing capacity of spring-like AFOs. [ABSTRACT FROM AUTHOR]

Normal ankle function provides a key contribution to everyday activities, particularly step/stair ascent and descent, where many falls occur. The rising to up-on-the-toes (UTT) 30 second test (UTT-30) is used in the clinical assessment of ankle muscle strength/function and endurance and is typically assessed by an observer counting the UTT movement completed. The aims of this study are: (i) to determine whether inertial measurement units (IMUs) provide valid assessment of the UTT-30 by comparing IMU-derived metrics with those from a force-platform (FP), and (ii) to describe how IMUs can be used to provide valid assessment of the movement dynamics/stability when performing a single UTT movement that is held for 5 s (UTT-stand). Twenty adults (26.2 ± 7.7 years) performed a UTT-30 and a UTT-stand on a force-platform with IMUs attached to each foot and the lumbar spine. We evaluate the agreement/association between IMU measures and measures determined from the FP. For UTT-30, IMU analysis of peaks in plantarflexion velocity and in FP's centre of pressure (CoP) velocity was used to identify each repeated UTT movement and provided an objective means to discount any UTT movements that were not completed 'fully'. UTT movements that were deemed to have not been completed 'fully' were those that yielded peak plantarflexion and CoP velocity values during the period of rising to up-on-the-toes that were below 1 SD of each participant's mean peak rising velocity across their repeated UTT. The number of UTT movements detected by the IMU approach (23.5) agreed with the number determined by the FP (23.6), and each approach determined the same number of 'fully' completed movements (IMU, 19.9; FP, 19.7). For UTT-stand, IMU-derived movement dynamics/postural stability were moderately-to-strongly correlated with measures derived from the FP. Our findings highlight that the use of IMUs can provide valid assessment of UTT test(s). [ABSTRACT FROM AUTHOR]

Purpose: To identify the effects of fatigue from an exercise protocol (similar to a soccer match) on ankle motion and forces during single-legged drop landing. Methods: Seventeen males aged (mean ± SD) 22.2 ± 2.0 years participated in this repeated measures study. A 90-min intermittent exercise protocol with a 15-min rest at halftime was performed. Before, at halftime and after the exercise, participants were tested via a single-legged drop landing task onto a force platform whilst wearing a three-dimensional inertial measurement system (Xsens). Ankle angles (plantarflexion/dorsiflexion and inversion/eversion) were analysed before landing and at peak ground reaction force after landing, and center of pressure was analysed at peak ground reaction force. Results: No significant differences were found for the outcomes between pre-, halftime and post-exercise (p > 0.05). Conclusions: Findings suggest that exercises simulating a soccer match (regarding exertion) do not necessarily lead to significant changes in ankle motion or forces around the ankle. [ABSTRACT FROM AUTHOR]

Footstrike pattern has received increased attention within the running community because there is a common belief that forefoot strike running (FFS) is more advantageous (i.e., improve performance and reduce running injuries) than rearfoot strike running (RFS) in distance running. Literature reports suggest greater knee joint flexion magnitude and initial knee angle during stance in FFS compared with RFS running We examined the EMG activation of the triceps surae muscles during an acute transition from RFS to FFS strike. We tested the hypothesis that due to larger knee flexion in FFS the gastrocnemius muscles possibly decrease their EMG activity because muscle fascicles operate under unfavorable conditions. Fourteen competitive healthy middle- and long-distance runners who were habitual RFS runners ran on a treadmill at three speeds: 12, 14, and 16 km.h-1. Each running speed was performed with both FFS and RFS patterns. Lower limb kinematics in the sagittal plane and normalized electromyography (EMG) activity of medial gastrocnemius proximal, middle and distal regions, lateral gastrocnemius and soleus muscles were compared between footstrike patterns and running speeds across the stride cycle. Contrary to our expectations, the knee joint range of motion was similar in FFS and RFS running. However, the sagittal plane ankle joint motion was greater (p < 0.01) while running with FFS, resulting in a significantly greater muscle- tendon unit lengthening (p < 0.01) in FFS compared with RFS running. In addition, medial and lateral gastrocnemius showed higher EMG activity in FFS compared with RFS running in the late swing and early stance but only for a small percentage of the stride cycle. However, strike patterns and running speed failed to induce region-specific activation differences within the medial gastrocnemius muscle. Overall, well-trained RFS runners are able to change to FFS running by altering only the ankle joint kinematics without remarkably changing the EMG activity pattern. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to investigate the association between ankle torque and performance-based tests, self-reported pain, and physical function in patients with knee osteoarthritis (OA). Patients and methods: The cross-sectional study was conducted with 39 individuals (24 females, 15 males; mean age: 57.3±6.2 years; range, 40 to 65 years) with knee OA between January 2014 and July 2015. Ankle torque was determined using an isokinetic dynamometer. The 40-m fast-paced walk test and a stair climb test were used to assess functional performance. Self-reported pain and physical function were assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Pearson's correlation coefficients were calculated to test correlations between the dependent variables (40-m fast-paced walk test, stair climb test, WOMAC pain and physical function domains, sex, age, body mass index, and radiologic evidence of OA) and the independent variables (mean plantar flexor torque and dorsiflexor peak torque). A multiple linear regression analysis was applied to quantify the association between the dependent and independent variables. Results: Dorsiflexor and plantar flexor peak torques in the concentric and eccentric modes were negatively correlated with the 40-m fast-paced walk and stair climb tests (r=-0.33 to -0.51, p=0.05). A negative correlation was found between concentric plantar flexor torque and the WOMAC physical function score (r=-0.35, p=0.03). No correlation was found between ankle torques and the WOMAC pain score (p>0.05). The multiple linear regression analysis showed that the eccentric plantar flexor and dorsiflexor torques were significantly associated with the stair climb test (β=-0.001, 95% confidence interval [CI]: -0.001 to 0.000, p=0.03, and β=-0.002, 95% CI: -0.004 to 0.000, p=0.05, respectively). No significant associations were found between concentric plantar flexor and dorsiflexor torques and the stair climb test (p>0.05). No significant associations were found between the ankle torques and the 40-m fast-paced walk test and WOMAC physical function (p>0.05). Conclusion: Ankle torque plays an important role in functional performance. Thus, ankle torque deficit, especially eccentric plantar flexor and dorsiflexor torques, may exert a negative influence on stair climbing performance in patients with knee osteoarthritis. [ABSTRACT FROM AUTHOR]

BACKGROUND: Foam roller with vibration is a recent development and its implementation has not yet been provided with a sufficient scientific justification. Information on whether an implementation of vibration foam rolling for self-massage before the powerful muscular activities is a good strategy is scarce. OBJECTIVE: Therefore, the aim of this study was to determine the acute effects of a single 15-s and 60-s vibrating foam rolling treatment on muscle contractile properties during maximal voluntary isometric contraction (MVIC). METHODS: Twenty healthy and recreationally active subjects participated in this study. During first visit, baseline characteristics were collected, while on the second and third visit they performed a 15-s and a 60-s vibration foam rolling treatment, respectively. Their maximal force (F) max and rate of force development (RFD max) were assessed using the MVIC of plantarflexors. RESULTS: The RFD max was negatively affected (p ⩽ 0.05) after the 15-s treatment and 60-s treatment, staying reduced even after 10-min of recovery. No significant effects were observed for F max. CONCLUSIONS: When implementing vibration foam rolling, either as a pre-workout activity or as a pre-competition treatment, caution should be taken. Short duration treatment should be avoided for activities were RFD max has a significant impact on performance. [ABSTRACT FROM AUTHOR]

The purpose of the study was to investigate the foot posture, ankle muscle strength, range of motion (ROM), and plantar sensation differences among normal weight, overweight, and obese individuals. One hundred and twenty-three individuals (42 normal weight, 40 overweight, and 41 obese) aged between 18 and 50 years participated in the study. Foot posture, ankle muscle strength, ROM, plantar sensation, and foot-related disabilities were evaluated. The relative muscle strength of left plantar flexors and invertors and light touch sensation of the left heel were significantly lower in obese individuals compared with overweight and normal weight (P <.016) individuals. Obese individuals had significantly reduced relative muscle strength of plantar flexors, dorsiflexor, and invertors, plantar flexion and inversion ROM in the left foot; and light touch sensation of the right heel compared with normal weight (P <.016) individuals. Foot Posture Index scores were significantly higher in obese individuals compared with overweight (P <.016) individuals. There were no significant differences in absolute muscle strength, vibration sensation, and foot-related disability scores among the 3 groups (P >.05). Obesity was found to have adverse effects on ankle muscle strength, ROM, and plantar light touch sensation. Vibration sensation was not affected by body mass index, and foot-related disability was not observed in obese adults. [ABSTRACT FROM AUTHOR]

Context: Recently, a few papers have suggested that tissue flossing (TF) acutely improves range of motion (ROM) and neuromuscular performance. However, the effects of TF on muscle contractile properties are yet to be defined. Objective: To investigate the acute effects of TF on ankle ROM and associated muscle gastrocnemius medialis displacement and contraction time assessed with tensiomyography. Design: Crossover design in a single session. Setting: University laboratory. Participants: Thirty recreationally trained volunteers (age 23.00 [4.51] y). Intervention: Active ankle plantar flexion and dorsiflexion were performed for the duration of 2 minutes (3 sets, 2-min rest between sets), while a randomly selected ankle was wrapped using TF elastic band (BAND) and the other ankle served as a control condition (CON). Main outcome measures: Participants performed an active ankle plantar flexion and dorsiflexion ROM test and muscle gastrocnemius medialis tensiomyography displacement and contraction time measurement pre, 5, 15, 30, and 45 minutes after the floss band application. Results: There were no statistically significant differences between BAND and CON conditions (active ankle plantar flexion ROM: P = .09; active ankle dorsiflexion ROM: P = .85); however, all ROM measurements were associated with medium or large effect sizes in favor of BAND compared with CON. No significant changes were observed in the tensiomyography parameters. Conclusions: The results of this study suggest that TF applied to the ankle is a valid method to increase ROM and at the same time maintaining muscular stiffness. [ABSTRACT FROM AUTHOR]

Objective The purpose of the present study was to investigate the effects of two functional and functional stretching methods of the leg muscles on a selection of kinematic and kinetic indicators in women with ankle instability. Methods 24 people were selected and randomly divided into the functional exercise (8 persons), extra-functional exercise (8 persons) and control (8 persons) on the basis of inclusion and exclusion criteria. The experimental group underwent stretching exercises for eight weeks, 3 sessions each week, and the control group was merely performing its daily activities. Then, in order to measure the pre -test and post -test variables, the dorsiflexion, Plantar flexion and ground reaction force were investigated and measured. Data was analyzed using paired-samples T test and independent-samples T -tests at a significant level of 0.05 All statistical reviews were conducted using SPSS software version 25. Results The results of the T -test showed the significant effect of eight weeks of functional and Extra functional exercises on dorsiflexion, Plantar Flexion and ground reaction force. (P≤ 0/001). Conclusion The results of this study showed that the implementation of the functional and Extra-functional exercise protocol has an impact on the amount of Ankle dorsiflexion and the Plantar flexion of the Girls with an ankle instability. It was also found that muscle flexibility following the stretch ability of the gastrocnemius muscles by affecting the amount of wrist flexion facilitates the walking of the wrist installation, so these people are recommended to use the functional and Extra-functional exercise protocol.

Context: Several studies have reported that self-massage using a foam roller (FR) increased joint range of motion (ROM) immediately. However, the mechanism of increasing ROM by the FR intervention has not been elucidated. Objective: To clarify the mechanism by investigating properties and morphological changes of muscles targeted by the FR intervention. Design: An interventional study. Setting: An athletic training laboratory. Participants: Ten male college volunteers with no injuries in their lower limbs (mean [SD]: age 23.8 [3.2] y, height 173.2 [4.9] cm, weight 69.5 [8.6] kg). Intervention: The FR intervention on the right plantar flexors for 3 minutes. Main Outcome Measures: Maximum ankle ROM, muscle hardness, and fascicle length of the gastrocnemius muscle at the neutral (0°), maximum dorsiflexion, and maximum plantar flexion positions. All measurements were conducted before (PRE) and after (POST) the FR intervention. Results: Dorsiflexion ROM increased significantly at POST (PRE: 13.6° [8.0°], POST: 16.6° [8.4°]; P <.001), although plantar flexion ROM did not change significantly between PRE and POST (PRE: 40.0° [6.1°], POST: 41.1° [4.9°]). There was no significant difference in muscle hardness and fascicle length between PRE and POST in any of the angles. Conclusions: Dorsiflexion ROM increased significantly by the FR intervention in the present study; however, muscle hardness and fascicle length did not change. FR may affect not only the muscle but also the fascia, tendon, and muscle-tendon unit. The FR protocol of the present study can be applied in clinical situations, because it was found to be effective to increase ROM. [ABSTRACT FROM AUTHOR]

The purpose of the study was to investigate the effects of ankle angular position and standing surface type on static upright balance. Ten young adults stood on a force platform or on a firm wedge that induced 15° of either dorsiflexion or plantarflexion. In addition, a piece of foam was placed on top of the force platform and on the wedge. The center of pressure distance and velocity in the anteroposterior and mediolateral directions were calculated. Significantly larger magnitudes in most of the investigated variables were seen while standing with ankles in the dorsiflexion when compared with standing with the ankle joints in a natural position (p < .05). Plantarflexion increased the center of pressure anteroposterior velocity by 87% when compared with a natural stance (p < .05). Standing on the foam surfaces resulted in increases in all of the center of pressure measures by an average of 38% in all of the ankle conditions. [ABSTRACT FROM AUTHOR]

Clinical Scenario: Approximately 30% of all first-time patients with LAS develop chronic ankle instability (CAI). CAI-associated impairments are thought to contribute to aberrant gait biomechanics, which increase the risk of subsequent ankle sprains and the development of posttraumatic osteoarthritis. Alternative modalities should be considered to improve gait biomechanics as impairment-based rehabilitation does not impact gait. Taping and bracing have been shown to reduce the risk of recurrent ankle sprains; however, their effects on CAI-associated gait biomechanics remain unknown. Clinical Question: Do ankle taping and bracing modify gait biomechanics in those with CAI? Summary of Key Findings: Three case-control studies assessed taping and bracing applications including kinesiotape, athletic tape, a flexible brace, and a semirigid brace. Kinesiotape decreased excessive inversion in early stance, whereas athletic taping decreased excessive inversion and plantar flexion in the swing phase and limited tibial external rotation in terminal stance. The flexible and semirigid brace increased dorsiflexion range of motion, and the semirigid brace limited plantar flexion range of motion at toe-off. Clinical Bottom Line: Taping and bracing acutely alter gait biomechanics in those with CAI. Strength of Recommendation: There is limited quality evidence (grade B) that taping and bracing can immediately alter gait biomechanics in patients with CAI. [ABSTRACT FROM AUTHOR]

Context: Given the relatively novel technique of tissue flossing is currently lacking in the research literature despite some positive findings in preliminary studies, themodality clearly requires further research. Current evidence suggests that band flossing results in performance improvements and may also be an effective method in injury prevention. Objective: Previous research has shown that tissue flossing may result in increased ankle range of motion, jump, and sprinting performance in recreational athletes. The present study aims to extend on this research, within an elite athlete sample. Design: Counterbalanced, cross-over design with experimental and control trials, separated by 1 week. Setting: University laboratory. Participants: Fourteen professional male rugby union athletes (mean [SD]: age 23.9 [2.7] y). Intervention: Application of a floss band to both ankles (FLOSS) for 2 minutes or without flossing of the ankle joints (CON) on 2 separate occasions. Main Outcome Measures: A weight-bearing lunge test, a counter-movement jump test, and a 20-m sprint test at pre and at 5 and 30 minutes post application of the floss band or control. Results: There were no statistically significant interactions between treatment (FLOSS/CON) and time for any of the measured variables (P > .05). Effect size analysis revealed small benefits for FLOSS in comparison with CON for countermovement performance 5 minutes post (d = 0.28) and for 10-m (d = -0.45) and 15-m (d = -0.24) sprint time 30 minutes post. Conclusion: Findings from the current study suggest minimal benefits of tissue flossing when applied to the ankle joint in elite athletes for up to 30 minutes following their application. [ABSTRACT FROM AUTHOR]

Context: It is very important to empirically determine the optimal ankle position for the quadriceps femoris (QF) strengthening during isometric exercises. Objective: To examine the effect of different ankle positions on torque and electromyography (EMG) activity of QF during maximal isometric contraction. Study Design: Within-subject repeated measures. Setting: University laboratory. Participants: Thirty-six healthy volunteers (15 males and 21 females). Main Outcome Measures: The isometric strength of the QF was measured at 3 different ankle positions: active dorsiflexion (AD), active plantar flexion (AP), and neutral position (NP). Simultaneously, 3 different ankle positions were assessed for EMG activity of the vastus medialis, vastus lateralis, and rectus femoris muscles during maximal voluntary isometric contraction. Results: The peak torque per body weight and average peak torque were significantly higher in AD than in AP and NP (P < .01). The vastus medialis and rectus femoris maximal voluntary isometric contraction EMG activity were significantly higher in AD than in AP and NP (P < .01). The vastus lateralis maximal voluntary isometric contraction EMG activity was significantly higher in AD than in AP and NP (P < .01), and was significantly higher in AP than in NP (P < .05). Conclusions: These results indicate that the 3 different ankle positions affect the QF torque and EMG activity. In particular, AD position may be more efficient for improving QF strength than AP and NP position. Future studies should prove whether long-term duration QF isometric exercise effects muscle strength and functional performance in different ankle positions. [ABSTRACT FROM AUTHOR]

In healthy individuals, symmetrical lower-extremity movement is often assumed and calculated using discrete points during various tasks. However, measuring overall movement patterns using methods such as statistical parametric mapping (SPM) may allow for better interpretation of human movement. This study demonstrated the ability of SPMto assess interlimb differences in lower-extremity movement during 2 example tasks: running and landing. Three-dimensional motion analysis was used to determine sagittal and frontal plane lower-extremity joint angles in (1) young and older individuals during running and (2) patients with anterior cruciate ligament reconstruction and uninjured control athletes during landing. Interlimb differences within each group were compared using SPMand paired t tests on peak discrete angles. No differences between limbs were found between young and older runners using SPM. Peak ankle eversion and plantar flexion angles differed between limbs in young and older runners. Sagittal plane hip angle varied between limbs in uninjured control athletes. Frontal plane ankle angle and sagittal plane knee and hip angles differed between limbs in patients with anterior cruciate ligament reconstruction using SPM and discrete analysis. These data suggest that SPM can be useful to determine clinically meaningful interlimb differences during running and landing in multiple populations. [ABSTRACT FROM AUTHOR]

Walking balance is central to independent mobility, and falls due to loss of balance are a leading cause of death for people 65 years of age and older. Bipedal gait is typically unstable, but healthy humans use corrective torques to counteract perturbations and stabilize gait. Exoskeleton assistance could benefit people with neuromuscular deficits by providing stabilizing torques at lower-limb joints to replace lost muscle strength and sensorimotor control. However, it is unclear how applied exoskeleton torques translate to changes in walking kinematics. This study used musculoskeletal simulation to investigate how exoskeleton torques applied to the ankle and subtalar joints alter center of mass kinematics during walking. We first created muscle-driven walking simulations using OpenSim Moco by tracking experimental kinematics and ground reaction forces recorded from five healthy adults. We then used forward integration to simulate the effect of exoskeleton torques applied to the ankle and subtalar joints while keeping muscle excitations fixed based on our previous tracking simulation results. Exoskeleton torque lasted for 15% of the gait cycle and was applied between foot-flat and toe-off during the stance phase, and changes in center of mass kinematics were recorded when the torque application ended. We found that changes in center of mass kinematics were dependent on both the type and timing of exoskeleton torques. Plantarflexion torques produced upward and backward changes in velocity of the center of mass in mid-stance and upward and smaller forward velocity changes near toe-off. Eversion and inversion torques primarily produced lateral and medial changes in velocity in mid-stance, respectively. Intrinsic muscle properties reduced kinematic changes from exoskeleton torques. Our results provide mappings between ankle plantarflexion and inversion-eversion torques and changes in center of mass kinematics which can inform designers building exoskeletons aimed at stabilizing balance during walking. Our simulations and software are freely available and allow researchers to explore the effects of applied torques on balance and gait. Author summary: Walking balance is central to independent mobility, and falls due to loss of balance are a leading cause of death for people 65 years of age and older. Wearable robotic devices, or exoskeletons, could help people with reduced muscle strength and motor control avoid falls by providing stabilizing torques at lower-limb joints. However, it is currently unclear how exoskeleton torques change walking motions. In this study, we used computer simulation to investigate how exoskeleton torques applied to the ankle change the motion of the body's center of mass. We first created realistic simulations of walking using a biomechanically accurate model. We then simulated the effect of exoskeleton torques applied to the model that plantarflexed (i.e., extended), inverted, or everted the ankle. We found that plantarflexion torques moved the center of mass backwards or forwards, depending on when the torque was applied during the walking cycle. Plantarflexion torques also moved the center of mass upwards. Eversion and inversion torques produced left-right motions of the center of mass. Finally, we found that the force-generating properties of muscles in our model reduced the center of mass changes from exoskeleton torques. Our results can help exoskeleton designers create devices that stabilize walking balance. [ABSTRACT FROM AUTHOR]

This study investigated the impact of blood flow restriction (BFR) during treadmill walking on gait kinematics. Twenty-one participants completed one familiarisation and four experimental sessions, including two walking speeds (moderate [5.0 ± 0.3km·h−1] and fast [6.4 ± 0.4km·h−1]) and two occlusion conditions (BFR [60% of arterial occlusion pressure] and unrestricted). For each exercise intensity, the BFR session was performed first. Participants were instructed to walk as long as possible, with sessions capped at 20 min. Unrestricted sessions were time-matched, and the order of exercise intensity was randomised. Kinematics were collected over 10s every minute using retro-reflective markers affixed to specific body landmarks. Ratings of perceived exertion and discomfort were collected every two minutes. Blood samples were collected from the fingertip pre-exercise and the finger and toe post-exercise, and were analysed for lactate, electrolytes, and markers of cell-membrane damage. During the BFR sessions the cuffs remained inflated while the blood samples were collected. Fast-walk BFR sessions exhibited higher anterior trunk flexion (p = 0.001) and knee flexion during stance (p = 0.001) compared to all other sessions. Step width was increased during BFR sessions (p = 0.001), but no difference in step length (p = 0.300) or cadence (p = 0.922) were observed. The time required to elicit change in anterior trunk flexion and plantar-flexion angle at toe-off was shorter during BFR sessions (p = 0.024). The BFR sessions elicited the highest ratings of perceived exertion and discomfort, as well as blood lactate concentration (p ≤ 0.001). Application of BFR during moderate and fast treadmill walking modifies gait kinematics and exacerbates exercise-related sensations as well as blood lactate concentration. Applying blood flow restriction changes walking kinematics, causing an overall increase in anterior trunk flexion and knee flexion during stance while simultaneously reducing plantar-flexion angle at toe-off and ankle joint velocity. Applying blood flow restriction exacerbate exercise-related sensations of exertion and discomfort. Sample site does not influence the level of post-exercise blood lactate or markers of cell-membrane potential and damage. [ABSTRACT FROM AUTHOR]

Background: Deltoid ligament injuries occur in isolation as well as with ankle fractures and other ligament injuries. Both operative treatment and nonoperative treatment are used, but debate on optimal treatment continues. Likewise, the best method of surgical repair of the deltoid ligament remains unclear. Purpose: To determine the biomechanical role of native anterior and posterior components of the deltoid ligament in ankle stability and to determine the efficacy of simple suture versus augmented repair. Study Design: Controlled laboratory study. Methods: Ten cadaveric ankles (mean age, 51 years; age range, 34-64 years; all male specimens) were mounted on a 6 degrees of freedom robotic arm. Each specimen underwent biomechanical testing in 8 states: (1) intact, (2) anterior deltoid cut, (3) anterior repair, (4) tibiocalcaneal augmentation, (5) deep anterior tibiotalar augmentation, (6) posterior deltoid cut, (7) posterior repair, and (8) complete deltoid cut. Testing consisted of anterior drawer, eversion, and external rotation (ER), each performed at neutral and 25° of plantarflexion. A 1-factor, random-intercepts, linear mixed-effect model was created, and all pairwise comparisons were made between testing states. Results: Cutting the anterior deltoid introduced ER (+2.1°; P =.009) and eversion laxity (+6.2° of eversion; P <.001) at 25 degrees of plantarflexion. Anterior deltoid repair restored native ER but not eversion. Tibiocalcaneal augmentation reduced eversion laxity, but tibiotalar augmentation provided no additional benefit. The posterior deltoid tear showed no increase in laxity. Complete tear introduced significant anterior translation, ER, and eversion laxity (+7.6 mm of anterior translation, +13.8° ER and +33.6° of eversion; P <.001). Conclusion: A complete deltoid tear caused severe instability of the ankle joint. Augmented anterior repair was sufficient to stabilize the complete tear, and no additional benefit was provided by posterior repair. For isolated anterior tear, repair with tibiocalcaneal augmentation was the optimal treatment. Clinical Relevance: Deltoid repair with augmentation may reduce or avoid the need for prolonged postoperative immobilization and encourage accelerated rehabilitation, preventing stiffness and promoting earlier return to preinjury activity. [ABSTRACT FROM AUTHOR]

High magnitude loading from performing resistance-based exercise has been found to improve tendon strength and reduce symptoms of Achilles tendinopathy (AT) but is difficult to quantify without specialist equipment. Here, we assess the validity and reliability of a novel AT rehabilitation tool (the "PhysViz" system) compared to a "gold-standard" dynamometer for assessing plantarflexion maximal voluntary isometric contractions (MVIC). 41 participants aged 18–60 completed the study. A within-subject test–retest study design was used to examine and compare the validity and reliability of the two systems during plantarflexion MVICs. Test – retest reliability of the two methods were determined by calculating intra-class correlation coefficients (ICCs) and 95% confidence intervals. Method agreement was assessed with Bland – Altman Limits of Agreement (LoA) analysis. The PhysViz demonstrated excellent test–retest reliability; ICC, SEM and MDC were numerically comparable to the dynamometer (ICC 0.93 vs. 0.92; SEM 2.01 vs. 2.95 kg and MDC 5.58 vs. 8.18 kg, respectively), indicating that the novel system is valid and reliable for measuring plantarflexor MVICs. Future studies should address its utility in monitoring AT rehabilitative loading remotely over time. [ABSTRACT FROM AUTHOR]

Footwear interventions are a potential avenue to correct walking asymmetry in neurologic populations, such as stroke. However, the motor learning mechanisms that underlie the changes in walking imposed by asymmetric footwear are unclear. The objectives of this study were to examine symmetry changes during and after an asymmetric shoe height intervention in (1) vertical impulse and (2) spatiotemporal gait parameters and (3) joint kinematics, in healthy young adults Eleven healthy young adults (3 males, 8 females; 21.2 ± 3.1 years old) participated in this study. Participants walked on an instrumented treadmill at 1.3 m/s for four conditions: (1) a 5-minute familiarization with equal shoe height, (2) a 5-minute baseline with equal shoe height, (3) a 10-minute intervention, where participants walked with asymmetric shoe height with a 10 mm shoe insert in one shoe, and (4) a 10-minute post-intervention, where participants walked with equal shoe height. Asymmetry in kinetics and kinematics were used to identify changes during intervention and aftereffects, a hallmark of feedforward adaptation Participants did not alter vertical impulse asymmetry (p = 0.667) nor stance time asymmetry (p = 0.228). During the intervention, step time asymmetry (p = 0.003) and double support asymmetry (p < 0.001) were greater compared to baseline. Leg joint asymmetry during stance (Ankle plantarflexion: p < 0.001; Knee flexion: p < 0.001; Hip extension: p = 0.011) was greater during the intervention compared to baseline. However, changes in spatiotemporal gait variables and joint mechanics did not demonstrate aftereffects. Our results show that healthy human adults change gait kinematics, but not weight-bearing symmetry with asymmetrical footwear. This suggests that healthy humans prioritize maintaining vertical impulse by changing their kinematics. Further, the changes in gait kinematics are short-lived, suggesting feedback-based control, and a lack of feedforward motor adaptations • Kinetic asymmetry is not adapted with asymmetrical shoe height. • Gait kinematic asymmetry are altered with asymmetrical shoe height. • Gait kinematic asymmetry changes may be due to reactive learning mechanisms. [ABSTRACT FROM AUTHOR]

Vertical jump height is a widely used variable in sport science and physical education. This narrative review summarizes various numerical methods used to calculate vertical jump height. In force plate technology, the jump height is most commonly calculated using the flight time (FT) or the takeoff velocity (TOV), which provide only the distance traveled in the air and neglect the center of mass (CoM) elevation before the jump. However, CoM is already elevated before the takeoff, mainly due to plantar flexion of the ankles. Double integration methods can be used to circumvent this issue. In field-based testing, the "heel lift constant" can be added to flight height to more accurately determine the jump height according to the biomechanical definition (the vertical difference in body's CoM between standing position and the apex of the jump). A high degree of caution should be used when comparing the data from previous studies. [ABSTRACT FROM AUTHOR]

Historically, mangled extremities were generally treated with a primary amputation. Advancements in surgical repair and reconstruction have increased the possibility of salvage in the limbs damaged by high-energy trauma, with a reasonably functional outcome. The Mangled Extremity Severity Score is a useful guide for evaluating and managing a crushed limb. However, most literature does not support the practicality of any particular scoring system to discriminate between the limbs requiring amputation and those likely to be salvaged successfully. In young patients, without significant comorbidities and borderline injury scores, an earnest attempt at limb salvage should be made. The case report highlights how shared and timely decision-making coupled with the innovative use of the Ilizarov apparatus, in a seemingly distraught situation, led to successful salvage and restoration of function. [ABSTRACT FROM AUTHOR]

BACKGROUND: Analysis of performance asymmetries has indicated that the right and left cerebral hemispheres are specialized for specific functions of motor control. AIM: In the current investigation, we aimed to evaluate the effect of leg dominance on electrical activation of the plantar flexor muscles in responses to unanticipated stance perturbations in a state muscular fatigue of the dominant leg. METHOD: Fatigue was induced through ankle isometric contraction targeting 40% of maximum voluntary contraction. Muscle activation of the triceps surae of the dominant and non-dominant legs were compared in reactive responses to unanticipated load released from the trunk, leading to forward body sway. Muscular responses were analyzed in two states: pre-fatigue and fatigue of the triceps surae muscles of the dominant leg only. RESULTS: Analysis of magnitude of muscular activation for balance recovery following perturbations revealed fatigue-related compensatory activation in the lateral gastrocnemius muscle, as indicated by over-activation of the non-fatigued/non-dominant leg to compensate for the low muscular activation of the dominant/fatigued leg in the unilateral fatigue state. CONCLUSION: Compensatory behavior between the legs was not evident in the medial gastrocnemius and soleus muscles. Lack of effects related to leg dominance indicates that footedness did not affect automatic muscular responses either in the pre-fatigue or fatigue states. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Functional ankle instability is characterized by proprioceptive deficits, decreased neuromuscular control, and recurrent ankle sprains, which severely affect the patient’s daily activities. Proprioception as an important aspect of functional ankle instability, whether there is a deficit in proprioception compared to contralateral limbs and healthy individuals is not known. Therefore, this systematic review aims to analyze the proprioceptive characteristics of functional ankle instability. METHODS: We searched the CNKI, PubMed, Web of Science, EBSCO-host, Ovid, and EMbase databases from inception to February 2022 to collect observational studies about the proprioception characteristics of functional ankle instability, exposure to at least one proprioceptive deficit in kinesthesia, joint position sense, and force sense. Two researchers independently screened the articles according to the inclusion and exclusion criteria, and evaluated the quality of the included studies according to the Newcastle-Ottawa Scale and the cross-sectional study quality evaluation form developed by the American Institute for Healthcare Research and Quality, and extracted absolute errors relating kinesthesia, joint position sense, and force sense to set target. Metaanalysis was then performed using RevMan 5.3 software. RESULTS: A total of 26 observational studies were included, including 4 cohort studies, 6 case-control studies and 16 cross-sectional studies, all of which were of medium to high quality. Meta-analysis results showed that patients with unilateral functional ankle instability had inversion kinesthesia defects compared with the contralateral limbs and healthy people (SMD=0.53, 95%CI:0.36-0.71, P < 0.000 01). Compared with the contralateral limb, patients with unilateral functional ankle instability had the defect of inversion joint position sense (active vs. passive replication) (SMD=1.60, 95%CI:0.77-2.43, P=0.000 2). Compared with healthy people, unilateral functional ankle instability patients had the defect of inversion joint position sense (active vs. passive replication) (SMD=0.66, 95%CI:0.25-1.07, P=0.002). Compared with healthy people, unilateral functional ankle instability patients had the defect of active eversion joint position sense (SMD=3.68, 95%CI:1.85-5.52, P < 0.000 1). Compared with healthy people, unilateral functional ankle instability patients had the defect of passive eversion joint position sense (SMD=-0.61, 95%CI:-1.19 to -0.02, P=0.04). There was no significant difference between patients with unilateral functional ankle instability and healthy subjects in plantarflexion joint position sense (active vs. passive replication) (SMD=0.80, 95%CI:-0.19 to 1.79, P=0.11). There was no significant difference between patients with unilateral functional ankle instability and healthy subjects in dorsiflexion joint position sense (active vs. passive replication) (SMD=0.86, 95%CI:-0.01 to 1.74, P=0.05). Patients with unilateral functional ankle instability had coronal plant motion force sense deficits compared with healthy individuals (SMD=1.35, 95%CI:0.85 to 1.85, P < 0.000 01). Subgroup analysis showed that patients with unilateral functional ankle instability had greater eversion force sense error than those with inversion force sense error compared with the healthy population (P=0.44). CONCLUSION: Compared with the contralateral limbs, patients with unilateral functional ankle instability have the defects of inversion kinesthesia. Compared with healthy people, unilateral functional ankle instability patients have the defects of inversion kinesthesia, active and passive inversion joint position sense, active eversion joint position sense and force sense of inversion and eversion. [ABSTRACT FROM AUTHOR]

Background: Individualized, targeted, and intense training is the hallmark of successful gait rehabilitation in people post-stroke. Specifically, increasing use of the impaired ankle to increase propulsion during the stance phase of gait has been linked to higher walking speeds and symmetry. Conventional progressive resistance training is one method used for individualized and intense rehabilitation, but often fails to target paretic ankle plantarflexion during walking. Wearable assistive robots have successfully assisted ankle-specific mechanisms to increase paretic propulsion in people post-stroke, suggesting their potential to provide targeted resistance to increase propulsion, but this application remains underexamined in this population. This work investigates the effects of targeted stance-phase plantarflexion resistance training with a soft ankle exosuit on propulsion mechanics in people post-stroke. Methods: We conducted this study in nine individuals with chronic stroke and tested the effects of three resistive force magnitudes on peak paretic propulsion, ankle torque, and ankle power while participants walked on a treadmill at their comfortable walking speeds. For each force magnitude, participants walked for 1 min while the exosuit was inactive, 2 min with active resistance, and 1 min with the exosuit inactive, in sequence. We evaluated changes in gait biomechanics during the active resistance and post-resistance sections relative to the initial inactive section. Results: Walking with active resistance increased paretic propulsion by more than the minimal detectable change of 0.8 %body weight at all tested force magnitudes, with an average increase of 1.29 ± 0.37 %body weight at the highest force magnitude. This improvement corresponded to changes of 0.13 ± 0.03 N m kg− 1 in peak biological ankle torque and 0.26 ± 0.04 W kg− 1 in peak biological ankle power. Upon removal of resistance, propulsion changes persisted for 30 seconds with an improvement of 1.49 ± 0.58 %body weight after the highest resistance level and without compensatory involvement of the unresisted joints or limb. Conclusions: Targeted exosuit-applied functional resistance of paretic ankle plantarflexors can elicit the latent propulsion reserve in people post-stroke. After-effects observed in propulsion highlight the potential for learning and restoration of propulsion mechanics. Thus, this exosuit-based resistive approach may offer new opportunities for individualized and progressive gait rehabilitation. [ABSTRACT FROM AUTHOR]

The reliability of mechanical measures can be impacted by the protocol used, including factors such as joint angle and the sex of participants. This study aimed to determine the inter-day reliability of plantar flexor mechanical measures across ankle joint angles and contraction types and consider potential sex-specific effects. 14 physically-active individuals participated in two identical measurement sessions involving involuntary and voluntary plantar flexor contractions, at three ankle angles (10° plantarflexion (PF), 0° (anatomical zero (AZ)), and 10° dorsiflexion (DF)), while torque and surface EMG were recorded. The reliability of mechanical parameters of maximal voluntary torque (MVT), rate of torque development (RTD), electromechanical delay, and tendon stiffness were assessed using absolute and relative reliability measures. MVT measures were reliable across ankle angles. RTD measures showed good group level reliability and moderate reliability for an individual during the early phase of contraction across ankle angles. Explosive voluntary torque measures tended to be less reliable from 50 ms onward, with varied reliability across angles for late-phase RTD. Tendon stiffness demonstrated the best reliability at the DF angle. Sex-based differences in the reliability of tendon measures found that females had significantly different initial tendon length between testing sessions. Despite this, tendon excursion, force, and stiffness measures demonstrated similar reliability compared to males. Ankle angle changes influence the reliability of plantar flexor mechanical measurements across contraction types, particularly for voluntary contractions. These results highlight the importance of establishing potential protocol effects on measurement reliability prior to quantifying plantar flexor mechanical measures. [ABSTRACT FROM AUTHOR]

Resistance exercise on Earth commonly involves both body weight and external load. When developing exercise routines and devices for use in space, the absence of body weight is not always adequately considered. This study compared musculoskeletal load distribution during two flywheel resistance knee-extension exercises, performed in the direction of (vertical squat; S) or perpendicular to (horizontal leg press; LP) the gravity vector. Eleven participants performed these two exercises at a given submaximal load. Motion analysis and musculoskeletal modelling were used to compute joint loads and to simulate a weightless situation. The flywheel load was more than twice as high in LP as in S (p < 0.001). Joint moments and forces were greater during LP than during S in the ankle, hip and lower back (p < 0.01) but were similar in the knee. In the simulated weightless situation, hip and lower-back loadings in S were higher than corresponding values at Earth gravity (p ≤ 0.01), whereas LP joint loads did not increase. The results suggest that LP is a better terrestrial analogue than S for knee-extension exercise in weightlessness and that the magnitude and direction of gravity during resistance exercise should be considered when designing and evaluating countermeasure exercise routines and devices for space. [ABSTRACT FROM AUTHOR]

Introduction: Patients with diabetes are more likely to fall due to increased plantar pressure and decreased strength in the lower extremities. Objectives: To determine the influence of isometric ankle strength on dynamic foot plantar pressure in diabetes and non-diabetes participants. Methods: Twenty diabetes patients and twenty non-diabetes participants with age 28-54 years, height 150-182 cm, weight 48-90 kg, and BMI 25-54 kg/m2 participated in the study. The diabetes level was determined based on fasting plasma glucose levels. The resisted isometric muscle strength of the foot during dorsiflexion, plantar flexion, inversion, and eversion was measured using an electronic handheld dynamometer. The plantar pressure distribution during dynamic conditions was determined by using a 48.7x44.7 cm pressure platform. The outcome measures between diabetes and non-diabetes groups were statistically compared by student t-test. The correlation coefficient was determined by the Pearson correlation coefficient test. A p-value of less than 0.05 was considered significant. Result: The significant differences were found between diabetes and non-diabetes participants for the dorsiflexion (p=.048), plantarflexion (p=.031), inversion (p=.011), eversion (p=.024), peak pressure (p=.024), pressure per square inch (p=.012), pressure time integral (p=.014), and peak pressure gradient (p=.009). Significant relationships between resisted isometric ankle joint strength and foot plantar pressure for diabetes patients and non-diabetes participants were found. Conclusion: The present study's findings reflect the higher frequency of plantar pressure distribution and higher muscle weakness in diabetes patients than in non-diabetes participants. These findings suggested that pressure data could help us to customize therapy strategies for patients with diabetes and prescribe a proper exercise intervention's short-and long-term effects on gait biomechanics. [ABSTRACT FROM AUTHOR]

The countermovement jump is a popular measurement modality to evaluate muscle power in sports and exercise. Muscle power is essential to achieve a high jump, yet the well-coordinated movement of the body segments, which optimizes the stretch-shortening cycle (SSC) effects, is also required. Among the proposed explanations of SSC effects, this study investigated whether the ankle joint kinematics, kinetics, and muscle-tendon interaction depend on the level of jump skill and the jump task. Sixteen healthy males were grouped as a function of their jump height (High jumpers; greater than 50 cm, Low jumpers; less than 50 cm). They were instructed to jump with two intensities; light effort (20 % of their height) and maximal effort. Joint kinematics and kinetics of the lower limbs were analyzed using a 3-dimensional motion analysis system. The muscle-tendon interaction was investigated using B-mode real-time ultrasonography. As the jump intensity increased, all participants jumped with increased joint velocity and power. However, the high jumper shows less fascicle shortening velocity (-0.2 ± 0.1 m/s) than the low jumper group (-0.3 ± 0.1 m/s) and greater tendon velocity, which indicated the capability of elastic energy recoil. In addition, the delayed onset time of ankle extension in the high jumper implies better use of the catapult mechanism. The findings of this study showed that the muscle- tendon interaction differs depending on the jump skill level, suggesting a more efficient neuromuscular control in skilled jumpers. [ABSTRACT FROM AUTHOR]

Background: The heights obtained during the countermovement jump and drop jump tests have been measured by numerous studies using different calculation methods and pieces of equipment. However, the differences in calculation methods and equipment used have resulted in discrepancies in jump height being reported. Objectives: The aim of this systematic review was to examine the available literature pertaining to the different calculation methods to estimate the jump height during the countermovement jump and drop jump. Methods: A systematic review of the literature was undertaken using the SPORTDiscus, MEDLINE, CINAHL, and PubMed electronic databases, with all articles required to meet specified criteria based on a quality scoring system. Results: Twenty-one articles met the inclusion criteria, relating various calculation methods and equipment employed when measuring jump height in either of these two tests. The flight time and jump-and-reach methods provide practitioners with jump height data in the shortest time, but their accuracy is affected by factors such as participant conditions or equipment sensitivity. The motion capture systems and the double integration method measure the jump height from the centre of mass height at the initial flat foot standing to the apex of jumping, where the centre of mass displacement generated by the ankle plantarflexion is known. The impulse-momentum and flight time methods could only measure the jump height from the centre of mass height at the instant of take-off to the apex of jumping, thus, providing statistically significantly lower jump height values compared with the former two methods. However, further research is warranted to investigate the reliability of each calculation method when using different equipment settings. Conclusions: Our findings indicate that using the impulse-momentum method via a force platform is the most appropriate way for the jump height from the instant of take-off to the apex of jumping to be measured. Alternatively, the double integration method via a force platform is preferred to quantify the jump height from the initial flat foot standing to the apex of jumping. [ABSTRACT FROM AUTHOR]

Recent findings provided evidence that spinal regulatory mechanisms were involved in corticomuscular coherence (CMC) modulation between contraction types. Although their relative contributions could not be precisely identified, it was suggested that recurrent inhibition (RI) could modulate CMC by regulating the synchronization of spinal motoneuron activity. To confirm this hypothesis, concurrent modulations of RI and CMC for the soleus (SOL) were compared during submaximal isometric, shortening and lengthening plantar flexions. Submaximal contraction intensity was set at 50% of the maximal SOL EMG activity. CMC was computed in the time‐frequency domain between the Cz EEG electrode signal and the nonrectified SOL EMG signal. The RI was quantified through the paired Hoffmann (H) reflex technique by comparing the modulations of the test and conditioning H‐reflexes (H' and H1, respectively). Both beta‐band CMC and the ratio between H′ and H1 amplitudes were significantly lower in SOL during lengthening compared with isometric and shortening contractions. Furthermore, we observed a negative linear correlation between the RI and beta‐band CMC. Finally, a higher RI increase during lengthening contractions compared to either isometric or shortening ones was correlated with a larger decrease in CMC. Collectively, these novel findings provide robust evidence that the RI acts as a neural "filter" that contributes to the modulation of corticomuscular interactions between contraction types, possibly by disrupting the oscillatory muscle activation. [ABSTRACT FROM AUTHOR]

Purpose: We investigated the relationship between intramuscular adipose tissue (IntraMAT) and muscle stiffness (passive and mechanical) and lengthening in young individuals, hypothesizing that (1) passive muscle stiffness is negatively correlated with the IntraMAT content, and (2) the IntraMAT content is negatively correlated with mechanical changes in muscle stiffness and fascicle length during passive dorsiflexion. Methods: Twenty men and women (20.3 ± 1.3 years) participated in this study. Axial T1-weighted magnetic resonance imaging was performed at the thickest point of the medial gastrocnemius (MG) to measure the IntraMAT cross-sectional area (CSA) and muscle tissue CSA (units; cm2). The shear wave velocity (SWV) and fascicle length at the three ankle joint angles, namely 15° with plantarflexion (PF15), 0° with neutral position (NP), and 15° with dorsiflexion (DF15), were measured as parameters of muscle stiffness (unit; m/s) and lengthening (unit; cm) using ultrasound shear wave elastography and B-mode imaging. We further calculated the changes in SWV and fascicle length from PF15 to NP and from NP to DF15 as mechanical muscle stiffness and lengthening, respectively. Results: There was a relationship between IntraMAT CSA and absolute SWV at DF15 (r = − 0.47, P < 0.05). Further, a relationship was observed between IntraMAT CSA and change in SWV and fascicle length from NP to DF15 (r = − 0.47 and r = 0.59, P < 0.05); whereas no relationship was observed between changes in fascicle length and muscle SWV (r = − 0.23, P = 0.33). Conclusion: These results may indicate biomechanical and/or physiological associations between IntraMAT CSA and passive muscle stiffness. [ABSTRACT FROM AUTHOR]

Purpose: Resistance training (RT) is an effective countermeasure to combat physical deconditioning whereby localized hypoxia within the limb increases metabolic stress eliciting muscle adaptation. The current study sought to examine the influence of gravity on muscle oxygenation (SmO2) alongside vascular hemodynamic responses. Methods: In twelve young healthy adults, an ischemic occlusion test and seven minutes of low-intensity rhythmic plantarflexion exercise were used alongside superficial femoral blood flow and calf near-infrared spectroscopy to assess the microvascular vasodilator response, conduit artery flow-mediated dilation, exercise-induced hyperemia, and SmO2 with the leg positioned above or below the heart in a randomized order. Results: The microvascular vasodilator response, assessed by peak blood flow (798 ± 231 mL/min vs. 1348 ± 290 mL/min; p < 0.001) and reperfusion slope 10 s of SmO2 after cuff deflation (0.75 ± 0.45%.s-1 vs.2.40 ± 0.94%.s-1; p < 0.001), was attenuated with the leg above the heart. This caused a blunted dilatation of the superficial femoral artery (3.0 ± 2.4% vs. 5.2 ± 2.1%; p = 0.008). Meanwhile, blood flow area under the curve was comparable (above the heart: 445 ± 147 mL vs. below the heart: 474 ± 118 mL; p = 0.55) in both leg positions. During rhythmic exercise, the increase in femoral blood flow was lower in the leg up position (above the heart: 201 ± 94% vs. below the heart: 292 ± 114%; p = 0.001) and contributed to a lower SmO2 (above the heart: 41 ± 18% vs. below the heart 67 ± 5%; p < 0.001). Conclusion: Positioning the leg above the heart results in attenuated peak vascular dilator response and exercise-induced hyperemia that coincided with a lower SmO2 during low-intensity plantarflexion exercise. [ABSTRACT FROM AUTHOR]

A specific neurodynamic mobilization for the superficial fibular nerve (SFN) has been suggested in the reference literature for manual therapists to evaluate nerve mechanosensitivity in patients. However, no authors of biomechanical studies have examined the ability of this technique to produce nerve strain. Therefore, the mechanical specificity of this technique is not yet established. To test whether this examination and treatment technique produced nerve strain in the fresh frozen cadaver and the contribution of each motion to total longitudinal strain. Controlled laboratory study. Laboratory. A differential variable reluctance transducer was inserted in 10 SFNs from 6 fresh cadavers to measure strain during the mobilization. A specific sequence of plantar flexion, ankle inversion, straight-leg raise position, and 30° of hip adduction was applied to the lower limb. The mobilization was repeated at 0°, 30°, 60°, and 90° of the straight-leg raise position to measure the effect of hip-flexion position. Compared with a resting position, this neurodynamic mobilization produced a significant amount of strain in the SFN (7.93% ± 0.51%, P <.001). Plantar flexion (59.34% ± 25.82%) and ankle inversion (32.80% ± 21.41%) accounted for the biggest proportions of total strain during the mobilization. No difference was noted among different hip-flexion positions. Hip adduction did not significantly contribute to final strain (0.39% ± 10.42%, P >.05), although high variability among limbs existed. Ankle motion should be considered the most important factor during neurodynamic assessment of the SFN for distal entrapment. These results suggest that this technique produces sufficient strain in the SFN and could therefore be evaluated in vivo for correlation with mechanosensitivity. [ABSTRACT FROM AUTHOR]

The objective of this case series was to examine the feasibility of vibrotactile EMG-based biofeedback (BF) as a home-based intervention tool to enhance sensory information during everyday motor activities and to explore its effectiveness to induce changes in active ankle range of motion during gait in children with spastic cerebral palsy (CP). Ten children ages 6 to 13 years with spastic CP were recruited. Participants wore two EMG-based vibro-tactile BF devices for at least 4 hours per day for 1-month on the ankle and knee joints muscles. The device computed the amplitude of the EMG signal of the target muscle and actuated a silent vibration motor proportional to the magnitude of the EMG. Our results demonstrated the feasibility of the augmented sensory information of muscle activity to induce changes of the active ankle range of motion during gait for 6 children with an increase ranging from 8.9 to 51.6% compared to a one-month period without treatment. Preliminary findings of this case series demonstrate the feasibility of vibrotactile EMG-based BF and suggest potential effectiveness to increase active ankle range of motion, therefore serving as a promising therapeutic tool to improve gait in children with spastic CP. [ABSTRACT FROM AUTHOR]