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Context: Decreased muscle strength and balance in patients with functional ankle instability (FAI) can be effectively improved by ankle strength training. Low-load blood flow restriction (LL-BFR) training increases muscle size and strength, but there is limited evidence from studies on muscle strength and balance in FAI patients. Objective: To study the effects of LL-BFR training versus high-load training (HLT) on muscle strength and balance in FAI patients. Design: Randomized controlled trial. Participants: Forty-six young adults with a history of FAI. Interventions: Participants in the LL-BFR and HLT groups performed 4 sets (30 x 15 x 15 x 15) of ankle training at 20% to 40% of the one-repetition maximum and 70% to 85% one-repetition maximum, respectively, twice a week for 6 weeks. Main Outcome Measure(s): Plantar flexion, dorsiflexion, inversion, and eversion muscle strength, and the Y-balance test scores were assessed at baseline and after 3 and 6 weeks; the thickness of the tibialis anterior, triceps surae, and peroneus longus muscles were assessed at baseline and after 6 weeks. Results: Inversion, eversion, dorsiflexion, and plantar flexion muscle strength; tibialis anterior, triceps surae, and peroneus longus thickness; and Y-balance test scores were significantly increased in the LL-BFR group after 3 and 6 weeks compared with baseline (P < .05), with no significant difference between the LL-BFR and HLT groups after 6 weeks (P > .05). However, at the end of 3 weeks, eversion muscle strength and Y-balance test scores were significantly higher in the LL-BFR group than in the HLT group (P < .05). Conclusions: Over 6 weeks, LL-BFR training was as effective as HLT in improving ankle muscle strength, muscle thickness, and balance in FAI patients, but LL-BFR training improved the ankle eversion muscle strength and dynamic balance more than HLT did in the early stages of the intervention. This finding will provide a new intervention strategy for the clinical rehabilitation of FAI patients. [ABSTRACT FROM AUTHOR]

Spasticity is a common impairment within pediatric neuromusculoskeletal disorders. How spasticity contributes to gait deviations is important for treatment selection. Our aim was to evaluate the pathophysiological mechanisms underlying gait deviations seen in children with spasticity, using predictive simulations. A cluster analysis was performed to extract distinct gait patterns from experimental gait data of 17 children with spasticity to be used as comparative validation data. A forward dynamic simulation framework was employed to predict gait with either velocity- or force-based hyperreflexia. This framework entailed a generic musculoskeletal model controlled by reflexes and supraspinal drive, governed by a multiobjective cost function. Hyperreflexia values were optimized to enable the simulated gait to best match experimental gait patterns. Three experimental gait patterns were extracted: (1) increased knee flexion, (2) increased ankle plantar flexion, and (3) increased knee flexion and ankle plantar flexion when compared with typical gait. Overall, velocity-based hyperreflexia outperformed force-based hyperreflexia. The first gait pattern could mostly be explained by rectus femoris and hamstrings velocity-based hyperreflexia, the second by gastrocnemius velocity-based hyperreflexia, and the third by gastrocnemius, soleus, and hamstrings velocity-based hyperreflexia. This study shows how velocity-based hyperreflexia from specific muscles contributes to different spastic gait patterns, which may help in providing targeted treatment. [ABSTRACT FROM AUTHOR]

Purpose: This study examined the underlying mechanisms of postactivation potentiation and the time course of muscular- and neural-related variables. Methods: Fourteen trained males executed 4 sets of six 6-second maximum isometric conditioning plantar flexions, with 15 seconds and 2 minutes of interval between the contractions and sets, respectively. Peak twitch torque (TT), rate of torque development, time to peak torque, half relaxation time, and the neural-related variables of H-reflex and electromyogram, normalized to the maximum M-wave (H/M and RMS/M, respectively), were evaluated, as well as the level of the voluntary activation, assessed by the twitch interpolation technique. All neural-related variables were analyzed for the trial within each set when TT was maximal and for the trial within each set when the neural-related variable itself was maximal. Results: Compared with the baseline measures, TT and rate of torque development significantly increased in all sets (P <.001), whereas time to peak torque and half relaxation time significantly decreased in sets 1 to 4 and 2 to 4, respectively (P <.001). However, H/M and the RMS/M did not change for the repetition of each set for which the TT was maximal (P >.05). Interestingly, the within-set maximum H/M ratio of the lateral gastrocnemius muscle revealed a significant increase in all sets (P <.05), compared with the baseline measures. Conclusion: One set of 4 contractions with 6-second duration is sufficient to cause postactivation potentiation for most participants, whereas peak TT augmentation does not coincide with changes in the examined neural-related variables. Further experiments should consider the time lag on their maximal values and their inherent between-participants variability. [ABSTRACT FROM AUTHOR]

Introduction: Wearable exoskeletons are emerging technologies for providing movement assistance and rehabilitation for people with motor disorders. In this study, we focus on the specific gait pathology dropfoot, which is common after a stroke. Dropfoot makes it difficult to achieve foot clearance during swing and heel contact at early stance and often necessitates compensatory movements. Methods: We developed a soft ankle exoskeleton consisting of actuation and transmission systems to assist two degrees of freedom simultaneously: dorsiflexion and eversion, then performed several proof-of-concept experiments on non-disabled persons. The actuation system consists of two motors worn on a waist belt. The transmission system provides assistive force to the medial and lateral sides of the forefoot via Bowden cables. The coupling design enables variable assistance of dorsiflexion and inversion at the same time, and a force-free controller is proposed to compensate for device resistance. We first evaluated the performance of the exoskeleton in three seated movement tests: assisting dorsiflexion and eversion, controlling plantarflexion, and compensating for device resistance, then during walking tests. In all proof-of-concept experiments, dropfoot tendency was simulated by fastening a weight to the shoe over the lateral forefoot. Results: In the first two seated tests, errors between the target and the achieved ankle joint angles in two planes were low; errors of <1.5° were achieved in assisting dorsiflexion and/or controlling plantarflexion and of <1.4° in assisting ankle eversion. The force-free controller in test three significantly compensated for the device resistance during ankle joint plantarflexion. In the gait tests, the exoskeleton was able to normalize ankle joint and foot segment kinematics, specifically foot inclination angle and ankle inversion angle at initial contact and ankle angle and clearance height during swing. Discussion: Our findings support the feasibility of the new ankle exoskeleton design in assisting two degrees of freedomat the ankle simultaneously and show its potential to assist people with dropfoot and excessive inversion. [ABSTRACT FROM AUTHOR]

Total ankle arthroplasty (TAA) is used to treat symptomatic end-stage ankle arthritis (AA). However, little is known about TAA's effects on gait symmetry. Determine if symmetry changes from before surgery through two years following TAA utilizing the normalized symmetry index (NSI) and statistical parametric mapping (SPM). 141 patients with end-stage unilateral AA were evaluated from a previously collected prospective database, where each participant was tested within two weeks of surgery (Pre-Op), one year and two years following TAA. Walking speed, hip extension angle and moment, hip flexion angle, ankle plantarflexion angle and moment, ankle dorsiflexion angle, weight acceptance (GRF1), and propulsive (GRF2) vertical ground reaction forces were calculated for each limb. Gait symmetry was assessed using the NSI. A linear mixed effects model with a single response for each gait symmetry variable was used to examine the fixed effect of follow-up time (Pre-Op, Post-1 yr, Post-2 yr) and the random effect of participant with gait speed as a covariate in the model. A one-dimensional repeated measures analysis of variance (ANOVA) statistical parameter mapping (SPM) was completed to examine differences in the time-series NSI to determine regions of significant differences between follow-up times. Relative to Pre-Op values, GRF1, and GRF2 showed increased symmetry for discrete metrics and the time-series NSI across sessions. Hip extension moment had the largest symmetry improvement. Ankle plantarflexion angle was different between Pre-Op and Post-2 yr (p=0.010); and plantarflexion moment was different between Pre- Op and each post-operative session (p<0.001). The time-series Ankle Angle NSI was greater during the early stance phase in the Pre-Op session compared to Post-2 yr. Symmetry across most of the stance phase improved following TAA indicating that TAA successfully improves gait symmetry and future work should determine if these improvements restore symmetry to levels equivalent with health age-match controls. • At Post-1 yr and −2 yr, TAA patients have improved gait symmetry and gait speed. • Peak vertical GRF and Ankle plantarflexion moment symmetry improve following TAA. • Gait symmetry improves throughout most of the stance phase of gait after TAA. [ABSTRACT FROM AUTHOR]

An ankle-foot orthosis (AFO) with plantar flexion resistance (PFR) can improve the first rocker function during gait, but the incremental changes in the resistive moment on balance and gait have not been well identified. To investigate the effect of changing the PFR moment of dynamic AFO (DAFO) on measures of the center of pressure (COP) and clinical gait outcomes in individuals with post-stroke hemiparesis. In this randomized repeated measure study of 36 stroke individuals, the customized DAFO using foot drop ankle units set in three PFR situations (low, medium, and high) was evaluated. The balance parameters for COP measures were investigated by HUMAC® Balance & Tilt System. Gait parameters and ankle kinematics were recorded using the 3D motion analysis through force platform and optoelectronic system. The comparison was made using a parametric ANOVA test and the P value was set at 0.05 for statistical significance. Significant differences were observed for COP average velocity (1.30 ± 0.64, 1.10 ± 0.05, and 1.37 ± 0.43), COP path length (43.3 ± 4.6, 33.4 ± 4.3, and 36.3 ± 5.4), walking velocity (11.0 ± 3.1, 13.2 ± 4.4, and 9.9 ± 3.5), and cadence (31.5 ± 2.0, 33.0 ± 3.1, and 29.0 ± 1.6) respectively for low, medium and high PFR settings (P < 0.05). Except for the COP path length and cadence, posthoc multiple comparisons revealed significant differences between low and medium (P < 0.05) and medium and high (P < 0.05) PFR grades. PFR with medium resistance demonstrated near-normal maximal peak ankle dorsiflexion (mean deviation of 8 degrees, P < 0.05). Medium PFR grade should be encouraged since it can enhance balance parameters like path length and average velocity of COP, increase cadence and average velocity during gait, and improve maximal peak ankle dorsiflexion. • Changes in resistive moment of plantar-flexion affects gait and balance in stroke. • The influence of PFR moment on ankle kinematics, gait and balance was examined. • Dynamic AFOs with dorsiflexion assist Klenzak joints allow for adjustable PFR. • Moderate PFR setting may improve the ankle kinematics, gait and balance parameters. • High PFR may increase non-symmetrical ankle dorsiflexion during swing. [ABSTRACT FROM AUTHOR]

Introduction: Maximal acceleration and deceleration tasks are frequently required in team sports, often occurring rapidly in response to external stimuli. Accelerating and decelerating can be associated with lower limb injuries; thus, knowledge of joint mechanics during these tasks can improve the understanding of both human high performance and injury mechanisms. The current study investigated the fundamental differences in lower limb joint mechanics when accelerating and decelerating by directly comparing the hip, knee, and ankle joint moments and work done between the two tasks. Methods: Twenty participants performed maximal effort acceleration and deceleration trials, with three-dimensional marker trajectories and ground reaction forces collected simultaneously. Experimental data were combined with inverse dynamics analysis to compute joint moments and work. Results: Net joint work for all lower limb joints was positive during acceleration and negative during deceleration. This occurred because of significantly greater positive work production from the ankle and hip during acceleration and significantly greater negative work production from all joints during deceleration. The largest contributions to positive work during acceleration came from the ankle, followed by the hip and knee joints, whereas the largest contributions to negative work during deceleration came from the knee and hip joints, followed by the ankle. Peak joint moments were significantly greater when decelerating compared with accelerating, except for the peak ankle plantar flexion and hip flexion moments, which were significantly greater when accelerating. Conclusions: Our findings may help to guide training interventions, which aim to enhance the performance of acceleration and deceleration tasks, while also mitigating the associated injury risk. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine associations between patellofemoral pain (PFP) and musculoskeletal features (such as tendon structure and bone properties) in young (pre- and post-pubertal) female dancers. A total of 49 dancers participated in this study (mean age 13.6 ± 2.9; weight 47.0 ± 13.2; height 153.7 ± 12.9 and body mass index (BMI) 19.4 ± 3.1) and were assessed for the following factors: dance background and Tanner stage through interviews; ultrasonography assessments of bone properties and patellar tendon structure through ultrasonographic tissue characterization and quantitative ultrasound, respectively; and anthropometric measurements, muscle strength, range of motion (ROM), hypermobility and PFP through physical examinations. PFP was found in 49% of the participants. Post-pubertal dancers with no-PFP were found to have greater muscle strength, greater radial and tibial properties, and better tendon structure compared to pre-pubertal dancers with PFP and compared to pre-pubertal dancers with no-PFP [F(2, 41) = 18.64, p <.001; F(2, 41) = 20.46, p <.001; F(2, 41) = 33.06, p <.001; and, F(2, 41) = 6.02, p =.007, respectively]. Logistic regression showed that tibial bone properties and range of movement (ROM) in hip external rotation were significantly associated with PFP [odds ratio (OR) =.889 and OR = 2.653, respectively; Cox & Snell R2 =.701]. The study revealed a high prevalence of PFP among young dancers, with low bone properties and hyperjoint ROM emerging as the main factors that are related to PFP. These findings should be addressed by medical teams, athletic trainers, and dance teachers regarding the need for implementing modifications to dance training programmes and injury-prevention strategies in young pre-pubertal dancers. [ABSTRACT FROM AUTHOR]

Limited research exists on the relationship between aesthetic saut de chat performance and muscle-tendon unit (MTU) characteristics of dancers. We developed a weighted parameter ranking (WPR) tool to incorporate aesthetic leaping aspects (i.e., height, peak split angle, average trunk angle and trunk angle range) for correlation with MTU properties. The purpose was to identify the relationship of saut de chat WPR and leap height with maximal plantarflexion strength, medial gastrocnemius (MG) stiffness, Achilles tendon (AT) stiffness and relative peak power (PP). Dancers (n = 18) performed maximal plantarflexion, short-range stretches and isometric ramping contractions on a dynamometer equipped with ultrasound to determine strength, MG stiffness and AT stiffness, respectively. Subjects then performed saut de chat leaps atop force platforms surrounded by motion capture cameras. A principal component analysis (PCA) was performed to compare WPR variable weightings with PCA results and rankings. Moderate–strong relationships were identified among WPR, maximal plantarflexion strength, MG stiffness and PP. Strong–very strong relationships were also identified between leap height and maximal plantarflexion strength, MG stiffness, AT stiffness, peak split angle and PP. A very strong correlation existed between PCA rankings and WPRs. Practitioners may consider developing strength and power capabilities in dancers to improve leaping. [ABSTRACT FROM AUTHOR]

The peroneus longus graft has gained much attention in recent years as a reliable autograft for primary ACL surgery. Critics have voiced concerns related to its impact on ankle biomechanics. The current review aims to synthesize the available literature on ankle biomechanics after peroneus harvest. The quantum of evidence available shows that PL harvest does not significantly impact ankle eversion or plantarflexion strength. Its impact on gait needs to be studied more deeply before any significant conclusions can be drawn. [ABSTRACT FROM AUTHOR]

The production of triceps surae plantarflexion moment is complex in that the Achilles tendon moment arm affects the Achilles tendon force by determining the muscle length change and shortening velocity during ankle rotation. In addition, there is evidence for associations between the sizes of muscles and their moment arm at the joints they span. These relationships between muscle architecture and tendon moment arm ultimately affect the muscle's force generating capacity and are thus important for understanding the roles played by muscles in producing locomotion. The purpose of this study was to investigate in vivo the relationship between architecture of two plantarflexors and the Achilles tendon moment arm in a healthy adult population. Ultrasound-based measurements were made of the architecture (fascicle length, muscle volume, physiological cross-sectional area, and anatomical cross-sectional area) of the lateral and medial gastrocnemius and the Achilles tendon moment arm was assessed using a technique that combined ultrasound imaging and motion analysis. Positive correlations were observed between the length (r = 0.499, p = 0.049) and size variables (muscle volume r = 0.621, p = 0.010; ACSA r = 0.536, p = 0.032) of the lateral gastrocnemius and the Achilles tendon moment arm, but correlations were only observed for size variables (muscle volume r = 0.638, p = 0.008; PCSA r = 0.525, p = 0.037; ACSA r = 0.544, p = 0.029), and not the length, of the medial gastrocnemius. These findings suggest lateral gastrocnemius adapts to moment arms to maintain force production throughout the range of motion across individuals, while the medial gastrocnemius does not and is thus better suited for static force generation. [ABSTRACT FROM AUTHOR]

Background: In recent decades, early rehabilitation after Achilles tendon rupture (ATR) repair has been proposed. The aim of this prospective cohort study was to compare different immobilisation durations in order to determine the optimal duration after open surgery for ATR repair. Methods: This study included 1088 patients (mean age, 34.9 ± 5.9 years) who underwent open surgery for acute ATR repair. The patients were categorised into four groups (A, B, C, and D) according to postoperative immobilisation durations of 0, 2, 4, and 6 weeks, respectively. All patients received the same suture technique and a similar rehabilitation protocol after brace removal,; they were clinically examined at 2, 4, 6, 8, 10, 12, 14, and 16 weeks postoperatively, with a final follow-up at a mean of 19.0 months. The primary outcome was the recovery time for the one-leg heel-rise height (OHRH). Secondary outcomes included the time required to return to light exercise (LE) and the recovery times for the range of motion (ROM). Data regarding the surgical duration, complications, the visual analogue scale (VAS) score for pain, the Achilles tendon Total Rupture Score (ATRS), and the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale score were also collected. Results: The recovery times for OHRH, LE, and ROM were significantly shorter in groups A and B than in groups C and D (P < 0.001). The VAS scores decreased over time, reaching 0 in all groups by 10 weeks. The mean scores in groups A and B were higher than those in the other groups at 2 and 4 weeks (P < 0.001), whereas the opposite was true at 8 weeks (P < 0.001). ATRS and the AOFAS Ankle-Hindfoot scale score increased across all groups over time, showing significant between-group differences from weeks 6 to 16 (P < 0.001) and weeks 6 to 12 (P < 0.001). The mean scores were better in groups A and B than in groups C and D. Thirty-eight complications (3.5%) were observed, including 20 re-ruptures and 18 superficial infections. All complications were resolved at the last follow-up, with no significant between-group differences. Conclusions: Immobilisation for 2 weeks after open surgery for ATR repair may be the optimal strategy for early rehabilitation with relatively minimal pain and other complications. Trial registration: ClinicalTrials.gov (NCT04663542). [ABSTRACT FROM AUTHOR]

The effect of gait feedback training for older people remains unclear, and such training methods have not been adapted in clinical settings. This study aimed to examine whether inertial measurement unit (IMU)-based real-time feedback gait for older inpatients immediately changes gait parameters. Seven older inpatients (mean age: 76.0 years) performed three types of 60-s gait trials with real-time feedback in each of the following categories: walking spontaneously (no feedback trial); focused on increasing the ankle plantarflexion angle during late stance (ankle trial); and focused on increasing the leg extension angle, which is defined by the location of the ankle joint relative to the hip joint in the sagittal plane, during late stance (leg trial). Tilt angles and accelerations of the pelvis and lower limb segments were measured using seven IMUs in pre- and post-feedback trials. To examine the immediate effects of IMU-based real-time feedback gait, multiple comparisons of the change in gait parameters were conducted. Real-time feedback increased gait speed, but it did not significantly differ in the control (p = 0.176), ankle (p = 0.237), and leg trials (p = 0.398). Step length was significantly increased after the ankle trial (p = 0.043, r = 0.77: large effect size). Regarding changes in gait kinematics, the leg trial increased leg extension angle compared to the no feedback trial (p = 0.048, r = 0.77: large effect size). IMU-based real-time feedback gait changed gait kinematics immediately, and this suggests the feasibility of a clinical application for overground gait training in older people. [ABSTRACT FROM AUTHOR]

We report a first case of hallux rigidus successfully treated in an elderly patient by intra-articular infiltration of cross-linked hyaluronic acid (HA) 21 mg/mL with mannitol (Desirial Plus) and review the previous literature on the different compositions of HA infiltrative treatment applied to hallux rigidus. A 77-year-old female patient with moderate unilateral pain of 6 months of evolution and stiffness of the movement of the first metatarsophalangeal joint of the left foot, corresponding to grade 2 of the classification proposed by Coughlin and Shurnas. The objective of the study was to perform a pilot test to (a) evaluate the correct technique of intra-articular infiltration as well as (b) the use of a commercial cross-linked HA 21 mg/mL with mannitol, to a voluntary patient diagnosed with hallux rigidus. A single cross-linked HA infiltration is applied to the first metatarsophalangeal joint with an administered amount of 1 mL. The loaded dorsiflexion, the unloaded dorsiflexion, and the unloaded plantarflexion angles of the first metatarsophalangeal joint improved from 15°, 20°, and 10°, respectively, before injection to 45°, 52°, and 22°, respectively, at 14 days after injection. Moreover, these improvements maintained until the final follow-up (400 days). The intensity of pain, according to the visual analog scale, improved from 7 of 10 before the injection, passing through 4 of 10 at 14 days after the injection, to 1 of 10 at 60 days after the injection. Cross-linked HA 21 mg/mL with mannitol improves symptomatology, joint mobility of the first metatarsophalangeal joint, and quality of life in the patient with stiff hallux submitted to the pilot test. These effects have been maintained for more than 14 months. [ABSTRACT FROM AUTHOR]

Individuals with neuromuscular pathologies are often prescribed an ankle-foot orthosis (AFO) to improve their gait mechanics by decreasing pathological movements of the ankle and lower limb. AFOs can resist or assist excessive or absent muscular forces that lead to tripping, instability, and slow inefficient gait. However, selecting the appropriate AFO with mechanical characteristics, which limit pathological ankle motion in certain phases of the gait cycle while facilitating effective ankle movement during other phases, requires careful clinical decision-making. The aim of this study is to propose an explicit methodology for the adjustment of multi-function articulated AFOs in clinical settings. A secondary aim is to outline the evidence supporting this methodology and to identify gaps in the literature as potential areas for future research. An emerging class of AFO, the multi-function articulated AFO, offers features that permit more comprehensive, iterative, and reversible adjustments of AFO ankle alignment and resistance to ankle motion. However, no standard method exists for the application and optimization of these therapeutic devices in the clinical setting. Here we propose an evidence-guided methodology applicable to the adjustment of multi-function articulated AFOs in the clinical setting. Characteristic load-deflection curves are given to illustrate the idealized yet complex resistance-angle behavior of multi-function articulated AFOs. Research is cited to demonstrate how these mechanical characteristics can help mitigate specific pathologic ankle and knee kinematics and kinetics. Evidence is presented to support the effects of systematic adjustment of high resistance, alignable, articulated AFOs to address many typical pathomechanical patterns observed in individuals with neuromuscular disorders. The published evidence supporting most decision points of the algorithm is presented with identified gaps in the evidence. In addition, two hypothetical case examples are given to illustrate the application of the method in optimizing multi-function articulated AFOs for treating specific gait pathomechanics. This method is proposed as an evidence-guided systematic approach for the adjustment of multi-function articulated AFOs. It utilizes observed gait deviations mapped to specific changes in AFO alignment and resistance settings as a clinical tool in orthotic treatment for individuals with complex neuromuscular gait disorders. [ABSTRACT FROM AUTHOR]

In progressive collapsing foot deformity (PCFD), the goal of surgery is to obtain a well-balanced plantigrade foot. It remains unclear if restoration of the alignment and subsequent improvement in radiological parameters is associated with improved patient-reported outcome measures (PROMs). The aim of the current systematic review was to investigate whether there is a correlation between radiographic assessment and PROMs in patients treated surgically for flexible PCFD. The study was conducted in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement guidelines. A comprehensive literature search was performed in Pubmed, EMBASE, Cochrane Central Register of Controlled Trails (CENTRAL), and KINAHL. We included all the studies reporting both PROMs and radiological outcomes in patients treated surgically for PCFD. The quality of the included studies was assessed using the Joanna Briggs Institute (JBI) Critical Appraisal tool. Six retrospective studies were included. Radiological parameters related to forefoot plantarflexion were associated with statistically significant differences in postoperative PROMs. A neutral hindfoot and midfoot position was positively correlated with postoperative PROMs but a statistically significant difference could not be established in all studies. The medial arch height was positively correlated with PROMs, but in one study this was the case only in revision surgeries. The literature so far suggests restoration of the alignment may be associated with improved PROMs. Future prospective studies that investigate possible radiological and clinical correlations in PCFD surgery are needed. III. [ABSTRACT FROM AUTHOR]

[Purpose] The purpose of this study was to compare the effectiveness of the Structural Diagnosis and Management (SDM) approach with Myofascial Release (MFR) in improving plantar heel pain, ankle range of motion, and disability. [Subjects] Sixty-four subjects, aged 30–60 years, with a diagnosis of plantar heel pain, plantar fasciitis, or calcaneal spur by a physician according to ICD-10, were equally allocated to the MFR (n = 32) and SDM (n = 32) groups by hospital randomization and concealed allocation. [Methods] In this assessor-blinded randomized clinical trial, the control group performed MFR to the plantar surface of the foot, triceps surae, and deep posterior compartment calf muscles, while the experimental group performed a multimodal approach utilizing the SDM concept for 12 sessions over 4 weeks. Both groups also received strengthening exercises, ice compression, and ultrasound therapy. Pain, activity limitations and disability were assessed as primary outcomes using the Foot Function Index (FFI) and Range of motion (ROM) assessment of the ankle dorsiflexors and plantar flexors using a universal goniometer. Secondary outcomes were measured using the Foot Ankle Disability Index (FADI) and a 10-point manual muscle testing process for the ankle dorsiflexors and plantar flexors. [Results] Both MFR and SDM groups exhibited significant improvements from baseline in all outcome variables, including pain, activity level, disability, range of motion, and function after the 12-week intervention period (p <.05). The SDM group showed more improvements than MFR for FFI pain (p <.01), FFI activity (p <.01), FFI (p <.01) and FADI (p = <.01). [Conclusion] Both MFR and SDM approaches are effective in reducing pain, improving function, ankle range of motion, and reducing disability in plantar heel pain, however, the SDM approach may be a preferred treatment option. [ABSTRACT FROM AUTHOR]

Stretch-shortening cycles (SSCs) outperform shortening contractions preceded by isometric contractions in terms of enhanced force/torque, work, and power production during shortening. This so-called SSC effect is presumably related to the active muscle stretch before shortening in SSCs. However, it remains unclear whether the effects of stretch-induced higher preload level or stretch-induced history dependence maximize the SSC effect. Therefore, we analyzed fascicle behavior, muscle-tendon unit (MTU) shortening work, and torque/force (n = 12 participants) via ultrasound and dynamometry during electrically stimulated submaximal plantar flexion contractions from 10° plantarflexion to 15° dorsiflexion. To elucidate the effects of preload level and preload modality (i.e., contraction type) on shortening performance, muscle-tendon unit shortening was preceded by fixed-end (SHO), active stretch (SSC), and preload-matched fixed-end (MATCHED) contractions. Before shortening, MATCHED and SCC had the same preload level (1% torque difference), similar joint position, and muscle fascicle lengths. Compared with SHO, shortening work was significantly (P < 0.001, partial η2 = 0.749) increased by 85% and 55% for SSC and MATCHED, respectively, with SSC shortening work being significantly higher than MATCHED (P = 0.016). This indicates that preload contributes by 65% to the overall SSC effect so that 35% needs to be referred to stretched-induced history-dependent mechanisms. In addition, SSC showed larger fascicle forces at the end of shortening (P < 0.001) and 20% less depressed isometric torque following shortening compared with MATCHED (P < 0.001). As potential decoupling effects by the series elastic element were controlled by matching the preload levels, we conclude that the difference between SSC and MATCHED is related to stretch-induced long-lasting history-dependent effects. NEW & NOTEWORTHY: Using a torque-matched preload protocol, we found that 2/3 of the performance enhancement in muscle-tendon unit stretch-shortening cycles (SSCs) is caused by the increased preload level. The remaining 1/3 is owed to the long-lasting history-dependent effects triggered during the stretch in SSCs. This increased performance output is attributed to passive elastic structures within the contractile element that do not require additional muscle activation, therefore contributing to the higher efficiency of the neuromuscular system in SSCs. [ABSTRACT FROM AUTHOR]

Dynamic stretching (DS) is performed as a warm-up to improve the range of motion and athletic performance. However, the effect of different amounts of DS on muscle performance remains unclear. This study investigated the effects of DS repetitions with one or four sets of 30 s on musculotendinous extensibility and muscle strength. Fourteen healthy men (23.6 ± 1.5 years) underwent DS to ankle plantar flexors for one set (fifteen repetitions) or four sets after warm-up. The maximal ankle dorsiflexion angle, musculotendinous stiffness (MTS), passive torque, peak plantarflexion torque during maximal isometric contraction, and muscle temperature were measured before and after stretching. A significant effect of time was observed on the maximal ankle dorsiflexion angle, MTS, passive torque, and muscle temperature (p < 0.001). However, no interactions or effects between the conditions were observed. After DS, the maximal ankle dorsiflexion angle and muscle temperature significantly increased (p < 0.01), while the MTS and passive torque significantly decreased (p < 0.01). The maximal muscle strength showed no significant effects or interactions (p = 0.198−0.439). These results indicated that one and four sets of DS effectively increased musculotendinous extensibility. Thus, one set of DS may have similar effects as a warm-up before four sets of DS. [ABSTRACT FROM AUTHOR]

Total ankle arthroplasty (TAA) improves gait symmetry in patients with unilateral end‐stage ankle arthritis but has not been studied in patients undergoing bilateral TAA (B‐TAA), and few studies compare TAA patients to control subjects. The purpose of this study was to compare gait symmetry in U‐TAA and B‐TAA patients and healthy controls. Using prospective databases, 19 unilateral and 19 bilateral ankle arthritis patients undergoing TAA were matched to 19 control subjects by age, sex, and BMI. The Normalized Symmetry Index (NSI) was determined for joint mechanics and ground reaction forces (GRF) during walking trials at a single visit for controls and preoperatively and 1 to 2 years postoperatively for TAA patients. Data was analyzed using linear mixed‐effects models to determine differences among time points and cohorts at a significance of α = 0.05. Following surgery, B‐TAA and U‐TAA experienced improved peak plantarflexion moment symmetry (p = 0.017) but remained less symmetric than controls. B‐TAA patients had more symmetry than U‐TAA patients during peak weight acceptance GRF (p = 0.002), while U‐TAA patients had greater peak dorsiflexion symmetry than B‐TAA patients. TAA patients demonstrated more asymmetry compared to control subjects for all outcome measures. There was no significant impact of TAA on gait symmetry for GRF or peak ankle angles, and neither U‐TAA nor B‐TAA was consistently associated with higher gait symmetry. These results indicate that TAA improves symmetry during peak plantarflexion moment, and that significant gait asymmetry persists for B‐TAA and U‐TAA patients compared to healthy participants. [ABSTRACT FROM AUTHOR]

Previous research has demonstrated that oral contraceptive (OC) users have enhanced cardiorespiratory responses to arm metaboreflex activation (i.e., postexercise circulatory occlusion, PECO) and attenuated pressor responses to leg passive movement (PM) compared to non‐OC users (NOC). We investigated the cardiorespiratory responses to arm or leg metaboreflex and mechanoreflex activation in 32 women (OC, n = 16; NOC, n = 16) performing four trials: 40% handgrip or 80% plantarflexion followed by PECO and arm or leg PM. OC and NOC increased mean arterial pressure (MAP) similarly during handgrip, plantarflexion and arm/leg PECO compared to baseline. Despite increased ventilation (VE) during exercise, none of the women exhibited higher VE during arm or leg PECO. OC and NOC similarly increased MAP and VE during arm or leg PM compared to baseline. Therefore, OC and NOC were similar across pressor and ventilatory responses to arm or leg metaboreflex and mechanoreflex activation. However, some differences due to OC may have been masked by disparities in muscle strength. Since women increase VE during exercise, we suggest that while women do not display a ventilatory response to metaboreflex activation (perhaps due to not reaching a theoretical metabolite threshold to stimulate VE), the mechanoreflex may drive VE during exercise in women. [ABSTRACT FROM AUTHOR]

BACKGROUND: Patients with Parkinson's disease frequently experience problems with balance and gait. OBJECTIVE: This study examined the influences of regular ankle isokinetic muscle strength training on muscle strength and balance ability amongst elderly women with mild Parkinson's disease. METHODS: A total of 55 elderly women with mild Parkinson's disease were randomly divided into the experimental group (n = 28) and the control group (n = 27) for 16 weeks. The experimental group was trained for 16 weeks by using isokinetic muscle strength training. RESULTS: After 16 weeks of training in the experimental group, the peak torque (PT) of ankle (average of the left and right sides) dorsiflexion, plantarflexion, eversion and inversion, and the standing balance index revealed that the left and right stability and overall stability indexes significantly increased by 25.9%, 43.5%, 62.7%, 82.8%, 37.1% and 32.2%, respectively (p < 0.05). The experimental group exhibited significantly increased PT of ankle dorsiflexion, plantarflexion, eversion and inversion. Moreover, the left and right stability and overall stability indexes were significantly improved compared with those of the control group (p < 0.05). This study found a linear regression relationship between the PT of ankle inversion and overall stability index. CONCLUSION: This study determined that ankle isokinetic muscle strength training improved ankle dorsiflexion, plantarflexion, eversion and inversion muscle strength, and balance ability amongst elderly women with mild Parkinson's disease. However, it did not improve stability in the anterior and posterior directions. Ankle inversion muscle strength is more likely to affect overall balance. [ABSTRACT FROM AUTHOR]

\nHIGHLIGHTSMasters runners are an increasing proportion of the running community. The most significant musculoskeletal changes in runners occur after the age of 50 in addition to changes in injury rates and types, the most common being Achilles tendinopathy (AT). Previous evidence has suggested similarities between risk factors for AT and age-related changes that are focused at the hip and the ankle during the propulsive stage of running. The purpose of this study was to investigate biomechanical and peak torque association to AT in masters runners. Thirty-two masters runners over age 50 with AT (60.31 ± 8.37, n = 16) and without (59.94 ± 4.95 n = 16) were included. 3D motion capture and force plates were used to assess running biomechanics. A motor-driven dynamometer was used to assess isokinetic peak torque production. No significant differences in running biomechanics were found between masters runners with and without AT. Hip peak isokinetic torque production was found to be significantly less in masters runners with AT, but no significant differences in ankle plantarflexion peak isokinetic torque production were found. Masters runners with AT may be able to adapt their running biomechanics and muscular torque production during submaximal running efforts. Masters runners with Achilles tendinopathy do not demonstrate differences in peak hip extension moments during the stance phase of running during submaximal efforts compared to healthy masters runners.Masters runners with Achilles tendinopathy do not demonstrate differences in peak ankle plantarflexion moments during the stance phase of running during submaximal efforts compared to healthy masters runners.Masters runners with Achilles tendinopathy do not demonstrate differences in peak ankle plantarflexion concentric or eccentric isokinetic torque compared to healthy masters runners.Masters runners with Achilles tendinopathy demonstrate differences in peak hip extension concentric and eccentric isokinetic torque compared to healthy masters runners.Masters runners with Achilles tendinopathy do not demonstrate differences in peak hip extension moments during the stance phase of running during submaximal efforts compared to healthy masters runners.Masters runners with Achilles tendinopathy do not demonstrate differences in peak ankle plantarflexion moments during the stance phase of running during submaximal efforts compared to healthy masters runners.Masters runners with Achilles tendinopathy do not demonstrate differences in peak ankle plantarflexion concentric or eccentric isokinetic torque compared to healthy masters runners.Masters runners with Achilles tendinopathy demonstrate differences in peak hip extension concentric and eccentric isokinetic torque compared to healthy masters runners. [ABSTRACT FROM AUTHOR]

Objective: To determine whether acupotomy ameliorates immobilization-induced muscle contracture and fibrosis via Wnt/β-catenin signaling pathway. Methods: Thirty Wistar rats were randomly divided into 5 groups (n=6) by a random number table, including control, immobilization, passive stretching, acupotomy, and acupotomy 3 weeks (3-w) groups. The rat model of gastrocnemius contracture was established by immobilizing the right hind limb in plantar flexion for 4 weeks. Rats in the passive stretching group received passive stretching at gastrocnemius, a daily series of 10 repetitions for 30 s each at 30-s intervals for 10 consecutive days. Rats in the acupotomy and acupotomy 3-w groups received acupotomy once and combined with passive stretching at gastrocnemius a daily series of 10 repetitions for 30 s each at 30-s intervals for 10 consecutive days. Additionally, rats in the acupotomy 3-w group were allowed to walk freely for 3 weeks after 10-day therapy. After treatment, range of motion (ROM), gait analysis [i.e., paw area, stance/swing and maximum ratio of paw area to paw area duration (Max dA/dT)], gastrocnemius wet weight and the ratio of muscle wet weight to body weight (MWW/BW) were tested. Gastrocnemius morphometric and muscle fiber cross-sectional area (CSA) were assessed by hematoxylin-eosin staining. Fibrosis-related mRNA expressions (i.e., Wnt 1, β-catenin, axin-2, α-smooth muscle actin, fibronectin, and types I and III collagen) were measured using real-time quantitative polymerase chain reactions. Wnt 1, β-catenin and fibronectin concentrations were measured by enzyme-linked immunosorbent assay. Types I and III collagen in the perimysium and endomysium were analyzed using immunofluorescence. Results: Compared with the control group, ROM, gait function, muscle weight, MWW/BW and CSA were significantly decreased in the immobilization group (all P<0.01), while protein levels of types I and III collagen, Wnt 1, β-catenin, fibronectin and mRNA levels of fibrosis-related genes were obviously increased (all P<0.01). Treatment with passive stretching or acupotomy restored ROM and gait function and increased muscle wet weight, MWW/BW and CSA (all P<0.05), while protein expression levels of Wnt 1, β-catenin, fibronectin, types I and III collagen and mRNA levels of fibrosis-related genes were remarkably declined compared with the immobilization group (all P<0.05). Compared with passive stretching group, ROM, gait function, MWW was remarkably restored (all P<0.05), and mRNA levels of fibrosis-related genes as well as protein expression levels of Wnt 1, β-catenin, fibronectin, types I and III collagen in the acupotomy group were obviously decreased (all P<0.05). Compared with the acupotomy group, ROM, paw area, Max dA/dT, and MWW were restored (all P<0.05), and mRNA levels of fibrosis-related genes along with protein levels of Wnt 1, β-catenin, fibronectin, types I and III collagen in the acupotomy 3-w group were decreased (P<0.05). Conclusion: Improvements in motor function, muscle contractures, and muscle fibrosis induced by acupotomy correlates with the inhibition of Wnt/β-catenin signaling pathway. [ABSTRACT FROM AUTHOR]

Mobility declines in older adults can be determined through monitoring longitudinal changes in gait speed. We examined longitudinal changes [in] ankle proprioception among those with and without baseline lower extremity numbness to develop a better understanding of mobility declines in healthy older adults. Participants included 568 adults (52.8% women) aged 60–98 years from the Baltimore Longitudinal Study of Aging. Larger ankle proprioception decreases during plantar flexion were found in the participants with lower extremity numbness compared with those without numbness (p =.034). Among participants with lower extremity numbness, slower baseline speeds from both usual and fast pace gait were associated with performance decline in ankle proprioception measured during ankle dorsiflexion (p =.039 and p =.004, respectively). Assisting older adults, especially those with lower extremity numbness, to maintain and improve ankle proprioception may help prevent mobility declines that have previously been considered age related. [ABSTRACT FROM AUTHOR]

Background While controversy remains as to the relative benefit of operative (OM) versus non-operative management (NOM) of Achilles tendon (AT) ruptures (ATR), few studies have examined the effect on high impact maneuvers such as jumping and hopping. Hypothesis/Purpose The purpose of this study was to determine if functional performance including strength, jumping, and hopping outcomes differed between OM and NOM of acute ATR. The secondary objective was to assess the degree of association between AT morphology and performance outcomes. Study Design Retrospective cohort with a single prospective evaluation. Methods All patients were treated at an institutional secondary care center. Eligible participants (n=12 OM; 12 NOM) who were treated with OM or NOM of ATR within three weeks of injury were evaluated a minimum 20 months following ATR. AT length, thickness and gastrocnemius muscle thickness were assessed with B-mode ultrasound. Isokinetic plantar flexor strength, hop tests and countermovement and drop jumps were completed. Two-way ANOVAS were completed on all tests with unilateral values, independent t-tests were used for bilateral outcomes, and linear regressions were completed to assess the relationship between normalized AT length and performance. Results Affected limb AT was elongated and thickened (p<0.01), gastrocnemius was atrophied (p< 0.01) and angle-specific plantar flexor torque was reduced at 120°/s when measured at 20° plantar flexion (p = 0.028). Single leg drop vertical jump was higher in OM (p = 0.015) with no difference for hop and jump tests. AT length was related to plantar flexor torque but had no relationship with hopping performance. Conclusions Hop test performance was maintained despite plantarflexion weakness, gastrocnemius atrophy, and AT elongation. This may be the result of compensatory movement patterns. AT length holds limited explanatory power in plantar flexor strength, although this relationship should be evaluated further. Level of Evidence Level III [ABSTRACT FROM AUTHOR]

This study aimed to validate a 7-sensor inertial measurement unit system against optical motion capture to estimate bilateral lower-limb kinematics. Hip, knee, and ankle sagittal plane peak angles and range of motion (ROM) were compared during bodyweight squats and countermovement jumps in 18 participants. In the bodyweight squats, left peak hip flexion (intraclass correlation coefficient [ICC] =.51), knee extension (ICC =.68) and ankle plantar flexion (ICC =.55), and hip (ICC =.63) and knee (ICC =.52) ROM had moderate agreement, and right knee ROM had good agreement (ICC =.77). Relatively higher agreement was observed in the countermovement jumps compared to the bodyweight squats, moderate to good agreement in right peak knee flexion (ICC =.73), and right (ICC =.75) and left (ICC =.83) knee ROM. Moderate agreement was observed for right ankle plantar flexion (ICC =.63) and ROM (ICC =.51). Moderate agreement (ICC >.50) was observed in all variables in the left limb except hip extension, knee flexion, and dorsiflexion. In general, there was poor agreement for peak flexion angles, and at least moderate agreement for joint ROM. Future work will aim to optimize methodologies to increase usability and confidence in data interpretation by minimizing variance in system-based differences and may also benefit from expanding planes of movement. [ABSTRACT FROM AUTHOR]

Research indicates that increasing trunk flexion may optimize patellofemoral joint loading. However, this postural change could cause an excessive Achilles tendon force (ATF) and injury risk during movement. This study aimed to examine the effects of increasing trunk flexion during stair ascent on ATF, ankle biomechanics, and vertical ground reaction force in females. Twenty asymptomatic females (age: 23.4 [2.5] y; height: 1.6 [0.8] m; mass: 63.0 [12.2] kg) ascended stairs using their self-selected and flexed trunk postures. Compared with the self-selected trunk condition, decreases were observed for peak ATF (mean differences [MD] = 0.14 N/kg; 95% confidence interval [CI], 0.06 to 0.23; Cohen d = −1.2; P =.003), average rate of ATF development (MD = 0.25 N/kg/s; 95% CI, 0.07 to 0.43; Cohen d = −0.9; P =.010), ankle plantar flexion moment (MD = 0.08 N·m/kg; 95% CI, 0.03 to 0.13; Cohen d = −1.1; P =.005), and vertical ground reaction force (MD = 38.6 N/kg; 95% CI, 20.3 to 56.90; Cohen d = −1.8; P <.001). Increasing trunk flexion did not increase ATF. Instead, this postural change was associated with a decreased ATF rate and magnitude and may benefit individuals with painful Achilles tendinopathy. [ABSTRACT FROM AUTHOR]

Context: Cross-education (CE) refers to neuromuscular gains in the untrained limb upon contralateral limb training. To date, only laboratory-based exercise programs have demonstrated CE. Home-based exercise prescription eliciting CE could have greater clinical applicability. Objective: To determine the effect of an 8-week, home-based unilateral strength training intervention on isokinetic muscle strength, muscular excitation, and power in trained and untrained plantar flexors. Design: Randomized controlled trial. Methods: Thirty-four healthy participants were randomized to intervention (n = 20) or control (n = 14). The intervention group completed 3 sets of 12 repetitions of progressively loaded unilateral calf raises 3 days per week. Concentric and eccentric peak torque were measured using isokinetic dynamometry at 30°/s and 120°/s. Maximal electromyogram amplitude was simultaneously measured. Power was measured using a jump mat. All variables were measured at preintervention, midintervention, and postintervention. Results: Strength significantly increased bilaterally pre–post at both velocities concentrically and eccentrically in intervention group participants. Maximal electromyogram amplitude significantly increased pre–post bilaterally at both velocities in the medial gastrocnemii of the intervention group. Power significantly increased bilaterally pre–post in the intervention group, with a dose–response effect demonstrated in the untrained plantar flexors. The CE effects of strength, power, and electromyogram activation were 23.4%, 14.6%, and 25.3%, respectively. All control group values were unchanged pre–post. Conclusion: This study shows that a simple at-home unilateral plantar flexor exercise protocol induces significant increases in contralateral strength, muscular excitation, and power. These results suggest the applicability of CE in home rehabilitation programs aiming to restore or maintain neuromuscular function in inactive individuals or immobilized ankles. [ABSTRACT FROM AUTHOR]

Frontal plane ankle motion is important for balance in walking but is seldom controlled in robotic prostheses. This article describes the design, control and performance of a semi-active two-degree-of-freedom robotic prosthetic ankle. The mechanism uses a non-backdrivable wedge cam system based on rotating inclined planes, allowing actuation only during swing phases for low power, light weight and compactness. We present details of the mechanism and its kinematic and mechatronic control, and a benchtop investigation of the system’s speed and accuracy in ankle angle control. The two-axis ankle achieves angular reorientation movements spanning ±10 deg in any direction in less than 0.9 s. It achieves a plantarflexion/dorsiflexion error of 0.35 ± 0.27 deg and an inversion/eversion error of 0.29 ± 0.25 deg. Backdriven motion during walking tests is negligible. Strengths of the design include self-locking behavior for low power and simple kinematic control. Two-axis ankle angle control could enable applications such as balance augmentation, turning assistance, and wearable perturbation training.

Abstract Background The talocrural joint and the subtalar joint are the two major joints of the ankle-joint complex. The position and direction of the exosuit force line relative to these two joint axes can influence ankle motion. We aimed to understand the effects of different force-lines on ankle multidimensional motion. Methods In this article, three assistance force line schemes for ankle exosuits were proposed: perpendicular to the talocrural joint axis (PT), intersecting with the subtalar joint axis (IS), and parallel to the triceps surae (PTS). A theoretical model was proposed to calculate the exosuit’s assistance moment. Seven participants completed four experimental tests of ankle plantarflexion, including three passive motions assisted by the PT, PTS and IS schemes, and one active motion without exosuit assistance (Active). Results The simulation results demonstrated that all three exosuits were able to produce significant moments of ankle plantarflexion. Among these, the PT scheme exhibited the highest moments in all dimensions, followed by the PTS and IS schemes. The experimental findings confirmed the effectiveness of all three exosuit schemes in assisting ankle plantarflexion. Additionally, as the assistive force lines approached the subtalar joint, there was a decrease in ankle motion assisted by the exosuits in non-plantarflexion directions, along with a reduction in the average distance of ankle angle curves relative to active ankle motion. Furthermore, the linear correlation coefficients between inversion and plantarflexion, adduction and plantarflexion, and adduction and inversion gradually converged toward active ankle plantarflexion motion. Conclusions Our research indicates that the position of the exosuit force line to the subtalar joint has a significant impact on ankle inversion and adduction. Among all three schemes, the IS, which has the closest distance to the subtalar joint axes, has the greatest kinematic similarity to active ankle plantarflexion and might be a better choice for ankle assistance and rehabilitation.

It has been demonstrated that maximum isometric muscle moment can surpass maximum eccentric muscle moment at individually adjusted joint angles in men. However, no information about these muscle mechanics is available for women. To examine the maximum muscle moment hierarchy with equal conditions in women. Maximum voluntary concentric, eccentric, and isometric muscle moments of ankle, knee, and hip flexors and extensors as well as hip adductors and abductors were tested in eighteen young women. The sequence of muscle group testing was the same for all subjects, and the sequence of contraction types was randomized. All dynamic contractions were performed at 60∘/s. Peak moment angle of concentric contractions was applied for isometric moment testing. A repeated measures ANOVA with posthoc Bonferroni correction was used to compare means between contraction types. Differences in maximum moment mean values between the three contraction types were apparent for all muscle groups (p< 0.001). Concentric muscle moment was significantly the weakest contraction type. Eccentric contractions generated significantly higher moments than isometric contractions in dorsiflexion, plantarflexion, knee flexion, and hip adduction. Significant differences in maximum lower body muscle moments exist between concentric, eccentric, and isometric contractions in women. Compared to previous research for men there appears to be a sex-specific contraction type hierarchy with women exhibiting superior ability to generate higher eccentric muscle moment relative to other contraction types. These results should be considered when designing contractiontype specific intervention programs. [ABSTRACT FROM AUTHOR]

Background: Patients with knee osteoarthritis (KOA) are at high risk for falls, which is attributed to their impaired balance control. Identifying factors associated with balance control facilitates the development of precise KOA rehabilitation programs. This study was to investigate the correlations of balance control with proprioception, plantar tactile sensation (PTS), pain, joint range of motion (ROM), and strength among older adults with and without KOA, as well as the magnitudes and sequence of correlation of these factors to balance control. Methods: A total of 240 older adults with (n = 124, female: 84, age: 68.8 ± 4.0 years) and without (n = 116, female: 64, age: 67.9 ± 3.5 years) KOA were recruited and assigned to the KOA and control groups. Their proprioception, PTS, pain, ROM, and strength were measured. Pearson or Spearman correlations were used to test whether they were significantly related to their Berg Balance Scale (BBS), and factor analysis and multivariate linear regression were used to determine the degrees of correlation between each factor and the BBS. Results: Compared to the control group, the KOA group had lower BBS score, larger proprioception and PTS thresholds, smaller ROM, and less strength (p: 0.008, < 0.001–0.016, < 0.001–0.005, < 0.001–0.014, and < 0.001–0.002, respectively). In the KOA group, the BBS was weakly to moderately correlated with proprioception, PTS, pain, ROM, and strength (r: 0.332–0.501, 0.197–0.291, 0.340, 0.212–0.508, and 0.236–0.336, respectively). While in the control group, the BBS was correlated with proprioception and strength (r: 0.207–0.379, and 0.212–0.410). In the KOA group, BBS = 54.41+ (0.668*strength) - (0.579*PTS) - (1.141*proprioception) + (1.054* ROM) - (0.339*pain). While in the control group, BBS = 53.85+ (0.441*strength) - (0.677*proprioception). Conclusion: Worse proprioception and PTS, smaller ROM, and less strength were detected among older adults with KOA, and their proprioception, PTS, pain, ROM, and strength were all related to balance control. Proprioception had the strongest correlations, followed by ROM, strength, pain, and PTS. Precise KOA rehabilitation programs may be proposed following the sequence of improving the five factors. Key points: • Worse proprioception and plantar tactile sensation, smaller joint range of motion, and less strength were detected among older adults with knee osteoarthritis. • Among older adults with knee osteoarthritis, balance control was sequentially correlated with proprioception, joint range of motion, strength, pain, and plantar tactile sensation. • Precise knee osteoarthritis rehabilitation programs may be proposed following the sequence of improving proprioception, joint range of motion, strength, pain, and plantar tactile sensation. [ABSTRACT FROM AUTHOR]

Purpose: The aims of the study were to document the outcomes of percutaneous Achilles tenotomy (pAT) performed in older children with clubfoot, by assessing the clinical, functional and ultrasonographic evidence of Achilles tendon regeneration. Methods: A retrospective case series of older children with clubfoot treated between August 2011 and July 2020 was studied. Clinical assessment of ankle range of motion and calf strength, functional assessment of triceps surae muscle endurance by single leg heel-rise test, and ultrasonographic assessment of Achilles tendon echotexture and dimensions to assess tendon regeneration were performed. Results: Percutaneous Achilles tenotomy was performed on 31 children (48 clubfeet) at a mean age of 5.24 ± 2.14 years (1–10.2 years). At a mean follow-up of 4.86 ± 1.97 years, all children demonstrated normal calf strength with mean dorsiflexion range of 13.64° (0–25°) and mean plantarflexion range of 37.95° (10–40°). The heel-rise endurance test was completed by 27 children with mean 25.85 heel rises/minute (range 17–30) and mean height of heel rise of 6.29 cm (range 4–10 cm). Normal fibrillar tendinous echotexture with homogenous echogenicity was seen on ultrasonography in 41 feet (85.4%) with mean tendon width of 9.7 mm (3.3–16 mm) and thickness of 5.1 mm (1.8–15 mm), comparable with unaffected feet. Conclusions: Clinical, functional and ultrasonographic parameters unequivocally demonstrate complete regeneration of the Achilles tendon, when pAT is performed in older children with delayed-presenting idiopathic clubfoot treated using Ponseti principles. [ABSTRACT FROM AUTHOR]

Purpose: The Achilles tendon consists of three subtendons with the ability to slide relative to each other. As optimal intratendinous sliding is thought to reduce the overall stress in the tendon, alterations in sliding behavior could potentially play a role in the development of Achilles tendinopathy. The aims of this study were to investigate the difference in intratendinous sliding within the Achilles tendon during isometric contractions between asymptomatic controls and patients with Achilles tendinopathy and the effect of changing the horizontal foot position on intratendinous sliding in both groups. Methods: Twenty‐nine participants (13 Achilles tendinopathy and 16 controls) performed isometric plantarflexion contractions at 60% of their maximal voluntary contraction (MVC), in toes‐neutral, and at 30% MVC in toes‐neutral, toes‐in, and toes‐out positions during which ultrasound images were recorded. Intratendinous sliding was estimated as the superficial‐to‐middle and middle‐to‐deep relative displacement. Results: Patients with Achilles tendinopathy present lower intratendinous sliding than asymptomatic controls. Regarding the horizontal foot position in both groups, the toes‐out foot position resulted in increased sliding compared with both toes‐neutral and toes‐out foot position. Conclusion: We provided evidence that patients with Achilles tendinopathy show lower intratendinous sliding than asymptomatic controls. Since intratendinous sliding is a physiological feature of the Achilles tendon, the external foot position holds promise to increase sliding in patients with Achilles tendinopathy and promote healthy tendon behavior. Future research should investigate if implementing this external foot position in rehabilitation programs stimulates sliding within the Achilles tendon and improves clinical outcome. [ABSTRACT FROM AUTHOR]

The aim of our study was to compare the effects of two different plyometric training programs (targeting knee extensors or plantar flexors) on jump height and strength of leg muscles. Twenty‐nine male basketball players were assigned to the knee‐flexed (KF), knee‐extended (KE), or control groups. In addition to regular training, the KF group performed plyometric jumps (10 sets of 10 jumps, 3 sessions/week, 4 weeks) from 50 cm boxes with the knee flexed (90°–120°), whereas the KE group performed the jumps from 30 cm boxes with the knee much more extended (130°–170°). Jumping ability was evaluated with squat jumps (SJs), countermovement jumps (CMJs), and drop jumps from 20 cm (DJ20) and 40 cm (DJ40). Knee and ankle muscles were assessed during maximal isokinetic and isometric tests, and EMG activity was recorded from vastus lateralis and medial gastrocnemius. The KF group increased SJ (+10%, d = 0.86) and CMJ (+11%, d = 0.70) but decreased DJ40 height (−7%, d = −0.40). Conversely, the KE group increased DJ20 (+10%, d = 0.74) and DJ40 (+12%, d = 0.77) but decreased SJ height (−4%, d = −0.23). The reactivity index during DJs increased (+10% for DJ20, d = 0.47; +20% for DJ40, d = 0.91) for the KE group but decreased (−10%, d = −0.48) for the KF group during DJ40. Plantar flexor strength increased for the KE group (d = 0.72–1.00) but not for the KF group. Negative transfer across jumps is consistent with the principle of training specificity. Basketball players interested to perform fast rebounds in their training should avoid plyometric jumps with large knee flexions and long contact times. Highlights: Plyometric training specificity: different jump techniques (knee flexed vs. knee extended) elicited specific adaptations in jumping performance. Training with the knees flexed improved squat jump and countermovement jump height, whereas training with the knees extended augmented drop jump height.Negative transfer: the different jump techniques can have a negative influence on jump height and reactivity index. Drop jump height declined after knee‐flexed training, whereas squat jump height decreased after knee‐extended training.Plyometric training exercises should be aligned with sport‐specific movements to optimize performance. Basketball players who perform fast, powerful movements should avoid plyometric jumps with large knee flexions and long contact times. [ABSTRACT FROM AUTHOR]

Objective. The purpose of this study will be to determine the efficacy of low intensity lower extremity resistance training with and without blood flow restriction (BFR) on quadriceps muscle strength and thickness in veterans with advanced multiple sclerosis (MS). Methods. This will be an assessor-blinded, 2-group (1 to 1 allocation) randomized controlled trial targeting an enrollment of 58 participants with advanced MS as defined by Patient-Determined Disease Steps scale levels 4 to 7. Both groups will complete 10 weeks of twice weekly low-load resistance training (20%-30% of 1-repetition max) targeting knee and hip extension, knee flexion, and ankle plantarflexion. The intervention group will perform all training using BFR, with limb occlusion pressures between 60% and 80% of maximal limb occlusion pressure. Primary outcomes will be quadriceps muscle strength and thickness. Secondary outcomes will include knee flexion and ankle plantarflexion strength, functional mobility, physical activity, and patient-reported measures. All outcomes will be assessed at baseline before the intervention, immediately after the intervention, and at a 2-month follow-up assessment. The change between groups postintervention and after the 2-month follow-up will be reported for all outcomes. All analyses will assume a 2-sided test of hypothesis (α =.05). Impact. There is very little evidence for the efficacy of exercise interventions in people with MS who have advanced mobility disability. Resistance training with BFR may be an important approach for people with advanced MS who may not tolerate more conventional, moderate-to-high intensity resistance training. The results of this study will inform clinicians regarding exercise decisions for people with advanced MS and future investigations on the role of BFR in people with MS. [ABSTRACT FROM AUTHOR]

Background: Femoroacetabular impingement syndrome (FAIS) can cause hip pain and chondrolabral damage that may be managed non-operatively or surgically. Squatting motions require large degrees of hip flexion and underpin many daily and sporting tasks but may cause hip impingement and provoke pain. Differential effects of physiotherapist-led care and arthroscopy on biomechanics during squatting have not been examined previously. This study explored differences in 12-month changes in kinematics and moments during squatting between patients with FAIS treated with a physiotherapist-led intervention (Personalised Hip Therapy, PHT) and arthroscopy. Methods: A subsample (n = 36) of participants with FAIS enrolled in a multi-centre, pragmatic, two-arm superiority randomised controlled trial underwent three-dimensional motion analysis during squatting at baseline and 12-months following random allocation to PHT (n = 17) or arthroscopy (n = 19). Changes in time-series and peak trunk, pelvis, and hip biomechanics, and squat velocity and maximum depth were explored between treatment groups. Results: No significant differences in 12-month changes were detected between PHT and arthroscopy groups. Compared to baseline, the arthroscopy group squatted slower at follow-up (descent: mean difference −0.04 m∙s−1 (95%CI [−0.09 to 0.01]); ascent: −0.05 m∙s−1 [−0.11 to 0.01]%). No differences in squat depth were detected between or within groups. After adjusting for speed, trunk flexion was greater in both treatment groups at follow-up compared to baseline (descent: PHT 7.50° [−14.02 to −0.98]%; ascent: PHT 7.29° [−14.69 to 0.12]%, arthroscopy 16.32° [−32.95 to 0.30]%). Compared to baseline, both treatment groups exhibited reduced anterior pelvic tilt (descent: PHT 8.30° [0.21–16.39]%, arthroscopy −10.95° [−5.54 to 16.34]%; ascent: PHT −7.98° [−0.38 to 16.35]%, arthroscopy −10.82° [3.82–17.81]%), hip flexion (descent: PHT −11.86° [1.67–22.05]%, arthroscopy −16.78° [8.55–22.01]%; ascent: PHT −12.86° [1.30–24.42]%, arthroscopy −16.53° [6.72–26.35]%), and knee flexion (descent: PHT −6.62° [0.56– 12.67]%; ascent: PHT −8.24° [2.38–14.10]%, arthroscopy −8.00° [−0.02 to 16.03]%). Compared to baseline, the PHT group exhibited more plantarflexion during squat ascent at follow-up (−3.58° [−0.12 to 7.29]%). Compared to baseline, both groups exhibited lower external hip flexion moments at follow-up (descent: PHT −0.55 N∙m/BW∙HT[%] [0.05–1.05]%, arthroscopy −0.84 N∙m/BW∙HT[%] [0.06–1.61]%; ascent: PHT −0.464 N∙m/BW∙HT[%] [−0.002 to 0.93]%, arthroscopy −0.90 N∙m/BW∙HT[%] [0.13–1.67]%). Conclusion: Exploratory data suggest at 12-months follow-up, neither PHT or hip arthroscopy are superior at eliciting changes in trunk, pelvis, or lower-limb biomechanics. Both treatments may induce changes in kinematics and moments, however the implications of these changes are unknown. Trial registration details: Australia New Zealand Clinical Trials Registry reference: ACTRN12615001177549. Trial registered 2/11/2015. [ABSTRACT FROM AUTHOR]

We sought to investigate the lower-extremity biomechanics underlying increased gait velocity following high-cadence cycling. Ground reaction forces (GRF) and lower-extremity kinematics and kinetics were recorded as 15 healthy adults walked at a self-selected pace prior to and immediately following a 15 min bout of cycling at a cadence of 75 rotations per minute. Propulsive GRF and stance-phase peak dorsiflexion and knee extension angles increased, while peak plantarflexion and hip extension angles decreased. Swing-phase peak dorsiflexion, plantarflexion, knee flexion, and hip flexion angles increased, while peak knee extension angle decreased. Peak dorsiflexion, knee extension, and hip extension angular velocity also increased during swing. No changes in peak joint moments were observed; however, peak positive ankle, knee, and hip joint power generation increased following cycling. Completing high-cadence cycling improves gait velocity by increasing propulsive GRF; increasing joint angular velocity during the swing phase of gait for the ankle, knee, and hip; and increasing positive power production by the ankle, knee, and hip during the stance phase. Increased gait velocity post cycling exercise did not increase lower-extremity joint moments. Cycling may be a viable exercise-based modality for increasing gait velocity, especially in populations where gait ability or joint loading is of particular concern. [ABSTRACT FROM AUTHOR]

Frontal plane ankle motion is important for balance in walking but is seldom controlled in robotic prostheses. This article describes the design, control and performance of a semi-active two-degree-of-freedom robotic prosthetic ankle. The mechanism uses a non-backdrivable wedge cam system based on rotating inclined planes, allowing actuation only during swing phases for low power, light weight and compactness. We present details of the mechanism and its kinematic and mechatronic control, and a benchtop investigation of the system's speed and accuracy in ankle angle control. The two-axis ankle achieves angular reorientation movements spanning ±10 deg in any direction in less than 0.9 s. It achieves a plantarflexion/dorsiflexion error of 0.35 ± 0.27 deg and an inversion/eversion error of 0.29 ± 0.25 deg. Backdriven motion during walking tests is negligible. Strengths of the design include self-locking behavior for low power and simple kinematic control. Two-axis ankle angle control could enable applications such as balance augmentation, turning assistance, and wearable perturbation training. [ABSTRACT FROM AUTHOR]

Background: The talocrural joint and the subtalar joint are the two major joints of the ankle-joint complex. The position and direction of the exosuit force line relative to these two joint axes can influence ankle motion. We aimed to understand the effects of different force-lines on ankle multidimensional motion. Methods: In this article, three assistance force line schemes for ankle exosuits were proposed: perpendicular to the talocrural joint axis (PT), intersecting with the subtalar joint axis (IS), and parallel to the triceps surae (PTS). A theoretical model was proposed to calculate the exosuit’s assistance moment. Seven participants completed four experimental tests of ankle plantarflexion, including three passive motions assisted by the PT, PTS and IS schemes, and one active motion without exosuit assistance (Active). Results: The simulation results demonstrated that all three exosuits were able to produce significant moments of ankle plantarflexion. Among these, the PT scheme exhibited the highest moments in all dimensions, followed by the PTS and IS schemes. The experimental findings confirmed the effectiveness of all three exosuit schemes in assisting ankle plantarflexion. Additionally, as the assistive force lines approached the subtalar joint, there was a decrease in ankle motion assisted by the exosuits in non-plantarflexion directions, along with a reduction in the average distance of ankle angle curves relative to active ankle motion. Furthermore, the linear correlation coefficients between inversion and plantarflexion, adduction and plantarflexion, and adduction and inversion gradually converged toward active ankle plantarflexion motion. Conclusions: Our research indicates that the position of the exosuit force line to the subtalar joint has a significant impact on ankle inversion and adduction. Among all three schemes, the IS, which has the closest distance to the subtalar joint axes, has the greatest kinematic similarity to active ankle plantarflexion and might be a better choice for ankle assistance and rehabilitation. [ABSTRACT FROM AUTHOR]

Individuals with anterior cruciate ligament reconstruction (ACLR) utilise different landing biomechanics between limbs, but previous analyses have not considered the continuous or simultaneous joint motion that occurs during landing and propulsion. The purpose of this study was to compare sagittal plane ankle/knee and knee/hip coordination patterns as well as ankle, knee, and hip angles and moments and vertical ground reaction force (vGRF) between the ACLR and uninjured limbs during landing and propulsion. Fifteen females and thirteen males performed a drop vertical jump from a 30 cm box placed half their height from force platforms. Coordination was compared using a modified vector coding technique and binning analysis. Kinematics and kinetics were time normalised for waveform analyses. Coordination was not different between limbs. The ACLR limb had smaller dorsiflexion angles from 11 to 16% of landing and 24 to 75% of landing and propulsion, knee flexion moments from 5 to 15% of landing, 20 to 31% of landing, and 35 to 91% of landing and propulsion, and vGRF from 92 to 94% of propulsion compared with the uninjured limb. The ACLR limb exhibited smaller dorsiflexion angles to potentially reduce the knee joint moment arm and mitigate the eccentric and concentric demands on the ACLR knee during landing and propulsion, respectively. [ABSTRACT FROM AUTHOR]

Background: The hallux dorsiflexion resistance test is a frequently employed clinical maneuver for assessing the initiation of the windlass mechanism This maneuver involves dorsiflexion of the phalanx of the hallux, thereby evaluating plantarflexion of the first metatarsal, elevation of the medial longitudinal arch, and supination of the rearfoot. The windlass mechanism plays a crucial role in gait, and orthopedic devices, such as a kinetic wedge, which aims to facilitate its activation by increasing the hallux dorsiflexion. Although it is believed that facilitating the windlass mechanism with the kinetic wedge should be directly correlated with a decrease in hallux dorsiflexion resistance, its effects have yet to be characterized. Thus, this study aimed to determine the influence of a kinetic wedge on hallux dorsiflexion resistance in asymptomatic individuals. Methods: The sample comprised thirty participants (14 women and 16 men). A digital force gauge measured the force required to perform the hallux dorsiflexion resistance test during two conditions: barefoot and with a kinetic wedge. The Wilcoxon signed-rank test was used to compare the hallux dorsiflexion resistance between conditions. Results: A statistically significant reduction in force (10.54 ± 3.16N vs. 19.62 ± 5.18N, p < 0.001) was observed when using the kinetic wedge compared to the barefoot condition during the hallux dorsiflexion resistance test. Conclusion: The use of a kinetic wedge reduces the required force for performing the passive hallux dorsiflexion resistance test in asymptomatic individuals. Future studies should determine to what extent the kinetic wedge can attenuate the required force to dorsiflex the hallux in individuals with musculoskeletal disorders such as plantar fasciopathy and functional hallux limitus. [ABSTRACT FROM AUTHOR]

Background: Talar fractures often require osteotomy during surgery to achieve reduction and screw fixation of the fractured fragments due to limited visualization and operating space of the talar articular surface. The objective of this study was to evaluate the horizontal approach to the medial malleolus facet by maximizing exposure through dorsiflexion and plantarflexion positions. Methods: In dorsiflexion, plantarflexion, and functional foot positions, we respectively obtained the anterior and posterior edge lines of the projection of the medial malleolus on the medial malleolar facet. The talar model from Mimics was imported into Geomagic software for image refinement. Then Solidworks software was used to segment the medial surface of the talus and extend the edge lines from the three positions to project them onto the "semicircular" base for 2D projection. The exposed area in different positions, the percentage of total area it represents, and the anatomic location of the insertion point at the groove between the anteroposternal protrusions of the medial malleolus were calculated. Results: The mean total area of the "semicircular" region on the medial malleolus surface of the talus was 542.10 ± 80.05 mm2. In the functional position, the exposed mean area of the medial malleolar facet around the medial malleolus both anteriorly and posteriorly was 141.22 ± 24.34 mm2, 167.58 ± 22.36mm2, respectively. In dorsiflexion, the mean area of the posterior aspect of the medial malleolar facet was 366.28 ± 48.12 mm2. In plantarflexion, the mean of the anterior aspect of the medial malleolar facet was 222.70 ± 35.32 mm2. The mean overlap area of unexposed area in both dorsiflexion and plantarflexion was 23.32 ± 5.94 mm2. The mean percentage of the increased exposure area in dorsiflexion and plantarflexion were 36.71 ± 3.25% and 15.13 ± 2.83%. The mean distance from the insertion point to the top of the talar dome was 10.69 ± 1.24 mm, to the medial malleolus facet border of the talar trochlea was 5.61 ± 0.96 mm, and to the tuberosity of the posterior tibiotalar portion of the deltoid ligament complex was 4.53 ± 0.64 mm. Conclusions: Within the 3D model, we measured the exposed area of the medial malleolus facet in different positions and the anatomic location of the insertion point at the medial malleolus groove. When the foot is in plantarflexion or dorsiflexion, a sufficiently large area and operating space can be exposed during surgery. The data regarding the exposed visualization area and virtual screws need to be combined with clinical experience for safer reduction and fixation of fracture fragments. Further validation of its intraoperative feasibility will require additional clinical research. [ABSTRACT FROM AUTHOR]

Achilles tendon rupture is a common sports‐related injury which can carry significant morbidity to patients. Ultrasound remains the workhorse of imaging as it can confirm and localise the extent of Achilles tendon injury. The sonographic anatomy, both normal and ruptured sonographic appearances, as well as sonographic technique must be appreciated to accurately image and report findings, critical to patient management. Particular attention should be applied to the measurement of the diastasis between acutely ruptured tendon ends as this information can assist with informing the decision of conservative vs. operative management. Further work is necessary to standardise the measurement technique including correlating the degree of plantarflexion of the foot with the sonographic tendon gap measures. [ABSTRACT FROM AUTHOR]

Background: Historically, kinematic measures have been compared across injured and non-injured groups of runners, failing to take into account variability in kinematic patterns that exist independent of injury, and resulting in false positives. Research led by gait patterns and not pre-defined injury status is called for, to better understand running-related injury (RRI) aetiology and within- and between-group variability. Objectives: Synthesise evidence for the existence of distinct kinematic sub-groups across a population of injured and healthy runners and assess between-group variability in kinematics, demographics and injury incidence. Data Sources: Electronic database search: PubMed, Web of Science, Cochrane Central Register of Controlled Trials (Wiley), Embase, OVID, Scopus. Eligibility Criteria: Original, peer-reviewed, research articles, published from database start to August 2022 and limited to English language were searched for quantitative and mixed-methods full-text studies that clustered injured runners according to kinematic variables. Results: Five studies (n = 690) were included in the review. All studies detected the presence of distinct kinematic sub-groups of runners through cluster analysis. Sub-groups were defined by multiple differences in hip, knee and foot kinematics. Sex, step rate and running speed also varied significantly between groups. Random injury dispersal across sub-groups suggests no strong evidence for an association between kinematic sub-groups and injury type or location. Conclusion: Sub-groups containing homogeneous gait patterns exist across healthy and injured populations of runners. It is likely that a single injury may be represented by multiple movement patterns, and therefore kinematics may not predict injury risk. Research to better understand the underlying causes of kinematic variability, and their associations with RRI, is warranted. [ABSTRACT FROM AUTHOR]

The primary objective of this study was to investigate the relationship between metatarsophalangeal joint (MTPj) flexion torque and sprint acceleration, cutting and jumping performance, and kinetics. A secondary aim was to explore this relationship when MTP flexion strength was associated with other foot and lower limb neuromuscular outputs. After an initial MTPj flexion torque assessment using a custom-built dynamometer, 52 high-level athletes performed the following tasks on a force platform system: maximal sprint acceleration, 90-degree cutting, vertical and horizontal jumps, and foot-ankle hops. Their foot posture, foot passive stiffness and foot-ankle reactive strength were assessed using the Foot Posture Index, the Arch Height Index Measurement System and the Foot-Ankle Rebound Jump Test. Ankle plantarflexion and knee extension isometric torque were assessed using an isokinetic dynamometer. During maximal speed sprinting, multiple linear regressions suggested a major contribution of MTPj flexion torque, foot passive stiffness and foot-ankle reactive strength to explain 28% and 35% of the total variance in the effective vertical impulse and contact time. Ankle plantarflexor and quadriceps isometric torques were aggregately contributors of acceleration performance and separate contributors of cutting and jumping performance. In conclusion, MTPj flexion torque was more strongly associated with sprinting performance kinetics especially at high-speed. [ABSTRACT FROM AUTHOR]

Background Chronic ankle instability is a common sports injury that often presents with increased plantarflexion and restricted dorsiflexion. The cumulative effect of peripheral injuries may induce neuroplasticity in the central nervous system. However, the relationship between dorsiflexion or plantarflexion and the central nervous system in patients with chronic ankle instability remains unknown. Questions/purposes (1) Is there a difference in region and voxel (volume pixel) of cortical activation during plantar-flexion and dorsiflexion between patients with chronic ankle instability and a control group with normal ankle function? (2) Is there a correlation between activation of sensorimotor-related brain regions and three clinical measurement scales of ankle function and disease severity in patients with chronic ankle instability? Methods Between December 2020 and May 2022, we treated 400 patients who had chronic ankle instability. Ten percent (40 patients; mean6standard deviation age 29 ± 7 years; 17 male patients) were randomly selected to participate in this study.We recruited 42 volunteers with normal ankle function (mean age 28 ± 5 years; 21 male participants) matched by age and education level. A total of 2.5% (1 of 40) of patients with bilateral chronic ankle instability and 30% (12 of 40) with left-sided chronic ankle injury did not meet our inclusion criteria and were excluded from the study. The control group underwent MRI with good image quality. Finally, 27 patients with chronic ankle instability (mean age 26 6 5 years; 10 male patients) and 42 participants with normal ankle function were enrolled. Ankle function and disease severity were assessed using three clinical scales: the Cumberland Ankle Instability Tool, Karlsson-Peterson Ankle Function Score, and the American Orthopedic Foot and Ankle Society Score. A uniplanar and nonweightbearing ankle dorsiflexion-plantarflexion paradigm (a recognized model or pattern) was performed using a short-block design during the functional MRI scan. This experimental design included a series of on-off periods consisting of movement and a rest period. From 15° of plantarflexion to 15° of dorsiflexion, the manipulator allowed 30° of ankle rotation. The cerebral excitability patterns between patients with chronic ankle instability and controls were analyzed using t-tests. We retained voxels with p values less than 0.05 in a voxel-level family-wise error correction. Clusters with voxel numbers greater than 10 were retained. The Cohen d coefficient was used to calculate between-group effect sizes. Spearman analysis was performed to explore the correlation between activation regions and the three clinical assessment scales. Results In the patient group, cortical activation was greater during plantarflexion than during dorsiflexion, which was different from that in the control group. The between-group comparison showed that patients with chronic ankle instability had reduced activation in the ipsilateral precuneus (cluster size = 35 voxels [95% CI -0.23 to 0.07]; p < 0.001) during dorsiflexion, whereas during plantarflexion, chronic ankle instability caused increased activation in the ipsilateral superior temporal gyrus (cluster size = 90 voxels [95% CI -0.73 to -0.13]; p < 0.001), precuneus (cluster size = 18 voxels [95% CI -0.56 to -0.19]; p < 0.001), supplementary motor area (cluster size = 57 voxels [95% CI -0.31 to 0.00]; p < 0.001), superior frontal gyrus (cluster size = 43 voxels [95% CI -0.82 to -0.29]; p < 0.001), medial part of the superior frontal gyrus (cluster size = 39 voxels [95% CI 0.41 to 0.78]; p < 0.001), and contralateral postcentral gyrus (cluster size = 100 voxels [95% CI -0.32 to 0.02]; p < 0.001). Patients with chronic ankle instability showed a large effect size compared with controls (Cohen d > 0.8). During plantarflexion, the number of activated voxels in the supplementary motor area had a modest, positive correlation with the Karlsson-Peterson Ankle Function Score (r = 0.52; p = 0.01), and the number of activated voxels in the primary motor cortex (M1) and primary sensory cortex (S1) had a weak, positive correlation with the American Orthopedic Foot and Ankle Society Score in patients with chronic ankle instability (M1: r = 0.45; p = 0.02, S1: r = 0.49; p = 0.01). Conclusion Compared with volunteers with normal ankle function, patients with chronic ankle instability had increased cortical activation during plantarflexion and decreased cortical activation during dorsiflexion. We analyzed the central neural mechanisms of chronic ankle instability in patients with sports injuries and provided a theoretical basis for the development of new central and peripheral interventions in the future. Clinical Relevance Because there was a positive correlation between the neural activity in sensorimotor-related regions during plantarflexion and clinical severity, clinicians might one day be able to help patients who have chronic ankle instability with neuromuscular rehabilitation by applying electrical stimulation to specific targets (such as S1M1 and the supplementary motor area) or by increasing activation of sensorimotor neurons through ankle movement. [ABSTRACT FROM AUTHOR]

This article presents the findings of a study on chronic ankle instability and its impact on the nervous system. Using functional MRI, the study examined the differences in brain activity during specific ankle movements in individuals with chronic ankle instability. The results suggest that ankle ligament injuries not only affect the physical aspects of the joint but also have neurological implications. The article emphasizes the need for further research to better understand the relationship between anatomy, muscle function, brain function, and joint mechanics in chronic ankle instability. It also highlights the importance of personalized screening programs, injury prevention protocols, rehabilitation techniques, and surgical treatments based on individual factors. Additionally, the document provides a list of references that cover various subjects related to ankle injuries, ankle sprains, and other foot and ankle topics, which can be useful for library patrons conducting research in this area. [Extracted from the article]

Background: Although intraoperative ankle motion serves as a foundational reference for anticipated motion after surgery and guides the addition of procedures to enhance ankle motion in total ankle arthroplasty (TAA), the relationship between intraoperative and postoperative ankle motion remains unclear. This study aimed to investigate the discrepancy between intraoperative and postoperative ankle range of motion (ROM) following TAAs using the anterior-approach, fixed-bearing systems. Methods: This study retrospectively reviewed 67 patients (67 ankles) who underwent primary TAA at a single institution. Three different types of anterior-approach, fixed-bearing TAA systems were included. Intraoperative fluoroscopy was used to document the maximal dorsiflexion and plantar flexion at the end of the case. Standardized weightbearing maximum dorsiflexion and plantar flexion sagittal radiographs were obtained pre- and postoperatively, following a previously described method. The motion between 3 different time points (preoperative, intraoperative, and postoperative [mean 11.4 months]) was compared using pairwise t tests, and their differences were quantified. Results: The mean total tibiotalar ROM was 38.1 degrees (SD 7.8) intraoperatively, and the postoperative total tibiotalar ROM was 24.2 degrees (SD 9.7) (P <.001), indicating that a mean of 65.3% (SD 26.7) of the intraoperative motion was maintained postoperatively. Intraoperative dorsiflexion (mean 11.6 [SD 4.5] degrees) showed no evidence of difference from postoperative dorsiflexion (mean 11.4 [SD 5.8] degrees, P >.99), indicating that a median of 95.6% (interquartile range: 66.2-112) of the intraoperative maximum dorsiflexion was maintained postoperatively. However, there was a significant difference between intraoperative plantarflexion (mean 26.4 [SD 6.3]) and postoperative plantarflexion (12.8 [SD 6.9] degrees, P <.001), indicating a mean 50.6% (SD 29.6) of intraoperative motion maintained in the postoperative assessment. There was an improvement of 2.5 degrees in the total tibiotalar ROM following TAA with statistical significance (P <.043). Conclusion: This study revealed a significant difference between intraoperative ankle ROM and ankle ROM approximately 1 year after anterior-approach, fixed-bearing TAA, mainly due to plantarflexion motion restriction. Minimal difference in dorsiflexion suggests the importance of achieving the desired postoperative dorsiflexion motion during the surgery using the best possible adjunct procedures. Level of Evidence: Level IV, case series. [ABSTRACT FROM AUTHOR]