BackgroundAlthough high serve velocity is recognized as a decisive factor in women's tennis, the specific in-match kinematic variations that distinguish top-ranked players from lower-ranked competitors remain under-investigated.MethodsThe videos of the first serve were collected at competition venues from seven top-ranked players (ranked within the top 40 as of September 2019) and ten lower-ranked players (ranked outside the top 100). Joint angles were calculated using three-dimensional projection angle method based on the kinematic data obtained from FM3DMotion software. Independent-samples t-test and Mann–Whitney U test were employed to compare the kinematic differences between the two groups.ResultsBall velocity, elbow angle at maximum knee flexion, elbow angle at the racket's lowest position, and peak elbow angular velocity during the cocking phase were greater in top-ranked players (p < 0.05). The center of mass to racket side foot distance, shoulder external rotation angle at maximum knee flexion, occurrence time of hip peak linear velocity, and ranges of trunk flexion/extension and lateral flexion during the acceleration phase were greater in lower-ranked players (p < 0.05).ConclusionsKinematics such as an elevated upper arm and open elbow at MKF, a rapid elbow flexion during cocking phase, and dominant trunk rotation are characteristic of elite players. These patterns may serve as potential technical targets for developing players aiming to optimize serve velocity.

Although fatigue is widely recognized as a risk factor for hamstring strain injuries, the mechanisms by which fatigue influences these injuries remain unclear. It is also uncertain whether fatigue differentially affects the risk factors for hamstring strain between lower limbs. Nineteen male track-and-field athletes underwent a fatigue intervention, with optimal muscle length assessed pre- and post-fatigue. Key biomechanical parameters during sprinting were also analyzed before and after fatigue. Post-fatigue, the non-dominant limb showed significant reductions in optimal lengths across all three biarticular hamstring muscles (p < 0.01; Cohen’s d = 0.95–1.07), with greater changes than the dominant limb (p < 0.05; η_p^2 = 0.16–0.24). No significant differences were observed in maximal hip–knee angles, peak muscle lengths, or the timing of peak muscle strain (p > 0.05). However, the non-dominant limb exhibited increased peak strain in the long head of the biceps femoris and semimembranosus (p < 0.05; Cohen’s d = 0.46–0.52), but not in the semitendinosus (p = 0.06; Cohen’s d = 0.90). No significant inter-limb differences were observed in the strain changes of the hamstring biarticular muscles (p > 0.05). Fatigue was not associated with changes in sprint-phase peak lengths of the non-dominant biarticular hamstring muscles; however, it was accompanied by a reduction in optimal length, which may have increased peak strain. Clinically, monitoring fatigue-related changes in hamstring functional properties and addressing potential inter-limb asymmetries may be relevant for injury prevention and rehabilitation. The same fatigue protocol was not associated with increased peak strain on the dominant side, indicating a potential limb-specific susceptibility to fatigue-related strain increases.

INTRODUCTION:During a half-squat parachute landing, foot-strike pattern influences joint kinematics and injury risk. This study compared forefoot and full-foot landing techniques to determine their effects on joint biomechanics, impact forces, and landing stability. METHODS:A total of 17 male paratroopers performed both landing conditions. Lower-limb kinematics, ground reaction forces, and surface electromyography were synchronously recorded using infrared motion capture, a force platform, and wireless electromyography. Paired-sample t-tests or Wilcoxon signed-rank tests were applied (α = 0.05). RESULTS:Forefoot landing produced greater knee (96.8 ± 12.2° vs. 89.3 ± 11.2°) and ankle range of motion (12.7 ± 3.8° vs. 10.8 ± 3.1°), higher peak knee (1206.4 ± 108.7 ° · s-1 vs. 1147.8 ± 88.8 ° · s-1) and ankle flexion angular velocity (223.5 ± 60.1 ° · s-1 vs. 156.5 ± 42.5 ° · s-1), and a longer braking phase (265.0 ± 29.4 ms vs. 246.5 ± 24.7 ms). It also reduced peak vertical ground reaction forces, loading rate, and dynamic postural stability index, and increased time to peak ground reaction forces. During preactivation, electromyography amplitudes were higher for the biceps femoris (0.097 ± 0.066 vs. 0.081 ± 0.071), lateral gastrocnemius (0.304 ± 0.251 vs. 0.130 ± 0.070), and medial gastrocnemius (0.203 ± 0.144 vs. 0.111 ± 0.105). During the braking phase, amplitudes were higher in the rectus femoris, biceps femoris, semitendinosus, lateral gastrocnemius, and medial gastrocnemius. DISCUSSION:Forefoot landing enhances joint motion, muscle activation, impact attenuation, and dynamic stability during half-squat parachute landing. It may therefore represent a safer landing strategy. Findings should be interpreted cautiously due to the small, all-male sample. Ye Q, Chen H, Huang B, Wan X, Wang G. Landing technique effects on lower-limb biomechanics during half-squat parachute landing. Aerosp Med Hum Perform. 2026; 97(6):435-442.

Weightlifting movements have been shown to provide a superior training stimulus for force and power development. Among these, Weightlifting pulling derivatives (WPDs) without the catch phase may generate superior kinetic stimulation compared to the full weightlifting movements. Previous studies have confirmed that the starting position significantly affects the peak vertical ground reaction forces (Fz), peak rate of force development (RFD), and peak power of the weightlifting derivatives with the catch phase. However, the influence of starting position on WPDs is still unclear. Therefore, this study aims to compare the kinetic performance differences of WPDs with different starting positions to optimize training programs. Eighteen men (age: 21.44±1.76 years; height: 1.78±0.06 m; mass: 75.56±6.61 kg; power clean 1RM: 104.03±11.41 kg) were recruited. This study employed a within-subject design, whereby peak Fz, peak RFD, and peak power were determined during the clean pull (CP), clean pull from the knee (CPK), and midthigh clean pull (MCP). Participants were tested in a balanced sequence using a standardized load (60% of power clean 1RM). All lifts were performed with the subjects standing on a force plate (Kunwei, KWF6040-10K), sampling at 1,000 Hz. A repeated-measures ANOVA was conducted to compare the three variants, a significance level of 0.05. Bonferroni-corrected post-hoc tests identified significant mean differences. Result: Significant differences were among the WPDs with different starting positions for peak Fz (p < 0.001), peak instantaneous RFD (p < 0.001), and peak power (p < 0.001). Subsequent post-hoc tests indicated that: The MCP had significantly higher peak Fz than CPK (p < 0.001), which in turn had higher values than the CP (p < 0.001). The MCP had significantly higher peak RFD than the CP (p < 0.001), which in turn had higher values than the CPK (p < 0.001). The CPK significantly higher peak power than the MCP (p = 0.010), which was higher than the CP (p = 0.004). This study demonstrates that when the objective is to maximize force development, the midthigh-starting position for WPD is optimal. When the goal shifts to maximizing power development, unlike the clean variations, where the mid-thigh-starting position is the optimal choice, the knee-starting position for WPD is superior. This difference may be attributed to the initial velocity provided by the transition phase and the increased bar speed achievable with WPD. Since WPDs with different starting positions commonly use different loads in practice, future research should consider this aspect.

ObjectiveAfter stroke, patients often exhibit abnormal gait and cortical activation patterns during obstacle crossing, which heightens their risk of falls. This study aimed to examine the effects of Motor dual-task gait training (MDTG) and cognitive dual-task gait training (CDTG) on gait and cortical activation during obstacle crossing in stroke patients, to clarify their differential effects and underlying neural mechanisms.Methods35 stroke patients were recruited and randomly assigned to either the MDTG group (n = 17) or the CDTG group (n = 18), and were assigned to receive the corresponding intervention training. Participants in both groups underwent a 4 week training program, consisting of three sessions per week. Spatio-temporal parameters, lower limb joint angles and moments, and changes in oxyhemoglobin concentrations (ΔHbO2) were assessed in patients during obstacle crossing both pre- and post-training.ResultsFollowing training, both groups demonstrated significant improvements in stride length, step length, step width, gait speed, toe-obstacle clearance of the leading and trailing limb, toe-obstacle distance of the trailing limb, anteroposterior and mediolateral COM displacement, mediolateral COM mean velocity, anteroposterior COM-COP distance, hip flexion angle of the leading limb, knee flexion angle of the trailing limb, and peak hip flexion moment of the trailing limb (P < 0.05). Concurrently, following the training, ΔHbO2 in the bilateral prefrontal cortex was significantly reduced during obstacle crossing (P < 0.05). However, no significant differences were observed between the two groups for any parameters (P>0.05).ConclusionA 4-week program of either MDTG or CDTG effectively improved postural stability, enhanced control of the swing limb and COM, and increased efficiency in cortical resource utilization during obstacle crossing in stroke patients. However, no differences in these effects were observed between the two training modalities.Clinical Trial Registrationhttps://www.chictr.org.cn/showproj.html?proj=200755, identifier ChiCTR2300077304.

Background This study investigated whether differences in ice hockey helmet protection performance at varying impact velocities influence head injury risk. Methods Linear acceleration data were recorded during drop tests on 24 ice hockey helmets by using a uniaxial accelerometer in a collision test machine under low- and ambient-temperature environments for sequential low-, medium-, and high-velocity impacts. Head injury criterion (HIC), seasonal injury risk (SIR) under different impact velocities, and total seasonal injury risk (TSIR) were calculated for each helmet location. Results In both temperature environments, the back, front, and side locations produced higher TSIR than the top. Under low-velocity impacts, the side location produced higher SIR and HIC than the back and front. Under medium- and high-velocity impacts, the side location produced lower SIR than the back and front, or showed no difference compared to the back. Except for comparisons between the side and back/front under low-velocity impacts, SIR and HIC differences across locations were inconsistent or nonsignificant. Conclusion These findings suggest that under low-velocity impacts, the higher HIC at the side location may be a key factor influencing head injury risk. To enhance helmet protective performance, optimizing energy absorption at the side location during low-velocity impacts is recommended.

Declined lower-limb coordination is one of the main factors to the increased risk of falls in patients with stroke. Dual-task gait training has been shown to be effective in improving lower-limb coordination during single-task walking. However, its efficacy in enhancing coordination during dual-task gait remains unclear. Therefore, this study aims to investigate the effects of cognitive dual-task gait training (CDTG) and motor dual-task gait training (MDTG) on lower-limb coordination during dual-task gait in patients with subacute stroke. Thirty-five patients with subacute stroke were randomly assigned to the MDTG group (n = 17) or CDTG group (n = 18), and received a 4-week intervention. An infrared high-speed motion capture system was used to collect trajectory data of surface markers during dual-task gait tests. Lower-limb coordination was assessed using the mean continuous relative phase (MCRP) and its variability (MCRPV) between joints. A mixed-design ANOVA was used to analyze training effects. After training, during cognitive dual-task gait, both groups showed increased MCRP between the unaffected hip and knee during the affected-side stance period (P = 0.002). In the MDTG group, bilateral hip MCRP increased (P = 0.026), while in the CDTG group, bilateral ankle MCRP increased (P = 0.031). During motor dual-task gait, the CDTG group showed increased MCRP between the affected hip and knee in the stance period (P = 0.017) and decreased MCRPV between the unaffected hip and knee in the swing period (P = 0.035). Four weeks of MDTG can promote out-of-phase coordination between the unaffected hip and knee joints, as well as the bilateral hip joints, during cognitive dual-task gait in patients with subacute stroke. CDTG improves out-of-phase coordination between the unaffected hip and knee joints, and the bilateral ankle joints, during cognitive dual-task gait. It also facilitates out-of-phase coordination of the affected hip and knee joints and enhances the coordination stability of the unaffected side during motor dual-task gait. These findings support task-specific dual-task gait training as a targeted approach to improve coordination and reduce fall risk in subacute stroke rehabilitation. The trial was registered on 03/11/2023 at ChiCTR, under the registration number ChiCTR2300077304.

This study investigated the acute effects of combat boots and minimalist shoes on Achilles tendon (AT) loading during running under different load carriage magnitudes in soldiers. Eighteen rearfoot-strike soldiers performed running tests under three load conditions (0, 10, and 20 kg) while wearing either minimalist shoes or combat boots. The coordinates of the body landmarks and ground reaction force data were simultaneously collected using the infrared high-speed motion capture system and force plates. The musculoskeletal model was established to calculate AT biomechanical parameters. Results showed that AT force impulse and stance duration increased with higher load magnitudes. Load carriage increased AT force during the midstance phase but decreased it during the early stance phase. Compared with combat boots, running in minimalist shoes decreased AT force during the terminal stance phase and shortened stance duration but increased AT force during the early stance phase. However, no main effect of footwear on AT force impulse was found. Additionally, no interaction effect between footwear and load carriage magnitude was observed for any biomechanical parameter. These findings suggest that minimalist shoes provide limited acute benefits in reducing cumulative AT loading and therefore are not recommended for soldiers during load carriage.

During obstacle crossing, both obstacle height and leading limb choice may influence gait characteristics and fall risk in people post stroke. This study compared their gait characteristics when leading with different limbs to cross obstacles of varying heights, aiming to inform targeted rehabilitation. Twenty people post stroke were recruited. A motion capture system and two force plates were used to record marker positions and ground reaction forces as participants crossed the 10% and 20% leg-length obstacle, leading with either the paretic or non-paretic limb. The results demonstrated that, regardless of the leading limb, participants exhibited significantly lower gait velocity, COM velocity, and COM-COP distance when crossing the 20% versus 10% leg-length obstacle (P < 0.05). The obstacle-heel distance of the leading limb was also significantly greater for the higher obstacle (P < 0.05). At all tested obstacle heights, when participants led with their paretic limb, obstacle-heel distance of the leading limb, toe- obstacle clearance of the trailing limb, mediolateral COM-COP distance (when the leading limb's toe was above the obstacle), and anteroposterior COM velocity (when the trailing limb's toe was above the obstacle, T2) were significantly greater compared to leading with their non-paretic limb (P < 0.05). However, toe clearance of the leading limb and mediolateral COM-COP distance (when T2) were significantly lower (P < 0.05). These results suggest that people post stroke adopt a conservative crossing strategy to maintain stability when crossing 20% leg-length obstacle. Regardless of the leading limb, they exhibited impaired spatial regulation of the paretic foot relative to the obstacle and reduced paretic stance stability.

Reduced lower-limb coordination is considered one of the reasons for the increased risk of falls during walking in patients with stroke. However, it remains unclear whether lower-limb coordination during single- and dual-task walking affects fall risk in this population. Therefore, this study aimed to develop regression models based on the mean continuous relative phase (MCRP) and its variability (MCRPV) under different walking conditions to explore the relationship between lower-limb coordination and fall risk. Forty patients with stroke were enrolled and followed up for one year after completing single-task walking, cognitive dual-task walking, and motor dual-task walking tests. Participants were divided into fallers and non-fallers according to whether a fall occurred during the follow-up. Indicators showing significant between-group differences without collinearity were used as predictors in the regression models. The results showed that increased MCRPV between the unaffected hip and knee joints during the affected-side stance phase in single-task walking, increased MCRPV between the affected knee and ankle joints during the affected-side swing phase in cognitive dual-task walking, and increased MCRP between the unaffected hip and knee joints during the affected-side swing phase in motor dual-task walking were all associated with a higher risk of falling in patients with stroke. The predictive models under the three walking tasks showed similar performance.

Background:The application of dual-task walking paradigms for gait assessment in stroke patients is critical, where varying concurrent tasks may elicit distinct gait patterns of dual-task interference. This study assessed the acute effects of different types of dual tasks on gait in stroke patients during task performance, informing occupational, and physical therapists about care recommendations to prevent patients from falling and improve their balance function in daily life. Methods:A total of 19 stroke patients (52.7 ± 6.9 years old) performed the walking-only and dual-task walking (motor, arithmetic and speech) task test while a 3D motion capture system measured the gait parameters (the gait spatial-temporal parameters, sagittal angle of lower-limb joints, gait parameter variability and dual-task cost). One-way repeated measures ANOVA was used to test the effects of the above four walking conditions on gait parameters. Results:Arithmetic task and speech task interference can affect the gait of stroke patients (P < 0.05). Arithmetic task interference has the greatest impact on step speed, cadence, single support phase, hip joint range in support period and has the greatest dual-task cost, speech task interference has the greatest impact on cadence coefficient of variation (P < 0.05). The motor task was not significantly different from walking-only (P >0.05). Conclusion:Both arithmetic and speech tasks have a great impact on gait in stroke patients. Faced with cognitive interference, stroke patients spontaneously adopted a "cautious gait" walking pattern. In future rehabilitation training, diversity of task types is critical for gait rehabilitation training based on the walking ability of the patients.

Spatio-temporal parameters provide reference information for the gait variations of stroke patients during obstacle crossing. Analyzing these gait spatio-temporal characteristics of patients during obstacle crossing can assist in assessing the risk of falls. The aim of this study was to analyze the variances in gait spatio-temporal characteristics during obstacle crossing between stroke patients with and without a history of falls, to explore spatio-temporal parameters for assessing fall risk, and to construct a regression model for predicting patients’ fall risk. Thirty-three patients with unilateral brain injury from stroke who were discharged from rehabilitation were included. These patients were categorized into a falls group (with a history of falls) and a non-falls group (without a history of falls) based on whether they had experienced a fall in the previous six months. A Qualisys motion capture system was used to record the marker positions when crossing an obstacle 4 cm in height with the affected leg as the leading limb, and gait spatio-temporal parameters were calculated and obtained. Univariate analysis and logistic regression models were used to compare the gait spatio-temporal parameters of the two groups. 17 participants were categorised into the falls group and 16 into the non-falls group. The single support phase of leading limb, post-obstacle swing phase of trailing limb, obstacle-heel distance of leading limb, and obstacle-heel distance of trailing limb were significantly smaller in the fall group compared to the non-fall group (P < 0.05). The gait spatio-temporal parameter ultimately included in the fall risk prediction model was the obstacle-heel distance of leading limb (OR = 0.819, 95

BACKGROUND:Dual-task gait training often improves walking ability in stroke patients, but its effect on lower-limb coordination and the effects of different training types remains unclear. Improving lower-limb coordination could decrease fall risk during walking. RESEARCH QUESTION:To observe the rehabilitation effect of cognitive dual-task gait training (CDTG) and motor dual-task gait training (MDTG) on lower-limb coordination during walking in subacute stroke patients. METHODS:Thirty-five subacute stroke patients were randomly assigned to the CDTG group (n = 18) and the MDTG group (n = 17), receiving cognitive dual-task gait training and motor dual-task gait training, respectively, three times a week for 4 weeks. If training benefits lower-limb coordination, a larger mean continuous relative phase (MCRP) and smaller variability (MCRPV) should be observed during walking. RESULTS:After training, the MCRP of the bilateral hip joints increased during the stance phase of the affected side in both groups (P = 0.034), while the MCRPV of the bilateral hip joints decreased significantly (P = 0.024). During the swing phase of the affected side, the MCRPV between the hip and knee joints of the unaffected side (P = 0.001), the knee and ankle joints of the unaffected side (P = 0.011), and the two knee joints (P = 0.048) all decreased. There was no difference between the two groups before and after training. SIGNIFICANCE:Four weeks of cognitive dual-task gait training and motor dual-task gait training can effectively improve lower-limb coordination in subacute stroke patients, and there is no difference in the effects of the two training methods.

BACKGROUND:In daily life, stroke patients frequently experience falls during obstacle crossing. Analyzing the gait characteristics of patients in high-risk falling scenarios can help identify and predict fall risks. RESEARCH QUESTION:Exploring the predictive power of gait characteristics during obstacle crossing for fall risk in stroke patients. METHODS:Recruitment of 38 stroke patients with unilateral hemiplegia discharged from rehabilitation. A Qualisys motion capture system and two Kistler force plates were used to record the marker positions and the ground reaction forces during crossing an obstacle 4 cm in height with the affected limb as the leading limb. Gait spatio-temporal parameters, joint angles, and joint moments were calculated. Following a 12-month follow-up survey to collect data on falls among participants, independent samples t-test and binary logistic regression models were employed to identify predictors associated with future fall risk. RESULTS:During the follow-up period, 13 participants experienced at least one fall and were categorized into the fall group; 14 participants did not experience any falls and were categorized into the non-fall group. Binary logistic regression analysis revealed that the toe-clearance distance of the trailing limb, as well as the peak ankle plantarflexion moment of the trailing limb during double support phase, are effective predictors of fall risk in stroke patients (P < 0.05). The overall correct prediction rate of the regression model incorporating both factors was 85.2 %. SIGNIFICANCE:Gait analysis during obstacle crossing holds potential clinical value in identifying future fall risk in stroke patients.

Abstract Background To determine the effects of negative heel shoes on perceived pain and knee biomechanical characteristics of runners with patellofemoral pain (PFP) during running. Methods Sixteen runners with PFP ran in negative (−11 mm drops) and positive (5 mm drops) heel shoes while visual analog scale (VAS) scores, retroreflective markers, and ground reaction force were acquired by applying a 10‐cm VAS, infrared motion capture system, and a three‐dimensional force plate. Knee moment, patellofemoral joint stress (PFJS), and other biomechanical parameters during the stance phase were calculated based on inverse dynamics and a biomechanical model of the patellofemoral joint. Results The foot inclination angle, peak PFJS during the stance phase, patellofemoral joint reaction force, knee extension moment, and quadriceps force at the time of peak PFJS of runners with PFP in negative heel shoes were lower than that in positive heel shoes, no significant difference was found in VAS scores, knee flexion angle, patellofemoral contact area, and quadriceps moment arm at the time of peak PFJS. Conclusions Compared to positive heel shoes, running in negative heel shoes decreases peak PFJS in runners with PFP, which may decrease patellofemoral joint loading, thus reducing the possibility of further development of PFP. Trail Registration Sports Science Experiment Ethics Committee of Beijing Sport University. 2023095H, April 18, 2023 (prospectively registered).

Background: We compared the effects of whole -body vibration training and proprioceptive neuromuscular facilitation on the biomechanical characteristics of the lower limbs in functional ankle instability patients during cutting movement to ascertain the superior rehabilitation method. Methods: Twenty-two male College students with unilateral functional ankle instability volunteered for this study and were randomly divided into whole -body vibration training group and proprioceptive neuromuscular facilitation group. Kinematics data and ground reaction forces were collected using infrared motion capture system and 3-D force plates synchronously during cutting. Repeated measures two-way ANOVA was performed to analyze the data. Findings: Both training methods reduced the maximum hip abduction angle (p = 0.010, effect size: proprioceptive neuromuscular facilitation = 0.69; whole -body vibration training = 0.20), maximum knee flexion angle (p = 0.008, effect size: proprioceptive neuromuscular facilitation = 0.39, whole -body vibration training = 1.26) and angular velocity (p = 0.014, effect size: proprioceptive neuromuscular facilitation = 0.62, whole -body vibration training = 0.55), maximum ankle inversion angular velocity (p = 0.020, effect size: proprioceptive neuromuscular facilitation = 0.52, whole -body vibration training = 0.81), and knee flexion angle at the time of maximum vertical ground reaction forces (p = 0.018, effect size: proprioceptive neuromuscular facilitation = 0.27, wholebody vibration training = 0.76), and increased the maximum ankle dorsiflexion moment (p = 0.049, effect size: proprioceptive neuromuscular facilitation = -0.52, whole -body vibration training = -0.22). Whole -body vibration training reduced the maximum ground reaction forces value in the mediolateral directions (p = 0.010, effect size = 0.82) during cutting movement. Interpretation: These findings suggested that the two types of training might increase neuromuscular conduction function around the ankle. After these two types of training, functional ankle instability patients showed a similar risk of injury to the lateral ankle ligaments during cutting.

ObjectiveTo ascertain the immediate changes in stroke patients’ temporal and spatial parameters of gait and the joint angles of stroke patients throughout the entire gait cycle following the application of lower extremity elastic strap binding technique.MethodsTwenty-nine stroke patients were invited as the study participants. The patient seated, flexed the hip and knee, utilized a 5 cm-wide elastic strap, positioning its midpoint beneath the affected foot and crossing it anterior to the ankle joint. Upon standing, the strap encircled the posterior aspect of the lower leg, proceeded around the back of the knee, and ascended the thigh on the affected side. Crossing anteriorly over the thigh, it then encircled the back of the waist before being secured in place. Using Qualisys motion capture system to collect kinematic data of the lower extremities during walking while wearing shoes only or strapping. A paired sample t-test was used to analyze the effects of the technique on gait spatiotemporal parameters and joint angles in stroke patients.ResultsThe patients’ step length decreased (P = 0.024), and step width increased (P = 0.008) during the gait cycle after the strapping. In the gait cycle between 0% and 2%, 7%–77%, and 95%–100%, the hip flexion angle on the affected side was significantly larger after the strapping (P < 0.05). In the gait cycle between 0% to 69% and 94%–100%, the knee flexion angle on the affected side was significantly larger after the strapping (P < 0.05). In the gait cycle between 0% to 57% and 67%–100%, the ankle dorsiflexion angle on the affected side was significantly smaller after the strapping (P < 0.05), and in the gait cycle between 0% to 35% and 68%–100%, the ankle inversion angle on the affected side was significantly smaller after the strapping (P < 0.05).ConclusionThe lower extremity elastic strap binding technique can decrease the hip flexion and knee flexion limitations in stroke patients during walking, and reduce the ankle plantar flexion and ankle inversion angle of stroke patients. The lower extremity elastic strap binding technique enabled stroke patients to adopt a more stable gait pattern.

目的 基于身体不同位置的加速度信号,比较采用不同算法获取的评价功能性踝关节不稳(FAI)者动态姿势稳定性指标的重测信度和鉴别效度.方法 2021年4月至6月于北京体育大学招募21例单侧FAI患者和21例踝关节正常者.3个惯性传感器粘贴于腰点、膝和踝位置.通过三维测力台和惯性传感器同步采集受试者多方向单腿落地测试中的地面反作用力(GRF)和运动学数据.采用无界三阶多项式(UTOP)拟合法计算稳定时间,通过均方根值计算稳定指数.结果 基于加速度信号与基于GRF计算的大部分指标相关,但相关系数较低(|r| = 0.116～0.368,P＜0.05).基于身体不同位置的加速度信号得到的稳定时间和稳定指数表现出低到高的重测信度(CMC 0.30～0.91).对女性受试者,基于加速度信号的稳定时间中,有11个评价指标达到一般至很高的鉴别效度(AUC = 0.702～0.942,P＜0.05);稳定指数中,有8个指标达到一般水平的鉴别效度(AUC = 0.717～0.782,P＜0.05).不同算法在男性受试者中未取得良好的鉴别效果.结论 基于腰点位置的加速度信号并应用UTOP算法计算的稳定时间,能够评价女性FAI患者单腿落地动作的动态姿势稳定性,具有较高的鉴别效度和中等至高的重测信度.

Background: Minimalist shoe is one of the optional shoes applied to elicit biomechanics improvement for patients with knee osteoarthritis during walking. However, few reviews investigated the effect of minimalist shoes on patients with knee osteoarthritis.Research question: What is the effect of minimalist shoes on biomechanical and clinical outcomes for KOA? Compared with other shoes, should minimalist shoes be recommended for KOA patients during gait retraining?Methods: five databases were systematically searched before Feb 2023. Peer-reviewed studies assessed the clinical or biomechanical effects of minimalist shoe were included. The methodological quality of studies was assessed for inclusion in meta-analysis.Results: 10 studies involving 512 participants (43% male and 57% female) were included. For acute biomechanical outcomes, the first knee adduction moment (SMD: −0.39; 95% CI: −0.57, –0.20) and knee angular adduction impulse (SMD: −0.53; 95% CI: −0.83 to -0.23) were found to significantly decrease, and both were significant in subgroup comparison with stable shoe. Lower stride length and higher cadence trend were observed. With a high heterogeneity, knee function-oriented outcomes showed a non-significant result.Significance: The short-term decrease of biomechanical risk factors could be considered to further apply in a short-term clinical gait retraining task. Lower stride length and higher cadence trends reflect the mechanism of reduction. Future designs could choose stable shoes first as the control condition.

目的:系统评价可能导致髌股关节痛的生物力学危险因素.方法:检索资料库包括PubMed、Embase、Web of Science,以及中国知网、万方、维普,检索时限至2022年5月,筛选与髌股关节痛生物力学危险因素有关的前瞻性研究,提取运动学、动力学和肌电数据,采用Review Manager 5.3进行Meta分析.结果:最终纳入11项研究,总样本量6 587人,其中388人发生髌股关节痛.有限的证据表明较大的膝外翻是髌股关节痛的危险因素[I2=97％,SMD=1.32,95％CI(0.36,2.29)].亚组分析显示非常有限的证据表明较大的膝外翻是女性髌股关节痛的危险因素[I2=98％,SMD=2.49,95％CI(0.03,4.95)],而有限的证据表明较大的膝外翻不是男性髌股关节痛的危险因素[I2=81％,SMD=0.43,95％CI(-0.26,1.12)].髌股关节痛发病人群和未发病人群在其他运动学、动力学和肌电特征中未表现出显著性差异.结论:功能性活动中的膝外翻可能是女性产生髌股关节痛的生物力学危险因素,但是支持证据非常有限,且研究间具有较高的异质性.