Balance is a fundamental quality for trampoline athletes, the basis for completing complex skills. We aimed to compare balance control strategies between elite trampolinists (ETs) and sub-elite trampolinists (Sub-ET) by integrating linear and nonlinear center of pressure (COP) measures across stable and unstable surfaces. Twenty-four male athletes (12 ET, 12 Sub-ET) participated. Each participant performed 15-s static standing trials with eyes closed on a firm surface (FI) and a foam surface (FO). COP parameters were extracted, including ellipse area, sway velocity, sway range, and sample entropy (SampEn) in the medio-lateral (ML) and antero-posterior (AP) directions. Repeated-measures ANOVA was applied to examine the effects of group and surface condition. Linear analyses indicated that ET athletes exhibited greater sway amplitudes and faster velocities than Sub-ET athletes, with both groups showing larger sway on FO compared with FI. Nonlinear analyses revealed that ET athletes demonstrated lower SampEn, suggesting more structured and automatized control strategies. ET athletes maintained consistent entropy across both conditions, reflecting stronger adaptability to unstable surfaces. These results emphasize the importance of combining linear and nonlinear measures in balance assessment and suggest that incorporating unstable or trampoline-like surfaces into training may enhance adaptability, improve performance, and reduce injury risk.

Purpose: To study the differences in lower limb muscle explosive and maximal strength among trampoline athletes at different levels of competition. Methods: A total of fifteen trampoline athletes, comprising seven elite and eight non-elite athletes, participated in this project. Lower limb explosive strength was assessed using the countermovement jump (CMJ) test. Maximal strength was evaluated by the MicroFet portable system. The maximal strength of the hip, knee, and ankle were measured and standardized by weight. Independent t-tests were employed to examine the differences between the two groups. Cohen's d was used to evaluate the related effect size. Small, medium, and large effect sizes are represented by 0.20 ≤ d < 0.50, 0.50 ≤ d < 0.80, and d ≥ 0.80, respectively. Results: Significant differences were observed in the CMJ performance between the two groups. The take-off velocity of elite athletes (2.91±0.17m/s) was higher than that of non-elite athletes (2.63±0.24 m/s, p=0.023, d=1.328). Additionally, the jump height increased from elite athletes (0.42±0.05m) to non-elite athletes (0.32±0.06m, p=0.009, d=1.591). Furthermore, elite athletes demonstrated higher average power output (32.79±3.49W/kg) compared to non-elite athletes (27.10±3.51W/kg, p=0.008, d=1.627). The reactive strength index in the non-elite athletes (0.75±0.12m/s) was lower than in the elite athletes (0.96±0.15m/s, p=0.011, d=1.530). However, no significant differences were observed in relative muscle strength of the lower limb (hip, knee, and ankle) between the two groups (p > 0.05). Conclusion: For trampoline athletes, the explosive strength of the lower limbs appears to have a more pronounced effect on performance than maximal strength. Therefore, developing the explosive strength of the lower limbs may be crucial for enhancing the performance of trampoline athletes.

We aimed to examine the changes in balance performance, kinematic variables, and joint coordination of the lower extremities during the Y-balance learning task. Twenty female university students completed five consecutive blocks of Y-balance learning from days 3 to 7 (135 trials). Pre-tests and tests were performed on days 1 and 9. Maximum reach distance, peak joint angle, and joint coordination in the anterior (AL), posterolateral (PL), and posteromedial (PM) directions were measured to determine the efficacy of Y-balance performance. A repeated measures ANOVA was performed for the maximum reach distance across learning blocks to confirm whether learning had occurred. Our results indicated that the maximum reach distance on day 5 was longer than that on other learning days. The maximum reach distance significantly increased in the PL and PM directions after learning. The hip flexion (PL/PM), abduction (PM), internal rotation (PM), and external rotation (PL) angles increased after learning. The knee joint flexion angle increased in both AL and PL directions. Only the ankle dorsiflexion angle increased in the AL direction. Joint coordination indicated that the knee and hip joints performed simultaneously during internal rotation. Ankle-knee joint coordination was performed using dorsiflexion and flexion strategies. Statistical parametric mapping analysis indicated significant differences in the ankle sagittal plane in the AL direction, hip horizontal and hip/knee sagittal planes in the PL direction, and hip/knee sagittal and hip frontal/horizontal planes in the PM direction. These data suggest that the dynamic balance ability of the novice participants improved in relation to changes in coordination patterns after learning. The results of this study can be applied to other populations to improve their dynamic balance and prevent fall injuries.

Physiologic hand tremors are a critical factor affecting the aim of air pistol shooters. However, the extent of the effect of hand tremors on shooting performance is unclear. In this study, we aim to explore the relationship between hand tremors and shooting performance scores as well as investigate potential links between muscle activation and hand tremors. In this study, 17 male air pistol shooters from China’s national team and the Air Pistol Sports Center were divided into two groups: the elite group and the sub-elite group. Each participant completed 40 shots during the experiment, with shooters’ hand tremors recorded using three-axis digital accelerometers affixed to their right hands. Muscle activation was recorded using surface electromyography on the right anterior deltoid, posterior deltoid, biceps brachii (short head), triceps brachii (long head), flexor carpi radialis, and extensor carpi radialis. Our analysis revealed weak correlations between shooting scores and hand tremor amplitude in multiple directions (middle-lateral, ML: r2 = −0.22, p < 0.001; vertical, VT: r2 = −0.25, p < 0.001), as well as between shooting scores and hand tremor complexity (ML: r2 = −0.26, p < 0.001; VT: r2 = −0.28, p < 0.001), across all participants. Notably, weak correlations between shooting scores and hand tremor amplitude (ML: r2 = −0.27, p < 0.001; VT: r2 = −0.33, p < 0.001) and complexity (ML: r2 = −0.31, p < 0.001) were observed in the elite group but not in the sub-elite group. Moderate correlation were found between the biceps brachii (short head) RMS and hand tremor amplitude in the VT and ML directions (ML: r2 = 0.49, p = 0.010; VT: r2 = 0.44, p = 0.025) in all shooters, with a moderate correlation in the ML direction in elite shooters (ML: r2 = 0.49, p = 0.034). Our results suggest that hand tremors in air pistol shooters are associated with the skill of the shooters, and muscle activation of the biceps brachii (long head) might be a factor affecting hand tremors. By balancing the agonist and antagonist muscles of the shoulder joint, shooters might potentially reduce hand tremors and improve their shooting scores.

High loading impact associated with heel strikes causes running injuries. This study aimed to investigate how loading impact is affected by midsole hardness and running surface type. Twelve young rear-foot runners ran at a fixed speed along an 18 m runway wearing shoes with different midsole hardness (Asker C-45, C-50, C-55, C-60, from soft to hard) and on two different surfaces (rubber and concrete). We quantified vertical average loading rate (VALR) and vertical impact peak force (VIPF). We conducted midsole × surface repeated-measures ANOVA on loading impact measures, and one-sample t-tests to compare VALR with a threshold value (80 BW·s-1). Midsole hardness and surface type mainly affected VALR. Although no significant effect of these variables was observed for VIPF magnitude, there were effects on time to VIPF and steps with VIPF. Several combinations of midsole and surface hardness reduced VALR below 80 BW·s-1: Asker C-45 with both surfaces, and Asker C-50 with a rubber surface. The combination of softer midsole and surface effectively reduced loading rates as shown by increased time to VIPF and reduced VALR. Combining softer midsole and surface results in the greatest cushioning, which demonstrates the benefit of considering both factors in reducing running injuries.

Uphill walking is a common task encountered in daily life, with steeper inclines potentially imposing greater biomechanical and neuromuscular demands on the human body. The heel-to-toe drop (HTD) in footwear may influence the biomechanical and neuromuscular pattern of uphill walking; but the impact remains unclear. Adjustments in HTD can modulate biomechanical and neuromuscular patterns, mitigating the demands and optimizing the body’s response to different inclinations. We hypothesize that adjustments in HTD can modulate biomechanical and neuromuscular patterns, mitigating the demands and optimizing the body’s response to different inclinations. Nineteen healthy men walked on an adjustable slope walkway, with varied inclinations (6°, 12°, 20°) and HTD shoes (10mm, 25mm, 40 mm), while the marker positions, ground reaction forces and electromyography data were collected. Our study reveals that gait temporo-spatial parameters are predominantly affected by inclination over HTD. Inclination has a more pronounced effect on kinematic variables, while both inclination and HTD significantly modulate kinetic and muscle synergy parameters. This study demonstrates that an increase in the inclination leads to changes in biomechanical and neuromuscular responses during uphill walking and the adjustment of HTD can modulate these responses during uphill walking. However, the present study suggests that an increased HTD may lead to elevated loads on the knee joint and these adverse effects need more attention.

Introduction: Musculoskeletal simulation has been widely used to analyze athletes' movements in various competitive sports, but never in ski jumping. Aerodynamic forces during ski jumping take-off have been difficult to account for in dynamic simulation. The purpose of this study was to establish an efficient approach of musculoskeletal simulation of ski jumping take-off considering aerodynamic forces and to analyze the muscle function and activity. Methods: Camera-based marker-less motion capture was implemented to measure the take-off kinematics of eight professional jumpers. A suitable full-body musculoskeletal model was constructed for the simulation. A method based on inverse dynamics iteration was developed and validated to estimate the take-off ground reaction force. The aerodynamic forces, which were calculated based on body kinematics and computational fluid dynamics simulations, were exerted on the musculoskeletal model as external forces. The activation and joint torque contributions of lower extremity muscles were calculated through static optimization. Results: The estimated take-off ground reaction forces show similar trend with the results from past studies. Although overall inconsistencies between simulated muscle activation and EMG from previous studies were observed, it is worth noting that the activation of the tibialis anterior, gluteus maximus, and long head of the biceps femoris was similar to specific EMG results. Among lower extremity extensors, soleus, vastus lateralis, biceps femoris long head, gluteus maximus, and semimembranosus showed high levels of activation and joint extension torque contribution. Discussion: Results of this study advanced the understanding of muscle action during ski jumping take-off. The simulation approach we developed may help guide the physical training of jumpers for improved take-off performance and can also be extended to other phases of ski jumping.

目的:研究女性不对称负重行走时下肢关节力矩特征,探讨负重侧和无负重侧下肢关节适应机制,为分析女性不对称负重行走可能出现的下肢关节损伤提供依据.方法:16例健康女性采用单肩背包的不对称负重方式以自身体重的0％、5％、10％、15％4种负重重量行走,使用Motion红外高速运动捕捉系统和Kistler三维测力台同步采集运动学和动力学数据.结果:不对称负重会显著减小负重侧下肢膝关节外翻力矩(P＜0.05),显著增加无负重侧下肢膝关节外翻力矩和髋关节外展力矩(P＜0.05);无负重侧下肢膝关节外翻力矩和髋关节外展力矩显著高于负重侧下肢(P＜0.05),且两侧差异随着负重重量增加而增大.结论:不对称负重行走,对无负重侧肢体有更大的要求.无负重侧下肢膝关节外翻力矩、髋关节外展力矩均大于负重侧,这种改变可能与关节退变和骨性关节炎的发生相关.

Objective: To investigate the effects of foot sole insensitivity on the outcomes of the triceps surae muscle H-reflex and functional gait.Material and Methods: People with peripheral neuropathy were recruited and divided into two groups: people with more (n = 13, 73.3 ± 4.3 years old) or less (n = 10, 73.5 ± 5.3) sensitive tactile sensation. Their monofilament testing scores were 9.0 ± 1.5 (range: 7–10) and 2.3 ± 2.4 (range: 0–6) out of 10, respectively. H-reflex of the triceps surae muscles during quiet standing and their relationship with functional gait, 6 min walking distance (6MWD), and timed-up-and-go duration (TUG), were compared between groups.Results: No significant difference was detected for H-reflex parameters between the groups. The less sensitive group showed reduced (p < .05) functional gait capacity compared to the other group, 38.4 ± 52.7 vs. 463.5 ± 47.6 m for 6MWD, and 9.0 ± 1.5 vs. 7.2 ± 1.1s for TUG, respectively. A significant correlation (p < .05), worse functional gait related to greater H/M ratio, was observed in the less sensitive group, not the other group.Conclusion: Although there was no significant H-reflex difference between the groups, more pronounced tactile sensation degeneration affected functional gaits and their relationship with H-reflex.

目的:探讨楼梯坡度对健康成人上楼梯行走时膝关节负荷等生物力学特征的影响.方法:10名健康成年男性完成高、中、低坡度的上楼梯行走测试,采用Motion红外高速运动捕捉系统和Kistler三维测力台同步采集受试者的体表标志点坐标和地面反作用力数据,建立下肢骨骼肌肉模型,获得支撑相的膝关节三维角度和三维净力矩,计算髌股关节应力最大值和胫股关节内侧接触力第1峰值时刻的膝关节生物力学参数,并采用单因素重复测量方差分析确定不同楼梯坡度对各参数的影响.结果:上中坡度的楼梯时,髌股关节应力最大值以及应力最大值时刻的伸膝力矩大于低坡度(P<0.05);髌股关节应力最大值时刻的髌股关节接触力、股四头肌肌力以及胫股关节内侧接触力第1峰值的伸膝力矩,上高、中坡度楼梯时均大于低坡度(P<0.05);髌股关节应力最大值时刻的屈膝角度与髌股关节接触面积随着楼梯坡度的增加而增大,应力最大值时刻的股四头肌力臂随着楼梯坡度的增加而减小(P<0.05);胫股关节内侧接触力第1峰值及第1峰值的膝内收力矩未受楼梯坡度影响(P>0.05).结论:与上低坡度楼梯行走相比,上中坡度楼梯会增加髌股关节应力最大值,进而可能会增加髌股关节负荷,从而导致髌股关节损伤风险增加.

Objective:This study compared the difference of motor coordination between athletes and non-athletes running at different speeds,to clarify the change of coordination among different speeds,and to determine the effect of training on coordination.Methods:32 male college students(16 athletes and 16 non-athletes)participated in this study.3D kinematic data at different speeds running were collected,intra-limb and inter-limb continuous relative phase(CRP)were calculated,and repeated-measurement AVOVA was performed to determine the difference of coordination between two groups at different speeds.Results:Inter-limb and intra-limb coordination both changed among running speeds.Knee-ankle decreased,hip-hip and knee-knee increased with running speeds increased,and hip-knee,ankle-ankle changed differently in different gait phase.The effects of group on coordination were found in sprint instead of the other two speeds.Conclusions:With the increasing of running speed,CRP of distal joints decreased,suggesting that it played an important role in gait stability,while proximal joints were mainly related to motor tasks.The motor control strategies of athletes were the same as non-athletes in slow speed running but significantly improved in the sprint.

目的:通过分析我国优秀男子跳台滑雪运动员实地起跳阶段运动学、起跳运动模式等指标,探究影响我国男子跳台滑雪运动员飞行距离的主要起跳因素.方法:1)选择8名我国男子跳台滑雪运动员作为研究对象,在日本长野县白马村K90跳台训练基地采集3次起跳阶段二维运动学数据,采用广义估计模型(GEE)分析影响飞行距离的实地起跳阶段运动学因素.2)截取平昌冬奥会排名前10的男子跳台滑雪选手决赛起跳阶段视频数据,采用单因素方差分析研究国内外运动员起跳阶段特定时刻肢体角度差异.3)实验室内使用1台Z camera高速摄像机和1块Kistler 9281EA测力台采集运动员静蹲跳(squat jump,SJ)、反向跳(countermovement jump,CMJ)、模拟跳跃(imitation jump,IJ)、下落跳(drop jump,DJ)的动力学及运动学数据,采用Pearson相关分析检验实验室内运动学及动力学指标与飞行距离间的相关性.结果:1)在实地起跳阶段运动学方面,起跳起始时刻躯干与助滑道夹角、小腿与助滑道夹角、髋关节角、膝关节角,以及起跳阶段的髋关节峰值角速度、膝关节平均角速度、起跳结束时刻膝关节角及髋关节角为飞行距离的影响因素(P<0.05).2)在起跳阶段运动模式及力量特点方面,IJ重心最低处膝外翻指数(r=0.731)、DJ膝外翻最小值(r=0.713)、CMJ起跳阶段地面反作用力峰值(r=0.710)、CMJ蹬伸冲量(r=0.752)、SJ(r=0.723)及CMJ起跳峰值功率(r=0.762)均与飞行距离呈正相关.3)对比国内外运动员起跳阶段特定时刻肢体角度发现,国外优秀运动员起跳起始时刻小腿与助滑道夹角(53.54°±3.14°)显著小于我国运动员(57.62°±4.62°),出台瞬间小腿与助滑道夹角(58.22°±2.13°)显著小于我国运动员(65.59°±3.84°),大腿与助滑道夹角(73.28°±6.15°)显著大于我国运动员(58.77°±3.16°),起跳阶段结束时刻髋关节角度(175.23°±1.96°)显著大于我国运动员(156.37°±13.13°).结论:我国跳台滑雪运动员起跳阶段起跳起始时刻应尽量降低身体重心以减少阻力,并适当提高膝关节角来提高出台后肢体伸展程度.起跳过程中提高膝关节蹬伸力量,同时适当降低髋关节伸展速度,避免风阻对躯干造成不利影响.室内及实地训练过程中,应在提升蹬伸爆发力的同时避免膝关节过度外翻,提高蹬伸力量及传递效率.

Changes in midsole thickness can influence cushioning and rearfoot stability in running, but no information has been established in basketball. This study aimed to investigate whether midsole thickness would alter ground reaction force, ankle stability and performance-related indicators in four basketball manoeuvres. Fifteen university basketball athletes performed lateral shuffle, forward sprint, counter-movement jump (CMJ) and drop landing in basketball shoes of five midsole thicknesses (Thinnest, Thin, Medium, Thick, Thickest). One-way repeated-measures ANOVA was performed on each of the biomechanics and performances variables and Friedman test was performed on comfort perceptions. Our findings found a significant midsole thickness effect on the lower extremity biomechanics (p < 0.05), with better traction (p = 0.019) and greater plantarflexion (p = 0.019) while sprinting with thinner shoe conditions. Thicker basketball shoes led to greater rearfoot inversion (p = 0.004) and a more significant inversion velocity peak (p = 0.019) during lateral shuffling. No significant difference in peak impact force or peak loading rate was observed between shoes during drop landing. These findings suggest that participants wearing basketball shoes with thicker midsole may lead to ankle instability during lateral shuffling manoeuvres. Wearing basketball shoes with thinner midsoles may be beneficial for sprint and jump performances.

目的:对比髌股关节痛业余跑者在有痛和无痛2种状态下跑步和落地起跳缓冲期的运动学和动力学数据,确定膝痛对膝关节生物力学特征的影响.方法:筛查选取15名男性和10名女性髌股关节痛业余跑者作为受试者并完成研究.每名受试者分别在有痛和无痛2种状态下完成生物力学测试,膝痛的诱发与消除通过改变跑量完成.采集所有受试者在跑步和落地起跳时的膝关节运动学和动力学数据.采用混合设计的双因素方差分析确定疼痛状态与性别对跑步和落地起跳缓冲期膝关节生物力学特征的影响.结果:男性和女性髌股关节痛业余跑者在有痛状态下跑步(P=0.001)和落地起跳(P=0.011)缓冲期的最大膝外展角度小于无痛状态.男性和女性髌股关节痛业余跑者在有痛状态下落地起跳缓冲期的膝伸力矩峰值(P=0.003)和髌股关节应力峰值(P=0.001)小于无痛状态.结论:膝痛会降低男性和女性髌股关节痛业余跑者在跑步和落地起跳缓冲期的最大膝外展角度,以及落地起跳缓冲期的膝伸力矩峰值和髌股关节应力峰值.膝痛代偿性地降低了髌股关节负荷,可能属于一种保护机制.

Purpose: The project was to examine the influence of peripheral neuropathy (PN) severity on the relationship between Hoffmann-reflex (H-reflex) and postures.Methods: A total of 34 participants were recruited. H-reflex (H/M ratio and H-index) during prone, standing, and the heel-contact phase of walking was tested, along with foot sole sensitivity.Results: The participants were divided into three groups based on the severity of the foot sole sensitivity deficit: control, less (LA), and more (MA) affected with both feet 5.07 monofilament test scores ranging 10, 0–5, and 6–9, respectively. A significant group by the posture interaction was observed in the H/M ratio (F3.0, 41.9 = 2.904, p = 0.046, ηp2 = 0.172). In the control group, the H/M ratio of prone (22 ± 7%) was greater than that of the standing (13 ± 3%, p = 0.013) and heel-contact phase (10 ± 2%, p = 0.004). In the MA group, the H/M ratio of standing (13 ± 3%) was greater than that of the heel-contact phase (8 ± 2%, p = 0.011). The H-index was significantly different among groups (F2,28 = 5.711, p = 0.008, and ηp2= 0.290). Post hoc analysis showed that the H-index of the control group (80.6 ± 11.3) was greater than that of the LA (69.8 ± 12.1, p = 0.021) and MA groups (62.0 ± 10.6, p = 0.003).Conclusion: In a non-PN population, the plantar sensory input plays an important role in maintaining standing postural control, while as for the PN population with foot sole sensitivity deficiency, type Ⅰ afferent fibers reflex loop (H-reflex) contributes more to the standing postural control. The H-index parameter is an excellent method to recognize the people with and without PN but not to distinguish the severity of PN with impaired foot sole sensitivity.

Large and repeated impacts on the heel during running are among the primary reasons behind runners’ injuries. Reducing plantar pressure can be conducive to reducing running injury and improving running performance and is primarily achieved by modifying the design parameters of running shoes. This study examines the effect of design parameters of running shoes (i.e., heel-cup, insole material, midsole material, and insole thickness) on landing peak plantar pressure and determines the combination of different parameters that optimize cushion effects by employing the Taguchi method. We developed the foot–shoe finite element (FE) model through reverse engineering. Model assembly with different design parameters was generated in accordance with the Taguchi method orthogonal table. The effectiveness of the model was verified using the static standing model in Ansys. The significance and contribution of different design parameters, and the optimal design to reduce plantar pressure during landing, were determined using the Taguchi method. In the descending order of percentage contribution was a conforming heel-cup (53.18%), insole material (25.89%), midsole material (7.81%), and insole thickness (2.69%). The more conforming heel-cup ( p < 0.001) and softer insole ( p = 0.001) reduced the heel pressure during landing impact. The optimal design of running shoe in this study was achieved with a latex insole, a 6 mm insole thickness, an Asker C-45 hardness midsole, and a 100% conforming heel-cup. The conforming heel-cup and the insole material significantly affected the peak plantar pressure during heel landing. The implementation of a custom conforming heel-cup is imperative for relieving high plantar pressure for long-distance heel-strike runners.

We investigated how midfoot stiffness of running shoes influences foot segment kinematics and ground reaction force (GRF) during heel-toe running. Nineteen male rearfoot strike runners performed overground heel-toe running at 3.3 m/s when wearing shoes with different midfoot bending stiffnesses (low, medium, and high) in a randomized order. A synchronized motion capture system (200 Hz) and force plate (1000 Hz) were used to collect the foot-marker trajectories and GRF data. Foot kinematics, including rearfoot-lab, midfoot-rearfoot, forefoot-rearfoot, and forefoot-midfoot interactions, and kinetics, including GRF characteristics, were analyzed. Our results indicated that high midfoot stiffness shoes reduced the forefoot-rearfoot range of motion (mean ± SD; high stiffness, 7.8 ± 2.0°, low stiffness, 8.7 ± 2.1°; p < 0.05) and forefoot-midfoot range of motion (mean ± SD; high stiffness, 4.2 ± 1.1°, medium stiffness, 4.6 ± 0.9°; p < 0.05) in the frontal plane. No differences were found in the GRF characteristics among the shoe conditions. These findings suggest that an increase in midsole stiffness only in the midfoot region can reduce intersegmental foot medial-lateral movements during the stance phase of running. This may further decrease the tension of the foot muscles and tendons during prolonged exercises.

背景:护膝常被跑步爱好者用于预防和治疗髌股关节痛,但其所起到的干预作用机制仍不清楚.目的:确定护膝对不同性别髌股关节痛跑步爱好者跑步时主观痛感、下肢运动学和动力学特征的影响.方法:选取11名男性和9名女性髌股关节痛跑步爱好者作为受试者,通过目测类比量表、红外运动捕捉系统和测力台采集受试者在有、无穿戴髌骨稳定型护膝跑步时的主观痛感、运动学和动力学数据.研究通过北京体育大学运动科学实验伦理委员会批准,批准号:2020021H.参与试验的受试者均为自愿参加,对试验过程完全知情同意.结果 与结论:①男性和女性受试者在有护膝时跑步的目测类比量表得分小于无护膝时(P＜0.01);②女性受试者在有护膝时跑步缓冲期的最大膝屈角度小于无护膝时(P＜0.01),但男性在有、无护膝时跑步缓冲期的最大膝屈角度未出现差异(P＞0.05);男性和女性受试者在有护膝时跑步缓冲期的最大髋内收角度小于无护膝时(P＜0.01);男性和女性患者在有护膝时跑步缓冲期的膝外展(P＜0.01)和外旋力矩峰值(P＜0.01)大于无护膝时;③结果说明,护膝降低了男性和女性髌股关节痛跑步爱好者跑步时的主观痛感;减小了女性跑步时的最大膝屈角度和髋内收角度,以及男性跑步时的最大髋内收角度,护膝对下肢运动学特征的影响具有性别特异性;增大了男性和女性跑步时的膝外展和外旋力矩峰值,护膝可能引起膝关节负荷增大.

目的:确定男性青年在不同坡角斜坡行走时下肢运动学及动力学特征,探究在不同坡角下坡行走时的步态控制策略以及产生改变的坡角大小.方法:运用动作捕捉系统同步采集10名男性青年在6个坡角(±6°,±12°,±20°)及水平地面行走的下肢运动学及动力学数据,并对特征时刻数据进行单因素重复测量方差分析.结果:随坡角增大,步速和步频显著减少(P≤0.05);上坡行走时,随坡角增大,髋关节角度各特征时刻屈曲程度显著增加(P≤0.05),踝关节角度特征时刻(AA1、AA2)背屈程度显著增加(P≤0.05),髋关节伸力矩(HM1)及持续时间(HM2)显著增加(P≤0.05),踝关节各特征时刻跖屈力矩显著增加(P≤0.05);下坡行走时,随坡角增大,髋关节屈伸幅度显著减少(P≤0.05),膝关节特征时刻(KA2、KA3)屈曲幅度显著增大(P≤0.05),踝关节特征时刻(AA2、AA3)屈伸幅度显著增大(P≤0.05),膝关节伸力矩(KM2、KM3、KM4)显著增加(P≤0.05).结论:自选速度行走时步长步速与坡角之间为倒U型关系,不同坡角的上坡、下坡行走与平地行走之间通过不同控制策略来进行;上坡行走主要以增加下肢输出功率的推进为主,下坡行走主要以保持身体稳定性为主,坡角为±6°时不同策略的改变就已经产生.

PURPOSE: To examine the effects of Hoffman-reflex (H-reflex) and foot sole sensitivity on low extremity kinematics in people with peripheral neuropathy (PN). METHODS: People who are more (MST group, N = 13) and less (LST group, N = 10) sensitive to touch with physician-diagnosed PN were recruited for the experiment. Key outcome variables were H-reflex of the right soleus (SO), medial (MG) and lateral (LG) gastrocnemius muscles during standing, 6-minute walk distance (6MWD), duration of the timed up-and-go test (TUG), range of motion of the right hip, knee and ankle joints in the sagittal plane during walking on the treadmill, and three pairs (hip-knee, hip-ankle, and knee-ankle) of continuous relative phase variabilities (CPRv) used to evaluate lower extremity joint coordination. Statistically, the difference between LST and MST was examined using an independent sample T-test with p-value and effect size (Cohen’s d). RESULTS: NO significant differences in H-reflex, both H/M ratio and H-index detected between the two groups. The LST group walk shorter distances in the 6MWD test (380.4 ± 52.7 vs. 463.5 ± 47.6 m, p = .001, d = 1.64) and slower in the TUG test (9.0 ± 1.5 vs. 7.2 ± 1.1 s, p = .003, d = 1.38). The range of motion of the right hip, knee, and ankle of LST group were significantly less than that of the MST group (27.1 ± 6.6 vs. 34.6 ± 4.3 deg., p = .006, d = 1.35; 43.7 ± 13.8 vs. 58.0 ± 5.7 deg., p = .003, d = 1.34; and 17.0 ± 5.2 vs. 23.5 ± 6.3 deg., p = .015, d = 1.12). The LST group showed a greater amount of CRPv than the MST group (31.0 ± 10.4 vs. 21.4 ± 6.6, p = .013, d = 1.11) with no differences observed in the other two sets of CRPv values. A significant positive linear correlation was observed for the LST group between the range ankle range of motion and the H-index of LG (r = .681, p = .044). CONCLUSION: The deficits of foot sole sensitivity led to the decrease of range of motion and functional gait, and increased hip-ankle coordination variability during walking. The tactile sensation plays a role in regulating the range of motion of the lower extremity. Interestingly, with the increase of the nerve conduction velocity, the range of motion of the lower extremity increases accordingly. Thus, the lower threshold of tactile sensation in conjunction with faster proprioceptive feedback contributes to an increased range of motion and faster walking speed.