太极拳特定动作下股内侧肌和股外侧肌表面肌电特征的研究

目的 研究太极拳特定动作中股内侧肌(VMO)和股外侧肌(VL)的肌纤维募集情况.方法 收集15名健康志愿者在维持5个太极拳定势(白鹤亮翅、金鸡独立、搂膝拗步、十字手、仆步)时VL、VMO的表面肌电信号,比较平均肌电值(AEMG)、平均功率频率(MPF)、中位频率(MF)、零点通过率(ZCR).结果 维持白鹤亮翅、金鸡独立时,其支撑脚VMO、VL的所有指标均无显著性差异;维持搂膝拗步、十字手、仆步时,其支撑脚VL的AEMG、MFC、ZCR、MF均小于VMO(P<0.05);与股四头肌的最大随意收缩负荷相比,所测试的动作下,肌肉负荷属于中小负荷,并且能募集到更多的慢肌纤维.结论 进行太极拳运动时,肌肉负荷较小,并且能募集到更多的慢肌纤维;某些太极拳动作下,VMO可以较多地募集到肌纤维.     

运动疗法对膝关节置换术后关节功能恢复的效果

目的:探讨主动运动和被动运动对人工全膝关节置换(TKA)术后2周膝关节功能恢复的效果。方法:选择我院2014年12月~2015年4月收治的60例骨性关节炎患者,将患者随机等分为主动运动组和被动运动组,主动运动组康复锻炼采用踝泵训练、股四头肌收缩训练、直腿抬高训练、弯腿训练、屈膝训练、站立行走训练及上下台阶训练。被动运动组行CPM机辅助训练,CPM机角度从30°开始,之后每天增加10°,伸膝屈膝完成一个动作45 s,每次30 min,每天2次。采用美国膝关节外科学会评定标准(KSS),对两组患者人工膝关节置换术后康复训练2周膝关节功能进行临床疗效评定。结果:主动运动组人工全膝置换术后2周膝关节的活动度、膝关节伸膝、屈膝肌群的肌力、膝关节稳定性改善程度优于被动运动组,两组比较差异有统计学意义(P0.05)。结论:主动运动更有利于患者膝关节活动度、膝关节伸肌、屈肌肌群的肌力、膝关节稳定性改善。     

不同负荷运动中下肢肌表面肌电图的变化

背景：尝试应用曲线拟合分析方法对表面肌电图进行分析和研究国内外尚处于起步阶段,将其应用于功率自行车运动至疲劳的研究鲜见报道。目的：探讨功率自行车不同负荷运动中下肢肌中值频率值的变化特征和规律,分析肌肉疲劳拟合曲线的特点及其影响肌肉疲劳的相关因素。方法：受试者为苏州大学体育学院8名男性青年,利用MONARK功率自行车,对受试者在不同负荷以及不同踏蹬频率下进行测试至疲劳,同时对股直肌、股外侧肌、股内侧肌、胫骨前肌、腓肠肌内侧头和腓肠肌外侧头进行表面肌电信号的采集与记录。分析中值频率指标的变化,并用minitab.15统计软件,按照在F检验的统计学差异有非常显著性意义（P〈0．001）的前提下,选取判定系数序最大,偏差的平方和最小的原则,对实验结果进行曲线优度拟合。结果与结论：①功率自行车150W运动时,肌纤维的募集形式由运动初始快肌纤维募集数量逐渐增多向慢肌纤维募集比例增高转变。②功率自行车300W运动时,肌纤维的募集形式从运动初期的快肌纤维募集为主逐渐向慢肌纤维募集比例增高转变。③功率自行车150W运动时,肌肉疲劳的拟合曲线均为三次项曲线,提示影响肌肉疲劳的主要因素有3个。300W运动时,肌肉疲劳的拟合曲线均为二次项曲线,提示影响肌肉疲劳的主要因素有2个。     

两种主动直腿抬高动作相关肌群募集模式的分析

目的比较两种主动直腿抬高(ASLR)动作的募集程度,并探讨相关肌群的募集模式。方法 2018年6月至10月,选取11例健康受试者,记录动作A(连贯动作)和动作B(滞空10 s)单侧股直肌以及双侧腹直肌、腹外斜肌、腹内斜肌的表面肌电(sEMG)信号,并分析这些肌肉最大自主等长收缩(MVIC)时的募集程度(%MVIC)。结果在动作A中,同侧腹内斜肌和腹外斜肌募集程度大于对侧(t 2.549, P 0.05);在动作B中,同侧的腹内斜肌、腹外斜肌和腹直肌募集程度大于对侧(t 2.240, P 0.05);动作A时,双侧腹内斜肌和股直肌募集率更多(t 3.549, P 0.05)。结论两种ASLR动作都表现为同侧优势激活模式;在不同ASLR动作中,神经肌肉系统采取不同的运动控制策略。     

肘关节屈伸肌群等速肌力测试与分析

目的:通过测量肘关节屈肌、伸肌群在不同收缩方式、不同运动速度、不同关节角度时力矩的变化情况,以期用肘关节等速测试的力矩指标米评定肘关节及其周围肌群的功能状态.方法:实验于2006-09在江苏省级机关医院完成.测量了南京体育学院运动系20名男生肘关节屈、伸肌群在等速向心不同运动速度下的肌力参数,向心收缩各测2个不同速度:60(°)/s、120(°)/s.前者每次重复5次,间歇约1 min;后者每次重复10次,间歇约1 min.取最大力矩、最大力矩角度及上述角度的力矩.观察不同速度下屈、伸肌肌峰力矩比较;不同速度下屈伸肌肌峰力矩的相关分析;不同速度下肌峰力矩角度的比较分析;等速向心收缩的加速、放松时间.结果:①肘关节屈伸肌群等速向心收缩时随着关节给定运动速度的加快,屈肌峰力矩从34.5 N·m减到28.5 N·m,伸肌峰力矩从43.0减到32.7 N·m.②随速度增快,屈肘峰力矩角度增大,伸肘峰力矩角度减小.③当给定运动速度加快时,肘关节屈伸肌的加速时间均随之增长,伸肌的加速时间比屈肌的加速时间短.④前臂与上臂长的比值和伸60(°)/s的峰力矩角度呈负相关.结论:不同速度下,对于肘关节屈肌群而言,屈伸肌比值、肱二头肌、肱肌、肱桡肌、桡侧腕长伸肌和旋前圆肌的加速时间与肱三头肌、肘肌的放松时间、对于屈肌的肌峰力矩具有重要作用,而肱三头肌、肘肌的加速时间与肱二头肌、肱肌、肱桡肌、桡侧腕长伸肌和旋前圆肌的放松时间对于伸肌的肌峰力矩具有重要作用.     

不同下肢体位振动对脑卒中患者下肢肌力及运动功能的影响

目的:探讨不同下肢体位振动治疗对脑卒中患者下肢功能和肌力的影响。方法:选择2018年7月至2019年8月于西南医科大学附属医院康复科收治的72例脑卒中患者,随机分为对照组、迈步振动组、后伸振动组、屈膝运动振动组,每组18例。三种振动治疗组在对照组基础上增加不同体位下的振动治疗,20min/次,1次/天,5天/周,持续6周。在基线、振动训练6周、随访12周时评估Fugl-Meyer量表下肢部分、起立-行走计时试验(TUG)、膝屈伸肌等速肌力峰力矩。结果:共66例患者完成该研究。各组6周及12周时Fugl-Meyer、TUG、双侧伸膝及屈膝肌峰力矩均较治疗前有显著性差异(P<0.05)。三种振动治疗组6周及12周时Fugl-Meyer、TUG、患侧伸膝肌峰力矩较对照组有显著性差异(P<0.05)。屈膝运动振动组6周时患侧伸膝肌峰力矩显著高于迈步组及后伸组(P<0.05)。四组健侧伸膝肌、双侧屈膝肌峰力矩在6周与12周差异不具备显著性意义(P>0.05)。结论:全身振动疗法能提高脑卒中患者患侧膝关节伸肌肌力与下肢整体运动功能,且屈膝运动振动治疗在提高患侧伸肌力量方面更具优势。     

膝关节角度对屈伸肌共同收缩及伸膝力矩的影响

目的 应用表面电极肌电图（EMG）测量膝关节在不同角度做开放链最大等长伸膝时屈膝肌的共同兴奋能力，比较不同角度膝屈伸肌的共同兴奋水平。方法 12名健康在校大学生参与测试。每名受试者在Cybex测试仪上髋关节屈曲90°，单侧膝关节分别于屈膝10，60和90°时各做1组开放链的最大等长伸膝动作。使用表面电极EMG测量每次膝关节伸展时股四头肌与胭绳肌的电信号。在每次伸膝的同时用cy—bex测量股四头肌的最大伸膝力矩。结果所有角度下股四头肌的最大等长收缩均伴胭绳肌的共同兴奋。平均最大伸膝力矩出现在屈膝60°（P〈0．05）。结论膝关节在屈膝60°时可产生最大等长伸膝力矩，开放链的伸膝肌等长收缩伴有屈膝肌的共同兴奋。     

躯干等速向心屈伸运动时屈伸肌肌力的变化:脊柱最易受损伤的角度范围

背景:目前对躯干肌肌力的研究主要集中于腰痛患者肌力变化方面,而对脊柱容易损伤的角度范围的研究不多.目的:探讨躯干等速向心屈伸动作时屈伸肌肌力变化的特征及脊柱最容易损伤的角度范围.方法:苏州大学2005/2007级研究生,健康男性14名,自愿参加测试.选用瑞士产CON-TREX人体肌力评估和训练系统,测量受试者等速向心运动时的屈伸肌肌力及脊柱角度.测试速度分别为30,60,90,120,180(°)/s,每种速度下,受试者尽自己最大力量屈伸躯干4次,组间休息5 min.主要观察:①受试者躯干运动的关节活动范围.②等速向心运动屈伸峰值力矩、屈伸肌峰值力矩比及到达峰值力矩的平均角度的变化.③等速向心运动屈伸肌总功、平均功率.结果与结论:①等速向心运动时,伸肌的峰值力矩值随角速度的增加而减少(P＜0.05),屈肌峰值力矩值未见规律性的变化;屈、伸肌的峰值力矩比随角速度的加快而增大,但差异无显著性意义(P＞0.05).②慢速等速向心运动时,不同角速度下屈、伸肌到达峰值力矩角度分布离散,30(°)/s时为-48.56°,90(°)/s时为-46.18°;快速运动时,屈、伸肌出现最大峰值力矩角度基本接近,120(°)/s时分别为-48.71°,-51.61°, 180(°)/s分别一54.86,-53.11°.⑨等速向心运动时,在不同角速度下,屈、伸肌的总功均随角速度的增加而减少,伸肌总功大于屈肌,伸肌总功的变化差异有显著性意义(P＜0.05);屈、伸肌的平均功率随角速度的增加呈线性上升,屈肌平均功率始终小于伸肌(P＜0.01).结果提示:①等速向心运动时,躯干屈伸肌群的肌力随角速度的增加而减小,躯干在慢速屈伸运动时稳定性较好.②快速等速向心运动时,突受外力打击后容易引起肌肉损伤和脊柱不稳.③等速运动时屈伸肌做功随运动速度下降而降低,但肌肉的爆发力随运动速度的增快而加大.     

青年男女膝关节屈伸肌群达到峰值力矩时关节角度变化规律的等速肌力测试

背景:人体各关节灵活程度不同,但屈伸运动都是具备的,在日常活动当中,屈伸运动也是最为常见的,但关节屈伸时在何角度产生的力矩是最大的昵?目的:掌握膝关节屈伸时发挥最大肌力的关节角度,为运动健身、训练提供理论指导.设计、时间及地点:对比观察,试验于2008-04/06在郑州大学体育学院实验室进行.对象:自愿参加测试的大学生男女各30名.方法:测试仪器使用澳大利亚产Kinitech等速肌力测试系统,按照Kinitech等速肌力测试系统手册要求对参试者膝关节进行固定并测试,3种测试速度为慢速60(°)/s中速120(°)/s和快速240 (°)/s.主要观察指标:膝关节屈伸肌群的峰值力矩、达到峰值力矩时关节角度.结果:在速度为60(°)/s时,男女左屈肌小于右屈肌达到峰值力矩的关节角度,且左伸肌小于右伸肌;男子右屈肌达到峰值力矩的关节角度大于左屈肌,且女子与男子相同.在速度为120(°)/s时,男子屈伸肌达到峰值力矩的关节角度差异不显著,女子右伸肌达到峰值力矩的关节角度大于左伸肌.在速度为240 (°)/s时,男子左屈肌达到峰值力矩的关节角度大于右屈肌,而左伸肌和右伸肌差异不存在显著性.女子左右屈伸肌差异也不存在显著性.结论:自然发育下人体存在优势腿,在不同速度下达到峰值力矩的关节角度有所不同,在日常运动健身时尽可能的全面训练,使屈伸肌群得到全面发展.     

关节镜下半腱肌和股薄肌双束重建前交叉韧带后膝关节本体感觉的功能评定

背景;前交叉韧带重建是前交叉韧带损伤的主要治疗方案,近年来,前交叉韧带重建后膝关节本体感觉的研究进展迅速.目的:对关节镜下半腱肌和股薄肌双束重建膝关节前交叉韧带后的本体感觉进行评定.设计、时间及地点:病例对照,于2007-08/2008-06在潍坊医学院附属医院骨科完成.对象:用14例关节镜下半腱肌和股薄肌双束重建前交叉韧带的男性患者作为试验组和14例健康男性作为对照组.方法:所有患者前交叉韧带重建都经过12个月神经肌肉康复训练,通过在负重的条件下屈伸运动重现设定的角度来评定关节的位置觉,测试健康的受试者和患者的双膝伸膝运动、屈膝运动关节位置重现偏差.主要观察指标:患者的患侧膝关节、健侧膝关节和健康受试者膝关节在伸膝运动和屈膝运动时主动关节位置重现测试的比较.结果:患者患膝与健膝关节位置重现偏差、患者侧膝与健康者关节位置重现偏差及患者健膝与健康者关节位置重现偏差比较,差异均无显著性意义(P0.05).结论:前交叉韧带重建后12个月的患膝和健康膝关节在承重条件下的位置觉无明显差别.     

Relationship between wire EMG activity,muscle length,and torque of the hamstrings

OBJECTIVE: To determine the effect of change of muscle length on the torque and wire electromyographic activity of six knee flexor muscles. DESIGN: Maximum isometric knee flexion torque and wire EMG data were collected at nine different positions. BACKGROUND: In vivo EMG-length-tension relationship is difficult to determine because of the interaction between muscle length and moment arm. The study of two-joint muscles allows the change of muscle length at one joint while preserving stable mechanical relationships at the other. This model facilitates understanding of length-tension and EMG-length relationship in vivo. METHODS: Nineteen subjects performed maximum isometric knee flexion contraction at nine positions of varying hip and knee angles. Wire EMG activity was recorded from semitendionsus, semimembranosus, long and short head of the biceps femoris, gracilis and sartorious muscles. RESULTS: As the two-joint hamstrings were lengthened, torque was significantly increased. Maximum isometric torque ranged from 257 to 716 kg cm. The ratio of the torque values to EMG activity of all muscles was increased at longer muscle lengths. A change in the muscle length of the two-joint hamstrings did not produce a consistent change of EMG activity. The short head of the biceps femoris and sartorius muscles increased their activity as the angle of knee flexion increased. CONCLUSIONS: Maximum torque of knee flexion occurs at the most lengthened position of the hamstrings. EMG activity did not consistently change with the change in muscle length. RELEVANCE: Understanding in vivo length-tension relationship and associated EMG activity is important for designing rehabilitation protocols, tendon lengthening and transfer and interpretation of EMG data.     

Gender and fatigue have influence on knee joint control strategies during landing

Background

Gender and fatigue are thought to affect the anterior cruciate ligament injury risk. In spite of much effort, the influence of these factors on knee joint biomechanics is still under discussion. The purpose of this study was to investigate kinematics, kinetics, and active muscle control strategies of the knee joint across gender in fatigue conditions during a landing task.

Methods

Thirteen females and thirteen males performed two-legged landings before and after a closed kinetic chain exercise protocol. Knee joint kinematics and vertical ground reaction forces were assessed as well as electromyography of the quadriceps, hamstring, and gastrocnemius muscles.

Findings

Females landed with increased knee flexion velocities (P < 0.001) and knee joint abduction angles (P < 0.01). Compared to males, females also showed different muscle activation patterns such as a delayed activation of the lateral hamstring (P < 0.05) and the m. vastus lateralis (P < 0.05) during the preparatory phase of the landing. Fatigue led to a reduced pre-activation of the medial and lateral hamstrings (P < 0.05 and P < 0.001) and the gastrocnemius muscle (P < 0.05) both in males and females.

Interpretation

The gender differences in knee flexion velocity, abduction angle, and muscle activation suggest that females and males possess different neuromuscular strategies to control the knee joint during dynamic landing movements. These differences as well as decreased hamstring and gastrocnemius muscle activity, due to fatigue, provide evidence for different knee joint control in females as well as in fatigued conditions.     

脑卒中偏瘫患者健侧膝关节的运动学特征观察

目的:观察脑卒中偏瘫患者在异常步态时健侧膝关节的运动情况,为临床康复评定和治疗提供依据。方法:运用Opti-Knee膝关节运动功能参数检测仪对符合纳入标准的60例脑卒中偏瘫患者作为观察组进行步态分析,与其基本情况相匹配的健康者60例作为对照组,进行步行时健侧膝关节运动分析。评价2组间在步行中健侧膝关节6个自由度(屈伸、内外旋、内外翻、前后位移、上下位移、内外位移)的运动角度以及支撑期的最大伸角和摆动期的最大屈角的变化。结果:观察组脑卒中患者的健侧膝关节活动范围与对照组比较,其健侧膝的屈伸角、内外旋、内外翻的活动范围均显著小于正常组(P<0.01,P<0.05);与对照组比较,观察组脑卒中患者健侧膝的最大伸角和最大屈角均显著减小(P<0.05,0.01)。结论:通过Opti-Knee膝关节运动功能参数检测仪分析偏瘫患者健侧膝关节活动范围,可以帮助确定偏瘫步态基本特征,为下一步的康复训练提供临床依据。     

Comparison of Lower Limb Muscle Activity during Eccentric and Concentric Exercises in Runners with Achilles Tendinopathy

[Purpose] This study aimed to identify changes in muscle activation by comparing muscle activities of the affected side (AS) and non-affected side (NAS) during eccentric and concentric exercises in runners with unilateral Achilles tendinopathy. [Subjects] The study included 18 participants consisting of men and women with chronic Achilles tendinopathy in a single leg who had more than 1 year of running experience. [Methods] All subjects performed concentric and eccentric exercise with the Achilles tendon moving from full plantar flexion to full dorsiflexion for 8 seconds, and electromyography data was obtained. [Results] All muscles examined showed a significant increase in %maximal voluntary contraction (MVC) with concentric exercise compared with eccentric exercise. Compared with the NAS, the AS showed significant increases in %MVC of the rectus femoris, tibialis anterior, and lateral gastrocnemius. All interaction effects of exercise methods and injuries showed statistically significant changes. [Conclusion] Runners with Achilles tendinopathy show increases in medial gastrocnemius activity when performing eccentric exercise.Key words: Achilles tendinopathy, Eccentric exercise, Electromyography     

Tibiofemoral joint forces during maximal isokinetic eccentric and concentric efforts of the knee flexors

OBJECTIVE: The examination of muscular and tibiofemoral joint forces during maximal efforts of the knee flexors. DESIGN: The muscular and tibiofemoral joint knee forces during eccentric and concentric isokinetic efforts of the knee flexors were determined using a two-dimensional mathematical model. BACKGROUND: The examination of joint and muscle loading during isokinetic movements is important for the determination of safety of this exercise. METHODS: Ten healthy males performed three maximal isokinetic concentric and eccentric efforts of the knee flexors at angular velocities of 30 degrees s(-1), 90 degrees s(-1), 120 degrees s(-1) and 150 degrees s(-1). The muscular, tibiofemoral shear and compressive joint forces were determined using a two-dimensional model. RESULTS: The maximum muscular force ranged from 3.44 (Standard deviation, 1.32) times body weight to 6.19 (1.78) times body weight. The tibiofemoral compressive force ranged from 2.62 (1.17) times body weight to 5.89 (1.99) times body weight occurring at angles ranging from 0 degrees to 40 degrees of knee flexion. The posterior shear force ranged from 2.61 (1.33) times body weight to 3.89 (1.62) times body weight and was observed at angles ranging from 50 degrees to 80 degrees of knee flexion. Two-way analysis of variance designs indicated significant effects of type of muscle action and angular velocity on muscle and compressive forces (P<0.05). In contrast, the shear force was not affected by the type of muscle action or the angular velocity (P>0.05). CONCLUSIONS: Isokinetic efforts of the knee flexors induce high tibiofemoral joint forces, especially during high-speed eccentric tests.     

Effects of trunk anterior tilt and knee joint flexion angle changes on muscle activity in the lower limb muscles

[Purpose] We examined the effects of trunk anterior tilt angle (TA) and knee flexion angle (KA) on lower limb muscle activity. [Participants and Methods] Twenty-eight healthy male participants (age, 24.7 ± 4.7 years) performed nine standing tasks with different TA and KA. The participants were instructed to remain still during each task. The nine standing tasks were randomly performed while measurements of muscle activity were obtained for seven muscles: gluteus maximus (GMAX), medial hamstrings (MH), lateral hamstrings (LH), rectus femoris (RF), vastus lateralis (VL), medial gastrocnemius (MG), and soleus (SOL). The activities of these muscles were normalized using isometric grade 3 of the manual muscle testing (isoMMT3). The intra-rater reliability for the mean values of the muscle activities measured with the isoMMT3 (intra-class correlation coefficient with 95% confidence interval) was confirmed using equation ICC (1,3). [Results] GMAX, MH, LH, RF, and MG were affected by both TA and KA, whereas VL was affected by KA, and SOL was affected by TA. [Conclusion] Our findings may facilitate a better understanding of the changes in muscle activity of the lower limb muscles due to differences in TA and KA.Key words: Electromyography, Muscle activation, Standing position     

Patellar tendon load in different types of eccentric squats

BACKGROUND: Differences in mechanical loading of the patellar tendon have been suggested as a reason for varying effects in rehabilitation of patellar tendinopathy using different eccentric squat exercises and devices. The aim was to characterize the magnitude and pattern of mechanical load at the knee and on the patellar tendon during four types of eccentric squat. METHODS: Subjects performed squats with a submaximal free weight and with maximal effort in a device for eccentric overloading (Bromsman), on a decline board and horizontal surface. Kinematics was recorded with a motion-capture system, reaction forces with force plates, and electromyography from three leg muscles with surface electrodes. Inverse dynamics was used to calculate knee joint kinetics. FINDINGS: Eccentric work, mean and peak patellar tendon force, and angle at peak force were greater (25-30%) for squats on decline board compared to horizontal surface with free weight, but not in Bromsman. Higher knee load forces (60-80%), but not work, were observed with Bromsman than free weight. Angular excursions at the knee and ankle were larger with decline board, particularly with free weight, and smaller in Bromsman than with free weight. Mean electromyography was greater on a decline board for gastrocnemius (13%) and vastus medialis (6%) with free weight, but in Bromsman only for gastrocnemius (7%). INTERPRETATION: The results demonstrated clear differences in the biomechanical loading on the knee during different squat exercises. Quantification of such differences provides information that could be used to explain differences in rehabilitation effects as well as in designing more optimal rehabilitation exercises for patellar tendinopathy.     

Passive knee muscle moment arms measured in vivo with MRI

Objective. To determine moment arm lengths from seven knee muscles and the patellar tendon. The knee muscles were the biceps femoris, semitendinosus, semimembranosus, gracilis, sartorius, and the lateral and medial gastrocnemius muscles.

Design. The moment arms were calculated based on MRI measurements.

Background. Moment arm lengths of different muscles with respect to the joint centre of rotation (CR) or the centre of the contact point between joint surfaces are necessary basic data for biomechanical models predicting joint load.

Methods. Ten male and seven female subjects participated. Using a 1.5 Tesla magnetic resonance imaging system, 3-dimensional coordinates of relevant points were recorded from a 3-D volume reconstruction of the right knee at knee flexion angles of 0, 30 and 60 °. Muscular moment arms were calculated in both the sagittal and frontal planes. The recordings were all made during passive mode, which means that no muscular contraction was performed.

Results. All muscles except the lateral gastrocnemius showed statistically significant differences (P < 0.05) of moment arm lengths between gender in the frontal plane. All muscles except biceps femoris and sartorius showed significant differences (P < 0.05) of moment arm lengths between gender in the sagittal plane. Most muscles also showed a linear or quadratic trend of changing moment arms with varying knee angle.

Conclusions. Our results indicate that for most biomechanical analyses involving knee muscles, gender- and angle-specific moment arms should be used.     

Plaidoyer pour une prise en charge précoce des ischiojambiers après DIDT

After ACL surgery, the goal of rehabilitation programme is to develop hamstrings (HT) muscle’s strength. These muscles act against the anterior drawer and are involved in the rotational control of the knee. With a graft using HT (semi-tendinous and gracilis), many authors recommend to start the HT’s exercices only after three to six weeks postoperatively. Literature’s analysis shows that the HT strength’s recovery is incomplete and hard to realize; so copying the rehabilitation programme after tendon and muscle’s injuries, we recommend an early sub-maximal eccentric work of the HT on isokinetic system at low speed (from 5° to 15°/sec) after ten days post-surgery for the flexor knee muscles, and after thirty days post-surgery for the rotational muscles. This kind of work can stimulate the healing and the reintegration of the HT. After three months postoperatively, an isokinetic assessment must confirm the return to footing; furthermore a physical training must allow a return to all sportive activities.     

The effects on sensorimotor performance and balance with Tai Chi training

OBJECTIVES: To compare the effects of short-term and long-term Tai Chi training on the sensorimotor and balance performance of able-bodied subjects. DESIGN: A nonrandomized cross-sectional controlled trial. SETTING: Sport laboratory. PARTICIPANTS: Forty-eight healthy subjects, 16 with 3 months of experience in Tai Chi training, 16 with 1 to 3 years of experience in Tai Chi training, and 16 with no experience in Tai Chi training. INTERVENTION: Experimental. MAIN OUTCOME MEASURES: The reflex contraction latencies (reaction time) of medial hamstrings and gastrocnemius after perturbation, the active knee joint angle-repositioning error, and the balance time on a tilt board were measured and analyzed with 1-way analysis of covariance. Significant results were further analyzed with post hoc linear contrasts. RESULTS: Long-term Tai Chi practitioners had a significantly faster reflex reaction time in hamstrings (P<.000) and gastrocnemius (P=.043) muscles and a longer balance time on a tilt board (P<.000) than short-term Tai Chi practitioners and nonpractitioners. Both long- and short-term Tai Chi practitioners had significantly less knee joint angle-repositioning error than nonpractitioners (P=.001 and P=.027, respectively). CONCLUSIONS: Tai Chi training of more than 1 year might have the benefits of faster hamstrings and gastrocnemius reflex reaction and improved knee joint position sense (JPS). These changes might be associated with an improved dynamic standing balance. Better knee JPS was shown in subjects with 3 months of Tai Chi practice, but this had not led to a significant improvement in balance.