应用等速肌力测试评价膝前交叉韧带断裂重建术后康复的效果

目的:采用等速肌力测试系统测试前交叉韧带(ACL)断裂患者在重建术前、术后的肌肉力量,评价有、无严格的康复训练计划对患者康复效果的影响。方法:采用美国产Biodex System 3多关节等速肌力测试系统,以60°/s、120°/s两种速度测定67例膝关节前交叉韧带断裂及韧带重建术后6个月、12个月患者的股四头肌和腘绳肌肌力,包括峰力矩(PT)、峰力矩/体重比值(PT/BW)、总功(TW)、平均峰力矩(AVG PT)。将其中遵医嘱进行康复训练的24人作为康复训练组,另外无严格康复训练计划、自主活动的43人作为未康复训练组。结果:手术前患膝屈、伸肌群的PT、PT/BW、TW、AVG PT较健侧均显著降低;ACL重建术后6个月、12个月,两组患者股四头肌和腘绳肌肌力均较术前有所提高,其中未康复训练组患侧股四头肌肌力恢复至健侧70%左右,腘绳肌肌力恢复至健侧75%,康复训练组股四头肌和腘绳肌肌力分别恢复至健侧的80%和85%左右,高于未康复训练组,但与健侧相比仍有差距。结论:康复训练对ACL重建术后股四头肌和腘绳肌的肌力恢复有明显的作用。等速肌力测试是评价前交叉韧带重建术后康复效果的有效手段。     

中国女子篮球运动员膝关节等速肌力测试分析

目的:了解中国国家女子篮球队运动员膝关节等速肌力特征。方法:选用IsoMed 2000等速测试系统,采用60°/s、180°/s、240°/s三种角速度,测试18名中国女篮国家队运动员膝关节等速肌力。根据场上位置将运动员分为三组:后卫组7人(1、2号位),前锋组6人(3、4号位),中锋组5人(5号位),比较分析三组运动员的测试结果。结果:(1)女篮运动员双侧膝关节慢速测试时(60°/s)屈伸肌峰力矩(PT)显著高于快速测试(180°/s,240°/s),膝关节屈伸肌峰力矩比值(H/Q)随测试速度增加递增,左右膝H/Q无显著性差异。(2)慢速测试时(60°/s),左右膝关节峰力矩、峰力矩/体重比值、平均功率、H/Q无显著差异。(3)快速测试(240°/s)时,左膝屈肌PT、峰力矩/体重比值(PT/BW)显著高于右膝。180°/s测试时,左膝屈肌平均功率显著高于右膝。(4)60°/s测试时,后卫、前锋、中锋运动员PT、PT/BW组间比较无显著性差别。180°/s测试时,后卫运动员左膝屈肌PT与前锋、中锋运动员比较有显著性差异(P=0.02),各组间伸肌PT未见显著差异。240°/s测试时,后卫运动员右膝屈、伸肌PT/BW和中锋运动员比较均存在显著差异;后卫、前锋、中锋三组运动员平均功率、H/Q、总功与峰值功率组间比较均无显著性差别。结论:(1)女篮运动员快速测试(240°/s)时左膝屈肌力量强于右膝,反映快速运动时左右膝关节肌力不平衡。(2)不同场上位置女篮运动员膝关节等速肌力快速测试结果有差异性,提示力量训练应根据场上位置进行特异性训练。(3)女篮运动员需加强屈肌快速力量训练,以提高H/Q,预防膝关节损伤。     

膝关节损伤后远期肌力改变的分析

目的 :分析膝关节韧带、半月板等损伤后股四头肌、绳肌远期肌力改变的情况 ,以探讨损伤后远期肌力改变与肌肉收缩类型的关系、向心收缩 /离心收缩比值和拮抗肌比值等反映膝关节稳定性指标的变化、优势下肢膝关节损伤的特点及肌力改变与损伤时间的相关关系。方法 :应用Kin-Com等速测试装置分别测定 3 8例膝关节损伤后受试者等长收缩肌力峰值、60°/sec和 1 80°/sec角速度下向心收缩、离心收缩力矩峰值。结果 :(1 )损伤侧与非损伤侧股四头肌在不同测试条件下远期肌力存在显著差异 (P <0 0 5 ) ,同名肌群肌力缺失百分比 >1 0 % ;(2 )损伤侧与非损伤侧绳肌在不同测试条件下远期肌力无显著性差异 (P >0 0 5 ) ;(3 )损伤侧膝关节以 60°/sec角速度向心收缩、离心收缩时远期肌力减退程度显著高于等长收缩时远期肌力的减退程度 (P <0 0 5 ) ;(4 )等速测试时损伤侧与非损伤侧的向心收缩/离心收缩比值无显著差异 (P >0 0 5 ) ,且均 <1 0 0 % ;(5 )损伤侧膝关节拮抗肌比值范围为 5 0 %～ 80 % ;(6)优势下肢膝关节损伤患者股四头肌远期肌力减退程度显著高于非优势下肢膝关节损伤患者 (P <0 0 5 ) ;(7)等长收缩、向心收缩、离心收缩远期肌力缺失百分比与损伤时间无显著相关关系 (P >0 0 5 )。结论 :膝关节     

21 d-6°头低位卧床期间运动训练对动态姿态平衡的影响

目的探讨21 d-6°头低位卧床和卧床运动训练对动态姿态平衡和控制功能的影响. 方法 10名健康男性青年被试者分为卧床对照组和卧床训练组,每组5人,卧床期间训练组每天进行2次、每次30 min逐级增加负荷的头低位功率自行车训练;分别于卧床前和卧床后21 d进行了动态姿态平衡和双膝等速肌力的测试. 结果与卧床前相比,对照组动态本体感觉得分和运动控制适应能力明显降低,双膝相对峰力矩明显降低,同时伴有腘绳肌与股四头肌峰力矩屈/伸比值的明显增加;训练组动态本体感觉得分和运动控制适应能力明显高于对照组,而腘绳肌与股四头肌峰力矩屈/伸比值无明显改变. 结论 21 d-6°头低位卧床运动训练能够明显改善卧床后动态姿态平衡及其动态运动适应功能.     

前十字韧带损伤后股四头肌腘绳肌等速肌力评价(附5例报告)

用Ｃｙｂｅｘ－６０００型等速测力系统对５例前十字韧带（ＡＣＬ）损伤后患者股四头肌绳肌肌肉功能进行评价。结果表明：患膝屈伸肌群峰力矩在６０°／ｓ、１２０°／ｓ和１８０°／ｓ时均较健侧明显降低；在１８０°／ｓ时，股四头肌绳肌的总作动量、平均功率和力矩加速能量亦显著下降；绳肌股四头肌峰力矩比值（Ｈ／Ｑ）较健侧略有增高，但患者间差异较大。废用性肌肉萎缩、关节不稳及关节源性肌肉抑制可能是导致肌肉功能下降的重要原因。ＡＣＬ损伤后应强调患膝肌力训练，以增强关节稳定性，预防或延迟膝关节骨关节炎的发生；并把Ｈ／Ｑ作为肌力训练中一个评价和监测指标。     

青年军人腰椎间盘突出症患者下肢肌力等速测试分析

采用ＣＹＢＥＸ６０００型等速测力系统,对腰椎间盘突出症引起单侧下肢受累的１９名男性青年军人患者,进行双下肢膝屈伸肌力的对照测试,结果表明：与健肢相比,患肢在６０°／ｓ速度测试时,腘绳肌和股四头肌肌力分别平均下降了４５％和３１％,在１８°／ｓ时分别下降了５７％与３５％。提示患肢屈肌力下降明显,治疗康复期内应加强腘绳肌群锻炼。     

优秀击剑运动员下肢三关节等速肌力测试分析

目的:研究我国优秀击剑运动员下肢髋、膝、踝三关节肌群等速肌力表现,找出薄弱肌群。方法:国家击剑队备战2008年奥运会重点队员26名,男女各13名,年龄23.1±2.36岁。在60°/s、240°/s速度下测定运动员双侧下肢髋、膝、踝屈伸肌群等速向心峰力矩。结果发现:(1)髋关节:在240°/s下双侧伸肌峰力矩均明显低于60°/s(P<0.05),60°/s和240°/s下双侧髋关节屈肌峰力矩无显著差异(P>0.05);男运动员两个速度下前腿伸肌峰力矩均显著高于后腿(P<0.05),女运动员无显著差异(P>0.05);两个速度下,运动员双腿屈伸肌峰力矩比值低于正常。(2)膝关节:60°/s时男运动员双腿屈伸肌峰力矩有显著差异(P<0.05),240°/s时双侧伸肌峰力矩有显著差异(P<0.05),女运动员两个速度下均无显著差异(P>0.05);60°/s时,女运动员前后腿屈伸肌峰力矩比值分别为0.56和0.54,男运动员分别为0.63和0.67;240/°s时男女前后腿屈伸肌峰力矩比值均在正常范围。(3)踝关节:60°/s时男运动员前腿踝关节屈伸肌峰力矩显著大于后腿(P<0.05),240°/s时无显著差异(P>0.05);两个速度下,女运动员踝关节屈伸肌峰力矩均无显著性差异(P>0.05);运动员踝关节屈伸峰力矩比值在两个速度下均低于正常。结论:优秀男子击剑运动员下肢关节等速肌力双侧不对称,女运动员不对称表现不明显;击剑运动员下肢薄弱肌群为后腿髋关节伸肌群、股后肌群、前腿股后肌群及踝关节背伸肌群。     

青年军人腰椎间盘突出症其下肢肌力等速测试分析

采用CYBEX6000型等速测力系统,对腰椎间盘突出症引起单侧下肢受累的17名男性青年军人患者,进行双下肢膝屈伸肌力的对照测试,结果表明患侧与腱侧相比,在60°/s速度测试时,绳肌和股四头肌分别平均下降了45%和31%,在180°/s时分别下降57%与35%。提示患肢屈肌力下降明显,治疗康复期内应加强绳肌群锻炼。     

不同级别男子跳高运动员髋关节屈伸峰力矩测试分析

目的:分析比较不同级别男子跳高运动员髋关节屈伸肌群向心收缩时峰力矩特点及差异。方法:采用德国ISOMED2000等速测试仪,对8名一级男子跳高运动员和8名二级男子跳高运动员髋关节肌群进行等速向心收缩测试,测试角速度120°/s,指标包括峰力矩、相对峰力矩(峰力矩/体重)、峰力矩出现角度。结果:一级跳高运动员摆动腿屈肌峰力矩和相对峰力矩显著大于二级运动员(P<0.01),起跳腿伸肌峰力矩和相对峰力矩显著大于二级运动员(P<0.05,P<0.01);一、二级运动员髋关节屈、伸肌群最大峰力矩时的角度均在85度左右。结果表明:一级运动员摆动腿向上摆腿力量和起跳腿伸髋力量大于二级运动员。     

耐力力量复合训练对新兵膝屈伸肌功能影响的等速测试研究

为探讨耐力力量复合训练对新兵膝屈伸肌功能的影响 ,选择 2 0名新兵进行为期 4周的耐力力量复合训练 ,训练前后采用Cybex 6 0 0 0型等速运动测试仪对新兵的膝屈伸肌肌力、肌爆发力及肌耐力进行等速测试并加以比较。结果显示 ,训练后双膝屈肌的峰力矩、力矩加速能和耐力比在不同测试速度 (6 0°/s ,180°/s)时有不同程度的提高 ,训练前后相比有显著性差异 (P <0 .0 5 ) ;双膝伸肌的TAE和ER值也有明显的提高 ;峰力矩H/Q值训练后均有提高 ,但训练前后无显著性差异 (P >0 .0 5 )。提示为期 4周的耐力力量复合训练可有效地发展双膝屈肌的肌力、肌爆发力和肌耐力 ,同时应加强力量训练的负荷以全面发展伸肌力量。     

Acute effects of static and dynamic stretching on leg flexor and extensor isokinetic strength in elite women athletes

The aim of this study was to explore the effects of static and dynamic stretching of the leg flexors and extensors on concentric and eccentric peak torque (PT) and electromyography (EMG) amplitude of the leg extensors and flexors in women athletes. Ten elite women athletes completed the following intervention protocol in a randomized order on separate days: (a) non‐stretching (control), (b) static stretching, and (c) dynamic stretching. Stretched muscles were the quadriceps and hamstring muscles. Before and after the stretching or control intervention, concentric and eccentric isokinetic PT and EMG activity of the leg extensors and flexors were measured at 60 and 180°/s. Concentric and eccentric quadriceps and hamstring muscle strength at both test speeds displayed a significant decrease following static stretching (P<0.01–0.001). In contrast, a significant increase was observed after dynamic stretching for these strength parameters (P<0.05–0.001). Parallel to this, normalized EMG amplitude parameters exhibited significant decreases following static (P<0.05–0.001) and significant increases following dynamic stretching (P<0.05–0.001) during quadriceps and hamstring muscle actions at both concentric and eccentric testing modes. Our findings suggest that dynamic stretching, as opposed to static or no stretching, may be an effective technique for enhancing muscle performance during the pre‐competition warm‐up routine in elite women athletes.     

Gains in flexibility related to measures of muscular performance: impact of flexibility on muscular performance.

OBJECTIVE: Studies that investigated possible correlations between flexibility and muscular performance are scarce in the literature. Therefore, the purpose of this study was to investigate the impact of a program of static stretching on the flexibility of the hamstrings and on muscular performance of the knee flexors and extensors. DESIGN: Pre-post experimental design. SETTING: University laboratory. PARTICIPANTS: Thirty subjects aged 22.8 +/- 4.9 years with bilaterally shortened hamstrings. INTERVENTION: Using a protocol that has been previously described, the intervention consisted of 30 sessions of static stretching, performed bilaterally five times a week for 6 weeks. MAIN OUTCOME MEASUREMENTS: Measures of knee range of motion and isokinetic muscular performance (peak torque, angle of peak torque, and work) of knee flexors and extensors at speeds of 60 and 300 degrees/s. RESULTS: After intervention, significant gains in measures of flexibility (P < 0.0001) were observed, with an average gain of the knee-extension angle of 12.6 degrees, ranging from -1.2 to 30.7 degrees. In addition, we found significant increases in the following parameters of muscular performance: angle of peak torque of hamstrings at 60 and 300 degrees/s (P < 0.0001 and 0.018) and for work at 60 and 300 degrees/s for knee flexors (P = 0.012 and 0.005) and for knee extensors (P < 0.0001). CONCLUSIONS: The intervention resulted in gains in measures of flexibility, and these gains had a positive impact on some parameters of muscular performance.     

Muscular strength changes in hospitalized anorexic patients after an eight week resistance training program

We investigated whether an eight week, light resistance program could increase the muscular strength of the knee and elbow extensors and flexors in a group of hospitalized anorexic patients compared to anorexic controls (AC) who did not participate in the training program, but received the same caloric intake, and non-anorexic exercisers (NAE) who undertook the resistance training program. After the resistance training program, the seven anorexic exercisers (AE) significantly increased the peak torque (PT) of their knee extensors (p < 0.001), flexors (p < 0.0001) and elbow flexors (p < 0.01). In comparison, the seven anorexic non-exercisers (anorexic controls, AC) and seven non-anorexic exercisers (NAE), who performed the same program, showed no significant increase in peak torque after the program (p > 0.05). The study has demonstrated that an eight week, light resistance program increases the knee and elbow strength of the hospitalized anorexic patients.     

Effects of aquatic resistance training on neuromuscular performance in healthy women

PURPOSE: The purpose of this study was to investigate the effects of a progressive 10-wk aquatic resistance training on neuromuscular performance and muscle mass of the knee extensors and flexors in healthy women. METHODS: Twenty-four healthy women (34.2 +/- 3.9 yr) were randomly assigned into aquatic exercise (N = 12) and control group (N = 12). Maximum knee extension and flexion torques were measured isometrically and at constant angular velocities of 60 degrees x s(-1) and 180 degrees x s(-1) (isokinetic) with simultaneous electromyography (EMG) recordings of the quadriceps and hamstrings. The lean muscle mass (LCSA) of the quadriceps and hamstring muscles was determined by computed tomography scanning. RESULTS: Significant interaction of group by time was observed in each of the measured parameters. The change in extension and flexion isometric/isokinetic torque varied between 8 and 13% and in EMGs between 10 and 27% in the exercise group. The change in the quadriceps LCSA of the exercise group was 4% and in hamstrings 5.5%. CONCLUSIONS: The results of the present study showed that 10 wk of progressive aquatic resistance training resulted in significant improvement in muscle torque of the knee extensors and flexors accompanied with proportional improvement in neural activation and with significant increase in the LCSA of the trained muscles. Aquatic training can be recommended for neuromuscular conditioning in healthy persons.     

Reliability of isokinetic normalized peak torque assessments for knee muscles in post-stroke hemiparesis

The purpose of this study was to establish test–retest reliability of measurement procedures for quantifying isokinetic concentric peak torque (PT) at the knee using normalization methods post-stroke. A second aim was to estimate the change required to show clinically significant improvements in knee muscles strength. The isokinetic normalized PT (NPT) values for the knee extensors and flexors were measured in each participant at two different angular velocities during two sessions 1 day apart. Thirty participants with mild to moderate hemiparesis after stroke who were able to walk were tested. The normalized PT measures for the knee muscles of the affected lower extremity were highly reliable (intraclass correlation coefficients ranged from 0.85 to 0.98; p < 0.05). Size of relative changes (the percent smallest real difference, SRD%) for extensors NPT (ranged from 22.35% to 25.68%) were lower than flexors NPT (ranged from 74.01% to 76.31%), indicating that the affected isokinetic knee flexors had more random variation than the knee extensors. This study supports the use of isokinetic dynamometers for the assessment of knee muscle strength in participants with chronic mild to moderate post-stroke hemiparesis and to measure clinical improvements. Established measurement error and smallest real differences in normalized PT will aid interpretation of real changes in muscle strength in this clinical population.     

Muscle fatigue during repetitive voluntary contractions: A comparison between children with cerebral palsy,typically developing children and young healthy adults

AimTo combine peak torque and EMG analyses to investigate the hypothesis that 1) children with cerebral palsy (CP) have lower muscle fatigability than typically developing children (TD) and whether 2) muscle fatigue correlates with muscle strength.MethodsSeven CP children, eight TD children and ten young healthy adults (YHA) performed an all-out fatigue test of 35 maximal concentric knee extension and flexion contractions on an isokinetic dynamometer. Angular velocity was set at 60°/s. Peak torque (PT) was determined per repetition and either normalized to bodyweight or maximum voluntary torque. Surface-EMG of quadriceps and hamstring muscles was measured to obtain changes in median frequency (EMG-mf) and smooth rectified EMG amplitude per contraction.ResultsDecline in PT differed between all groups for extensors and flexors, where YHA showed the largest decline and CP children the smallest decline over the course of the test. YHA showed a larger decline in EMG-mf of all quadriceps and hamstrings than TD and CP children, while TD children showed a larger decline in EMG-mf of m.rectus femoris and m.vastus lateralis than CP children.InterpretationResults confirm that children with CP show lower fatigability than TD children and that the lower fatigability coincides with lower maximal muscle strength.     

Effects and mechanisms of strength training in children

It has been demonstrated that strength training can be organized in children in a safe and effective way. However, there is limited data regarding its impact on muscle hypertrophy. This study investigated the effects of a high-intensity strength training (HIS) on knee extensor/flexor strength, countermovement (CMJ) jumping height, postural control, soft lean mass and muscle cross-sectional area (CSA) of the dominant leg in prepubertal children. Thirty-two children participated in this study and were assigned to an intervention (INT; N=17) or a control class ( N=15). The INT participated in 10 weeks of weight-machine based HIS integrated in physical education. Pre/post tests included the measurements of peak torque of the knee extensors/flexors at 60 and 180°/s, CMJ jumping height, postural sway, soft lean mass of the leg by bioelectrical impedance analysis, and CSA (m. quadriceps) by magnetic resonance imaging. HIS resulted in significant increases in knee extensor/flexor peak torque (60°/s and 180°/s). HIS did not produce significant changes in CMJ jumping height, postural sway, soft lean mass, and CSA. Although HIS was effective at increasing peak torque of the knee extensors/flexors in children, it was unable to affect muscle size. It appears that neural factors rather than muscle hypertrophy account for the observed strength gains in children.     

Muscle activation and torque development during maximal unilateral and bilateral isokinetic knee extensions

BACKGROUND: The aim of this study was to investigate whether or not a bilateral strength deficit occurs during bilateral (BL) velocity controlled dynamic knee extensions and if the neural control of the knee extensors and flexors is altered during homologous muscle BL efforts. METHODS: Twenty-eight healthy and habitually active subjects, 13 female and 15 male, performed maximal unilateral (UL) and BL isokinetic leg extensions at a velocity of 60 degrees.s-1 through a 90 degrees range of motion of the knee joint (90 to 180 degrees). Knee extension torque and electromyographic activity (EMG) of the quadriceps and hamstrings muscles were recorded. RESULTS: The mean knee extensor torque produced in the BL condition (168 +/- 52 Nm) was 17% less than the sum of the two UL conditions (Sigma=202 +/- 56 Nm). During BL conditions, quadriceps EMG activity was less in both legs (left, 8.2 +/- 7.4% less and right, 13.9 +/- 9.1% less, respectively). There were no significant differences between BL and UL efforts for either left or right hamstrings activity. Eighteen subjects, who when asked to perform a maximal knee extension simultaneously activated their contralateral hamstrings, had significantly higher bilateral deficits (21%) compared to those who exhibited little or no contralateral hamstrings EMG activity (14%). CONCLUSIONS: The main findings of the study were that a bilateral strength deficit occurred when simultaneously maximally activating the homologous knee extensor muscles. This deficit was in all likelihood due to a less than maximal efferent drive to the quadriceps muscles. Hamstrings EMG activity was not greater during the BL knee extensions, which supports the notion that antagonistic muscle activity was not primarily responsible for the observed bilateral deficit.