Effect of resisted knee flexion on knee extension torque

We tested the principle of "reversal of antagonists" by measuring the effect of resisted knee flexion on subsequent peak knee extension torque at velocities of 60 degrees/sec and 120 degrees/sec using an isokinetic dynamometer. We determined peak knee extension torques from torque curves produced during knee extension that was performed reciprocally with either passive or maximum voluntary resisted knee flexion. We used a crossover design so that all 18 healthy adult subjects performed knee extension reciprocally with both passive and resisted knee flexion. Paired means t tests revealed no statistically significant difference between the peak knee extension torques produced under the two knee flexion conditions either at 60 degrees/sec or 120 degrees/sec. We, therefore, concluded that resisted knee flexion does not augment peak knee extension torque under our conditions of testing. The concept of reversal of antagonists was not supported. Antagonistic muscle functioning, therefore, may be irrelevant to agonist isokinetic testing and training in neurologically healthy persons.     

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.     

Validity of knee flexion and extension peak torque prediction models

The primary purpose of this study was to test the validity of predictive models relating isokinetic knee torque production to anthropometric and demographic variables. Subjects were 23 healthy female and 15 healthy male volunteers between the ages of 10 and 77 years. We measured subjects' peak knee flexion and extension torque production at two angular velocities. For each torque dependent variable, we calculated a Pearson product-moment correlation coefficient between the measured torque values and the values obtained with prediction equations. The difference between the squared value of the correlation coefficients and the regression multiple R2 values obtained for an original group of 134 subjects ranged between .05 and .10 for the torque dependent variables. The results indicate the validity of the regression models at the level specified by the multiple regression R2 values. Clinicians can use the prediction equations presented in this article to establish rehabilitation goals for patients and can estimate the error involved in applying each prediction equation.     

Decreased isometric knee flexion torque with hip extension in hemiparetic patients

I measured the 90-degree isometric knee flexion torque of 12 hemiparetic patients while they performed unilateral knee flexion in sitting and supine positions. The measurements were taken to clarify why hemiparetic patients have difficulty flexing their involved knees when their involved hip is extended. The patients generated more torque in the sitting position than in the supine position and more torque on their nonparetic side than on their paretic side. The ratio of supine-to-sitting knee flexion torque did not differ significantly between sides. This finding suggests that hemiparetic patients do not have relatively greater difficulty generating knee flexion torque on their involved side with the hip extended than with the hip flexed. Recommendations for assessment and treatment are made with this finding in mind.     

膝关节屈肌和伸肌等速向心性收缩峰力矩角度的研究

目的　了解影响峰力矩角度 (AOPT)的因素 ,确定向心性屈、伸膝峰力矩角度的正常值范围。方法　共 3 0 0名小于 65岁的正常成人 ,用Cybex3 3 0型等速仪器测试 60 (°) /s、180 (°) /s和 3 0 0 (°) /s屈、伸双膝的AOPT ,利用多因素方差分析和多元线性回归分析年龄、性别、速度、峰力矩和加速度对AOPT的影响 ,建立回归方程。结果　除女性屈膝组外 ,年龄对慢速AOPT无明显影响 ;女性屈、伸膝AOPT均较男性后移 ;随速度增快屈、伸膝AOPT均后移 ;60 (°) /s屈膝峰力矩与AOPT呈负相关 ,伸膝峰力矩与AOPT呈正相关 ;屈膝加速度时间与AOPT呈正相关 ,伸膝加速度与AOPT呈负相关。结论　慢速屈、伸膝AOPT主要受峰力矩的影响 ,本研究所确定的正常值范围可作为诊断或评价膝关节功能的一种辅助指标     

等速测试在腰椎间盘突出症患者康复评定中的应用

目的通过对腰椎间盘突出症(PLID)患者的下肢膝屈伸肌力的等速测试,定量评定患者的下肢膝屈伸肌力的变化,为制定PLID患者的康复训练计划提供依据。方法20例PLID患者,肌电图提示均有根性神经损害。采用Cybex330型等速运动测试装置,测试60°/s、180°/s、300°/s3种速度膝屈伸肌向心性等速运动峰力矩(PT)、平均功率(AP)、总做功量(TW)和力矩加速能(TAE),选用t检验比较双侧膝屈伸的PT、AP、TW和TAE比较有无差异。结果患侧3种速度膝屈伸的峰力矩、平均功率、总做功量和力矩加速能均低于健侧,差异均显著(P<0.05～0.01)。结论PLID患者患侧膝屈伸肌力均明显下降,当患者症状缓解,进行康复治疗训练腰背肌、腹肌的同时,还应加强患侧下肢膝屈伸肌力的训练。     

自然发育下男子膝关节屈伸肌群发展规律的等速肌力测试

目的:通过对9～20岁216名普通大、中、小学男生双侧膝关节进行等速测试,探讨青少年男子膝关节屈伸肌群随年龄增长的自然发育规律.方法:利用Kinitech等速测力系统对受试者双侧膝关节屈伸肌群进行等速测试,测试速度为60(°)/S,测试次数为屈伸6次.结果:青少年男子9～20岁膝关节屈伸肌的峰力矩随年龄增长均呈现出平稳的递增趋势,但伸肌各年龄段均大于屈肌,差异有显著性意义(P<0.05);屈伸肌最大功率随年龄的增长也争递增趋势,在9～15岁间的增长较快,15岁后最大功率增长逐步放缓,伸肌最大功率各年龄段均大于膝关节屈肌,但差异都没有表现出显著性(P>0.05);屈伸肌力比F/E值随年龄的增长整体呈递减趋势,9～13岁波动较大,13～20岁下降趋势较为显著.结论:9～20岁男子膝关节屈伸肌群力量、爆发力均随年龄的增长而自然增长,但表现出随年龄增长屈伸肌力比F/E值呈递减的趋势,形成自然成长下屈伸肌群发展不协调的现象.     

Test-retest reliability of isokinetic knee extension and flexion torque measurements in persons with spastic hemiparesis

The purpose of this study was to evaluate and compare the test-retest reliability of isokinetic torque measurements in the involved and uninvolved knee musculature of 20 subjects with spastic hemiparesis. An isokinetic dynamometer was used to measure maximal voluntary knee extension and flexion at 60 degrees and 120 degrees/s. Peak torque (PT) and average peak torque (APT) data were collected from five repetitions on two separate occasions. Average peak torque was defined as the mean of the PT values obtained during each of the five repetitions. Spasticity was measured in the involved knee musculature prior to isokinetic testing using the Ashworth Scale. Pearson Product-Moment Correlation Coefficients and intraclass correlation coefficients (ICCs) were high (greater than or equal to .90) for both knees for PT and APT at both angular velocities. No clinically meaningful differences were found between the Pearson correlation coefficients and the ICCs of the involved versus the uninvolved knee for any testing conditions. We concluded that isokinetic evaluation of torque, as measured by PT and APT in subjects with spastic hemiparesis, can yield reliable results in both extremities.     

Isometric and isokinetic knee extension and flexion torque in men and women aged 20-70

An investigation was made of the influence of age and sex on peak muscle torque in knee extension and flexion during maximal isokinetic and isometric contraction. The study was performed on both legs of 139 clinically healthy men and 141 clinically healthy women aged 20, 30, 40, 50, 60 or 70 years. Maximum knee extension and flexion muscle torque (Newtonmetre, Nm) was measured isokinetically at various angles of velocity (12, 90 and 150 degrees/s) and isometrically under standardized conditions (Cybex II). No significant differences were found between the right and the left leg in the whole material. Muscle torque was higher in men than in women in all age groups (p less than 0.001). Both isokinetic and isometric torque decreased with age in both sexes. Isokinetic torque decreased significantly (p less than 0.05) between 20 and 30 years of age in men and between 40 and 50 years of age in women (at all velocities studied; p less than 0.05). A significant decrease (p less than 0.05) was found between the ages of 60 and 70 years in both sexes. Maximum isometric torque showed a significant decrease (p less than 0.05) between 60 and 70 years in men and women. There were no significant differences in isokinetic or isometric torque between moderately active and inactive men or women. Significant correlations were found between muscle torque and body weight, height and body surface area.     

髌腱末端病运动员膝关节屈伸峰力矩和表面肌电图的特征（英文）

背景：髌腱末端病是腱止点部位的微细损伤,股四头肌群中的股内侧肌与股外侧肌之间的力量平衡发生变化,可直接导致髌骨产生异常运动从而对腱止点部位产生影响。目的：分析髌腱末端病发生机制和髌腱末端病对膝关节及其周围肌肉活动产生的影响。方法：选择10名患有髌骨肌腱病的男运动员及10名运动项目、身高和年龄匹配的正常男运动员,采用瑞士CON-TREX等速肌力测试与训练系统,分别进行膝关节力量和表面肌电图的测试,比较与分析膝关节屈肌力矩、伸肌力矩和股四头肌表面肌电图的变化。结果与结论：发现在等长运动时,末端病组的伸肌伸肌峰力矩明显小于对照组、峰值转矩比比值明显大于对照组;在等速运动时,末端病组的伸肌伸肌峰力矩明显小于对照组,并随着运动角速度增加而变化显著,而峰值转矩比比值均不同程高于对照组;末端病组的股内侧肌/股外侧肌的整合肌电图比值在等长运动和等速运动时,均明显低于对照组。提示髌腱末端病运动员膝关节屈肌与伸肌的力量差距较为突出,存在股内侧肌活动低下和股内侧肌与股外侧肌之间不平衡的现象。     

髌腱末端病运动员膝关节屈伸峰力矩和表面肌电图的特征(英文)

背景:髌腱末端病是腱止点部位的微细损伤,股四头肌群中的股内侧肌与股外侧肌之间的力量平衡发生变化,可直接导致髌骨产生异常运动从而对腱止点部位产生影响。目的:分析髌腱末端病发生机制和髌腱末端病对膝关节及其周围肌肉活动产生的影响。方法:选择10名患有髌骨肌腱病的男运动员及10名运动项目、身高和年龄匹配的正常男运动员,采用瑞士CON-TREX等速肌力测试与训练系统,分别进行膝关节力量和表面肌电图的测试,比较与分析膝关节屈肌力矩、伸肌力矩和股四头肌表面肌电图的变化。结果与结论:发现在等长运动时,末端病组的伸肌伸肌峰力矩明显小于对照组、峰值转矩比比值明显大于对照组;在等速运动时,末端病组的伸肌伸肌峰力矩明显小于对照组,并随着运动角速度增加而变化显著,而峰值转矩比比值均不同程高于对照组;末端病组的股内侧肌/股外侧肌的整合肌电图比值在等长运动和等速运动时,均明显低于对照组。提示髌腱末端病运动员膝关节屈肌与伸肌的力量差距较为突出,存在股内侧肌活动低下和股内侧肌与股外侧肌之间不平衡的现象。     

Test-retest reliability of isokinetic knee extension and flexion

OBJECTIVE: To assess reliability of isokinetic peak torque and work for knee flexion and extension. DESIGN: Single-group test-retest. SETTING: University laboratory. PARTICIPANTS: Eleven men and 7 women (mean age, 21 y). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Peak torque and work for concentric and eccentric knee extension and flexion were recorded at 60 degrees/s for 3 trials on 2 occasions. Intraclass correlation coefficient model 3,1 (ICC(3,1)), standard error (SE) of measurements, and smallest real differences were calculated for the maximum and for the mean peak torque and work of the 3 repetitions. RESULTS: Relative reliability was "very high" for peak torque and work (ICC range, >.90). The SE measurements ranged between 5% and 10% of the initial values for both peak torque and work. The smallest change that indicates a real improvement for a single subject (smallest real differences) ranged from 12% to 25% for peak torque and work variables and from 25% to 30% for the peak torque ratios. CONCLUSIONS: Isokinetic concentric and eccentric knee extensor and flexor strength variables are reliable when measured by the same examiner in asymptomatic subjects.     

腰椎间盘突出症伴神经异常屈、伸膝的肌力变化

目的为制定腰椎间盘突出症患者的康复训练计划提供依据.方法腰椎间盘突出症患者16例,根据肌电图检查分为L4和L5/S1神经损伤组.用Cybex330型等速运动测试装置,测试60°/s、180°/s、300°/s3种速度屈、伸膝向心性等速运动峰力矩,选用t检验比较双侧屈、伸膝的峰力矩和屈/伸膝比值有无差异.结果患侧3种速度屈、伸膝的峰力矩均低于健侧,屈膝时相差17.1%～22.5%,伸膝相差11.8%～17.3%,差异均显著(P＜0.05～0.001);L4组患侧3种速度的屈/伸比值均大于健侧,而L5/S1组患侧3种速度的屈/伸比值均小于健侧.结论腰椎间盘突出症患者患侧屈、伸膝肌力均明显下降,当患者症状缓解,进行康复治疗训练腰背肌的同时,不要忽略屈、伸膝肌力的训练.     

Relative decreases in knee extension torque with increased knee extension velocities in stroke patients with hemiparesis

I examined the isokinetic knee extension torque (KET) produced by the paretic and nonparetic lower limbs of 27 stroke patients, with hemiparesis, at knee extension velocities (KEVs) of 30 degrees, 60 degrees, 120 degrees, and 180 degrees/sec. The purpose of this study was to determine whether the relative decreases in KET at velocities greater than 30 degrees/sec were different on the two sides. To further investigate this relative decrease, the relationship between the torque at 30 degrees/sec and those at higher speeds also was examined on each side. Relative decreases in KET differed between speeds, but not between sides. Torques at speeds greater than 30 degrees/sec were correlated significantly with the torque at 30 degrees/sec. These findings suggest that patients with hemiparesis and minimal muscle spasticity may have difficulty moving forcefully at higher speeds because they are weak. Therapeutic interventions, therefore, might be most beneficial when they are directed toward helping patients with hemiparesis activate their weak muscles.     

偏瘫膝关节肌力的力学分析

目的强调肌力训练在偏瘫康复中的重要性,分析当前治疗误区,寻求最佳运动治疗对策。方法选择14例进行步态训练的偏瘫患者接受等速肌力标准化测试,在角速度分别为60、120、180rad/s下的双膝关节屈伸肌群的峰力矩(PT)与总作功(TW)。结果患侧伸膝肌群在3种角速度峰力矩分别为59.43、41.86、32.14N·m,总作功分别为61.14、46.93、36.57J,与健侧比较差异明显（P<0.01）。患侧屈膝肌群在3种角速度峰力矩分别为24.86、21.00、31.00N·m,总作功分别为26.07、18.86、13.43J。除120rad/s峰力矩双侧比较无显著意义外,其余P值均<0.01。结论传统康复治疗中神经促进技术等运动疗法训练后存在严重的肌力不足,应如何解决值得深思。     

Reliability of the passive knee flexion and extension tests in healthy subjects

ObjectiveInformation on the reliability of the passive knee extension (PKE) and passive knee flexion (PKF) tests is still incomplete. Moreover, standardization of the 2 test procedures could be enhanced. The present study investigates interrater and test-retest reliability of the modified versions of the PKE and PKF tests to establish whether the level of reliability is sufficiently high to justify their use in scientific studies and clinical practice.MethodsA total of 14 healthy subjects met the selection criteria. The 2 tests were carried out successively by each of the 3 clinicians/raters involved in the study, and each test was repeated 3 times. Two series of such measurements were performed. To evaluate interrater and test-retest reliability of the 2 tests, we calculated the intraclass correlation coefficients (ICCs), the standard errors of measurement, and the smallest detectable differences.ResultsThe PKE and PKF tests showed excellent and good reliability, respectively. Mean ICCs for the PKE were greater than those for the PKF. Mean ICCs for the interrater reliability (0.88-0.93) were higher than those for test-retest reliability (0.84-0.93). No mean ICCs lower than 0.84 were found (test-retest for PKF). The lowest ICCs of 0.73 and 0.75 were registered for the test-retest reliability of PKF in the case of rater 1.ConclusionThese results show excellent and good interrater and test-retest reliability of the PKE and PKF, respectively. The PKE test seems to be slightly more reliable. These findings may help clinicians when using these tests. For research purposes, investigators must critically evaluate whether the presented amount of error is acceptable for a specific setting.     

正常女青年膝关节等速屈伸肌力测试的研究

目的 通过调查正常女性静壮年膝关节的运动参数。为膝关节的运动功能康复提供依据。方法 应用ＢＩＯＤＥＸＭＵＬＴＩ－ＪＯＩＮＴＳＹＳＴＥＭＩＩＡＰ型等速装置对６２例正常女性青壮年膝关节进行等速屈伸力量测试左侧、膝伸肌大于膝屈肌、慢速测试大于快速测试;单次最大作功量（ＭＲＷ）测试结果有如下趋势;在同一测试速度下,膝屈伸肌测试值均为左侧大于右侧、膝伸肌大于膝屈肌,慢速测试大于快速测试;正常女性青壮年双侧膝     

正常男性青年膝关节等速屈伸力量测试研究

目的通过调查正常男性青年膝关节的运动参数,为膝关节的运动功能康复提供依据。方法应用ＢｉｏｄｅｘＭｕｌｔｉＪｏｉｎｔＳｙｓｔｅｍⅡＡＰ型等速装置对５４例正常男性青年膝关节进行等速屈伸力量测试研究。结果膝屈伸肌的峰力矩（ＰＴ）和单次最大做功量（ＭＲＷ）测试结果有如下趋势：在同一测试速度下,膝屈伸肌测试值均为右侧大于左侧、膝伸肌大于膝屈肌、慢速测试大于快速测试;总做功量（ＴＷ）测试结果也显示膝屈伸肌测试值均为右侧大于左侧、膝伸肌大于膝屈的变化趋势。正常男性青年双侧膝屈伸肌的差异范围为９．１１％～２０．０１％。１２０（°）／ｓ运动速度时的膝屈伸肌的运动效率最高,６０（°）／ｓ时的效率最低。结论本研究中的膝屈伸肌ＰＴ占体质量的比值（ＰＴ／ＢＭ,％）和膝屈伸肌肌力（峰力矩）比值（Ｆ／Ｅ,％）的测试结果与国内外的有关报道相近。不同的关节肌肉运动应有一个能最大限度发挥其效率的特定运动速度     

Reliability of knee extension and flexion measurements using the Con-Trex isokinetic dynamometer

The aim of this study was to evaluate the reliability of isokinetic and isometric assessments of the knee extensor and the flexor muscle function using the Con-Trex isokinetic dynamometer. Thirty healthy subjects (15 males, 15 females) were tested and retested 7 days later for maximal strength (isokinetic peak torque, work, power and angle of peak torque as well as isometric maximal voluntary contraction torque and rate of torque development) and fatigue (per cent loss and linear slope of torque and work across a series of 20 contractions). For both the knee extensor and the flexor muscle groups, all strength data - except angle of peak torque - demonstrated moderate-to-high reliability, with intraclass correlation coefficients (ICC) higher than 0.86. The highest reliability was observed for concentric peak torque of the knee extensor muscles (ICC = 0.99). Test-retest reliability of fatigue variables was moderate for the knee extensor (ICC range 0.84-0.89) and insufficient-to-moderate for the knee flexor muscles (ICC range 0.78-0.81). The more reliable index of muscle fatigue was the linear slope of the decline in work output. These findings establish the reliability of isokinetic and isometric measurements using the Con-Trex machine.