Remaud Anthony, Cornu Christophe, Guével Arnaud
Université de Nantes, 25 bis boulevard Guy Mollet, BP 72206, 44322 Nantes Cedex 3, France.
J Athl Train. 2005 Oct-Dec;40(4):281-7.
Although isotonic and isokinetic exercises are commonly used in sports medicine and rehabilitation, studies comparing their effects on the neuromuscular system have provided conflicting results.
To compare responses of the neuromuscular system to isotonic and isokinetic contractions by controlling the total external amount of work performed and the mean angular movement velocity.
A familiarization session was followed by isotonic and isokinetic sessions of tests performed on an isokinetic dynamometer. Each subject participated in 3 sessions.
A sport sciences research laboratory.
Nine healthy adult males with no history of knee injury.
INTERVENTION(S): The isotonic session consisted of 3 sets of 8 knee extensions at 80% of each subject's maximal voluntary isotonic contraction. The isokinetic session involved 3 sets of n knee extensions at a preset velocity equivalent to the mean velocity measured during the corresponding isotonic sets; n represented the number of repetitions subjects had to achieve to equalize the total external amount of work performed during the corresponding isotonic sets.
MAIN OUTCOME MEASURE(S): We recorded mechanical parameters, n, and surface electromyographic signals from the vastus medialis, rectus femoris, and vastus lateralis muscles. Then root mean square, mean power frequency, and neuromuscular efficiency values were calculated for each repetition.
As expected, the total external amount of work and mean angular velocity were similar between the isotonic and isokinetic sessions. The number of repetitions performed was equivalent in both sessions. In addition, although no "shift" of mean power frequency occurred, mean neuromuscular efficiency decreased linearly with repetitions for both modes in no differentiated way.
Standardization of isotonic and isokinetic contractions based on total external amount of work and movement velocity is possible. This method can be applied by future investigators aiming to compare chronic effects of these 2 contraction modes on the neuromuscular system.
尽管等张运动和等速运动在运动医学和康复中普遍使用，但比较它们对神经肌肉系统影响的研究结果却相互矛盾。
通过控制所做的总外部功量和平均角运动速度，比较神经肌肉系统对等张收缩和等速收缩的反应。
在等速测力计上进行测试，先进行一次适应性训练，随后进行等张和等速训练。每位受试者参加3次训练。
一个运动科学研究实验室。
9名无膝关节损伤史的健康成年男性。
等张训练包括以每位受试者最大自主等张收缩的80%进行3组每组8次的膝关节伸展。等速训练包括以与相应等张训练组中测得的平均速度相等的预设速度进行3组n次膝关节伸展；n代表受试者为使相应等张训练组中所做的总外部功量相等而必须完成的重复次数。
我们记录了机械参数、n以及股内侧肌、股直肌和股外侧肌的表面肌电信号。然后计算每次重复的均方根、平均功率频率和神经肌肉效率值。
正如预期的那样，等张训练和等速训练之间的总外部功量和平均角速度相似。两组的重复次数相当。此外，尽管平均功率频率没有发生“偏移”，但两种模式下的平均神经肌肉效率均随重复次数呈线性下降，且无差异。
基于总外部功量和运动速度对等张收缩和等速收缩进行标准化是可行的。这种方法可供未来旨在比较这两种收缩模式对神经肌肉系统慢性影响的研究人员使用。
