Almeida G L, Latash M L
Universidade Estadual de Campinas, Instituto de Reabilitação de Campinas, Sao Paulo, Brazil.
Med Sci Sports Exerc. 1995 Nov;27(11):1540-9.
We studied the effects of extensive practice of fast, unidirectional, single-joint elbow flexions against a small extending torque bias upon the kinematic and electromyographic (EMG) characteristics of the movements as well as upon the reconstructed hypothetical control patterns (equilibrium trajectories). The subjects were tested at different distances, both with and without the bias torque prior to and after the practice sessions. The basic finding was paradoxical: The subjects did not improve their performance at the practiced task (against the bias) and at other distances in the same condition; however, they showed an increase in movement speed and a decrease in movement time at all distances in unpracticed conditions (without the bias). Changes in the EMG patterns were similar in both conditions. We hypothesize that the principle of learning the dynamics of interaction with the experimental setup in combination with a very steep learning curve form the basis for the observed paradoxical effects of practice. The equilibrium-point hypothesis of movement control provides the least controversial description of these effects as compared to the force-control and EMG-control approaches.
我们研究了在存在小的伸展扭矩偏差的情况下，进行快速、单向、单关节肘部屈曲的大量练习，对运动的运动学和肌电图（EMG）特征以及对重建的假设控制模式（平衡轨迹）的影响。在练习阶段之前和之后，对受试者在不同距离下进行测试，测试时既有偏差扭矩，也无偏差扭矩。基本发现是自相矛盾的：受试者在练习任务（对抗偏差）以及相同条件下的其他距离处，其表现并未得到改善；然而，在未练习的条件下（无偏差），他们在所有距离处的运动速度均有所提高，运动时间有所缩短。两种条件下EMG模式的变化相似。我们推测，学习与实验装置相互作用的动力学原理，与非常陡峭的学习曲线相结合，构成了所观察到的练习的矛盾效应的基础。与力控制和EMG控制方法相比，运动控制的平衡点假设对这些效应的描述争议最小。
