Reisman Simone, Walsh Lee D, Proske Uwe
Department of Physiology, Monash University, Melbourne, Victoria, Australia.
Med Sci Sports Exerc. 2005 Jun;37(6):929-36.
A commonly used method for warm-up before exercise is to stretch muscles. How this benefits performance remains uncertain. After a period of eccentric exercise, there is muscle damage accompanied by an increase in passive tension, perceived as a sensation of increased stiffness in the exercised muscles. We have tested the idea that warm-up stretches might reduce levels of passive tension to reduce sensations of stiffness and soreness after eccentric exercise.
Subjects eccentrically exercised elbow flexors of one arm on an isokinetic dynamometer. The other arm acted as a control. After the exercise, measurements were made of resting elbow angle, as an indication of passive tension levels, before and after one or five large, passive arm extensions. Additional measurements made at 24 h included soreness levels in response to muscle stretch or vibration.
After the exercise, the relaxed elbow adopted a more flexed posture than normal, an effect that slowly subsided over the next 4 d. Five rapid arm extensions returned arm posture back to near control levels. The flexed posture then gradually re-developed over the next hour. At 24 h postexercise, extending the arm produced some soreness as did muscle vibration. The pain from arm extension and vibration was reduced after a series of arm extensions.
The flexed posture at the elbow is due to an increase in passive tension in elbow flexors as a result of muscle damage from the eccentric exercise. Stretch reduces passive tension. Benefits from the lower tension are reduced sensations of stiffness and soreness. This represents a new proposal for the mechanism for passive stretches as a warm-up strategy.
运动前常用的热身方法是拉伸肌肉。但其如何提高运动表现仍不明确。在进行一段时间的离心运动后，会出现肌肉损伤并伴有被动张力增加，表现为运动肌肉的僵硬感增强。我们测试了这样一种观点，即热身拉伸可能会降低被动张力水平，以减轻离心运动后肌肉的僵硬和酸痛感。
受试者在等速测力计上对一侧手臂的肘屈肌进行离心运动。另一只手臂作为对照。运动后，在进行一次或五次大幅度被动手臂伸展前后，测量静息时的肘部角度，以此作为被动张力水平的指标。在24小时时进行的额外测量包括对肌肉拉伸或振动的酸痛程度。
运动后，放松状态下的肘部比正常情况下更弯曲，这种效果在接下来的4天内逐渐消退。五次快速的手臂伸展使手臂姿势恢复到接近对照水平。然后在接下来的一小时内，弯曲姿势又逐渐恢复。运动后24小时，伸展手臂会引起一些酸痛，肌肉振动也会如此。经过一系列手臂伸展后，手臂伸展和振动引起的疼痛减轻。
肘部的弯曲姿势是由于离心运动导致肌肉损伤，使肘屈肌的被动张力增加所致。拉伸可降低被动张力。较低的张力带来的好处是僵硬和酸痛感减轻。这为被动拉伸作为热身策略的机制提出了一个新的观点。
