Mair S D, Seaber A V, Glisson R R, Garrett W E
Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA.
Am J Sports Med. 1996 Mar-Apr;24(2):137-43. doi: 10.1177/036354659602400203.
We investigated the role of fatigue in muscle strain injuries using the extensor digitorum longus muscles of 48 rabbits. The muscles of the rabbits were fatigued by 25% or 50% then stretched to failure and compared with the contralateral controls. Three rates of stretch were used. The force to muscle failure was reduced in the fatigued leg in all groups (range, 93% to 97.4% compared with the controls). The change in muscle length in the fatigue groups was not different from the controls. The amount of energy absorbed in the fatigued muscle was 69.7% to 92% that of the energy absorbed in the control muscle. The lowest energy absorption occurred in muscles that were more fatigued. In eight additional rabbits, fatigued extensor digitorum longus muscles were compared with submaximally stimulated muscles with the equivalent contractile properties, and no difference was seen. Muscles subjected to strains are frequently injured under high-intensity eccentric loading conditions. Under these conditions, muscles absorb energy and provide control and regulation of limb movement. Our data showed that muscles are injured at the same length, regardless of the effects of fatigue. However, fatigued muscles are able to absorb less energy before reaching the degree of stretch that causes injuries.
我们使用48只兔子的趾长伸肌研究了疲劳在肌肉拉伤中的作用。兔子的肌肉先进行25%或50%的疲劳处理，然后拉伸至断裂，并与对侧对照进行比较。采用了三种拉伸速率。所有组中，疲劳侧腿部肌肉至断裂的力量均降低（与对照组相比，范围为93%至97.4%）。疲劳组肌肉长度的变化与对照组无差异。疲劳肌肉吸收的能量为对照肌肉吸收能量的69.7%至92%。疲劳程度越高的肌肉，能量吸收最低。在另外8只兔子中，将疲劳的趾长伸肌与具有同等收缩特性的次最大刺激肌肉进行比较，未发现差异。承受应变的肌肉在高强度离心负荷条件下经常受伤。在这些条件下，肌肉吸收能量并对肢体运动进行控制和调节。我们的数据表明，无论疲劳影响如何，肌肉在相同长度时都会受伤。然而，疲劳肌肉在达到导致损伤的拉伸程度之前能够吸收的能量较少。
