Noonan T J, Best T M, Seaber A V, Garrett W E
Orthopaedic Research Laboratory, Duke University Medical Center, Durham, North Carolina 27710.
Am J Sports Med. 1994 Mar-Apr;22(2):257-61. doi: 10.1177/036354659402200217.
This study was designed to detect the first evidence of injury to muscle induced by passive stretching. Rabbit extensor digitorum longus and tibialis anterior skeletal muscles were subjected to passive stretching at set force levels of 20% or 30% of load to failure. Both tibialis anterior and extensor digitorum longus muscles that were stretched to 30% exhibited no difference in the three tensile parameters when compared with their contralateral control specimens. Maximum contractile force was decreased after stretching. Tibialis anterior and extensor digitorum muscles that were stretched to 20% of control failure force showed no decrement in the tensile parameters or maximum contractile force. Histology of the extensor digitorum longus muscles stretched to 30% of failure force showed small focal areas of muscle fiber rupture and hemorrhage near the distal myotendinous junction. Tibialis anterior and extensor digitorum longus muscle-tendon units stretched to 30% of failure force suffered functional injury as their contractile ability decreased after stretching. In contrast, muscle-tendon units stretched to 20% of failure force suffered no decrement in contractile ability; therefore, a threshold for passive muscle stretch injury has been found. Furthermore, changes in contractile properties and histologic assessment appear to be more sensitive predictors of injury than measurement of structural failure properties.
本研究旨在检测被动拉伸引起肌肉损伤的首个证据。对兔趾长伸肌和胫骨前骨骼肌施加相当于负荷至破坏时20%或30%的设定力水平进行被动拉伸。与对侧对照标本相比，拉伸至30%的胫骨前肌和趾长伸肌在三个拉伸参数上均无差异。拉伸后最大收缩力降低。拉伸至对照破坏力20%的胫骨前肌和趾长伸肌在拉伸参数或最大收缩力方面没有降低。拉伸至破坏力30%的趾长伸肌组织学检查显示，在远端肌腱结合处附近有小面积的肌纤维破裂和出血。拉伸至破坏力30%的胫骨前肌和趾长伸肌肌腱单位在拉伸后收缩能力下降，因此遭受了功能性损伤。相比之下，拉伸至破坏力20%的肌腱单位收缩能力没有下降；因此，已发现被动肌肉拉伸损伤的阈值。此外，收缩特性的变化和组织学评估似乎比结构破坏特性的测量更能敏感地预测损伤。
