Garrett W E, Safran M R, Seaber A V, Glisson R R, Ribbeck B M
Duke University Medical Center, Orthopaedic Research Laboratories, Durham, NC 27710.
Am J Sports Med. 1987 Sep-Oct;15(5):448-54. doi: 10.1177/036354658701500504.
We compared the biomechanical properties of passive and stimulated muscle rapidly lengthened to failure in an experimental animal model. The mechanical parameters compared were force to tear, change in length to tear, site of failure, and energy absorbed by the muscle-tendon unit before failure. Paired comparisons were made between 1) muscles stimulated at 64 Hz (tetanic stimulation) and passive (no stimulation) muscles, 2) muscles stimulated at 16 Hz (wave-summated stimulation) and passive muscles, and 3) muscles stimulated at 64 Hz and at 16 Hz. Both tetanically stimulated and wave-summation contracted muscles required a greater force to tear (at 64 Hz, 12.86 N more, P less than 0.0004; and at 16 Hz, 17.79 N more, P less than 0.003) than their nonstimulated controls, while there was no statistical difference in failure force between muscles stimulated at 16 Hz and 64 Hz. The energy absorbed was statistically greater for the stimulated muscles than for the passive muscles in Groups 1 and 2 (at 64 Hz, 100% more, P less than 0.0003; and 16 Hz, 88% more, P less than 0.0002). In Group 3, the tetanically contracted muscle-tendon units absorbed 18% more energy than the wave-summated stimulated muscles (P less than 0.01). All muscles tore at the distal musculotendinous junction, and there was no difference in the length increase at tear between muscles in each group. These findings may lead to enhanced understanding of the mechanism and physiology of muscle strain injuries.
我们在一个实验动物模型中比较了被动和受刺激肌肉快速拉长至衰竭时的生物力学特性。所比较的力学参数包括撕裂力、撕裂时的长度变化、衰竭部位以及肌肉 - 肌腱单元在衰竭前吸收的能量。进行了以下配对比较：1）以64赫兹刺激的肌肉（强直刺激）与被动（无刺激）肌肉；2）以16赫兹刺激的肌肉（波峰总和刺激）与被动肌肉；3）以64赫兹刺激的肌肉和以16赫兹刺激的肌肉。与未受刺激的对照肌肉相比，强直刺激和波峰总和收缩的肌肉都需要更大的撕裂力（64赫兹时多12.86牛，P小于0.0004；16赫兹时多17.79牛，P小于0.003），而在16赫兹和64赫兹刺激的肌肉之间，衰竭力没有统计学差异。在第1组和第2组中，受刺激肌肉吸收的能量在统计学上比被动肌肉更多（64赫兹时多100%，P小于0.0003；16赫兹时多88%，P小于0.0002）。在第3组中，强直收缩的肌肉 - 肌腱单元比波峰总和刺激的肌肉多吸收18%的能量（P小于0.01）。所有肌肉均在远端肌腱连接处撕裂，每组肌肉撕裂时的长度增加没有差异。这些发现可能有助于增强对肌肉拉伤损伤机制和生理学的理解。
