Fredsted Anne, Clausen Torben, Overgaard Kristian
Department of Physiology, University of Aarhus, Aarhus, Denmark.
J Strength Cond Res. 2008 Jul;22(4):1136-46. doi: 10.1519/JSC.0b013e318173db9b.
Eccentric exercise often produces severe muscle damage, whereas concentric exercise of a similar load elicits a minor degree of muscle damage. The cellular events initiating muscle damage are thought to include an increase in cytosolic Ca. It was hypothesized that eccentric muscle activity in humans would lead to a larger degree of cell damage and increased intracellular Ca accumulation in skeletal muscle than concentric activity would. Furthermore, possible differences between men and women in muscle damage were investigated following step exercise. Thirty-three healthy subjects (18 men and 15 women) participated in a 30-minute step exercise protocol involving concentric contractions with 1 leg and eccentric contractions with the other leg. Muscle Ca content, maximal voluntary contraction (MVC), and muscle enzymes in the plasma were measured. In a subgroup of the subjects, T2 relaxation time was measured by magnetic resonance imaging. No significant changes were found in muscle Ca content in vastus lateralis biopsy specimens in women or in men. Following step exercise, MVC decreased in both legs of both genders. The women had a significantly larger strength decrease in the eccentric leg than the men had on postexercise day 2 (p < 0.01). Plasma creatine kinase increased following step exercise, with a sevenfold higher response in women than in men on day 3 (p < 0.001). The women, but not the men, had an increase in T2 relaxation time in the eccentrically working adductor magnus muscle, peaking on day 3 (75%) (p < 0.001). In conclusion, step exercise does not lead to Ca accumulation in the vastus lateralis but does induce muscle damage preferentially in the eccentrically working muscles, considerably more in women than in men. This indicates that gender-specific step training programs may be warranted to avoid excessive muscle damage.
离心运动通常会导致严重的肌肉损伤，而类似负荷的向心运动只会引起轻微程度的肌肉损伤。引发肌肉损伤的细胞事件被认为包括胞质钙的增加。据推测，与向心运动相比，人体的离心肌肉活动会导致更大程度的细胞损伤以及骨骼肌细胞内钙积累增加。此外，还研究了男女在阶梯运动后肌肉损伤方面可能存在的差异。33名健康受试者（18名男性和15名女性）参与了一项30分钟的阶梯运动方案，其中一条腿进行向心收缩，另一条腿进行离心收缩。测量了肌肉钙含量、最大自主收缩（MVC）以及血浆中的肌肉酶。在部分受试者亚组中，通过磁共振成像测量了T2弛豫时间。女性和男性股外侧肌活检标本中的肌肉钙含量均未发现显著变化。阶梯运动后，男女双腿的MVC均下降。在运动后第2天，女性离心收缩腿的力量下降幅度显著大于男性（p < 0.01）。阶梯运动后血浆肌酸激酶升高，在第3天女性的反应比男性高7倍（p < 0.001）。女性而非男性，在进行离心收缩的大收肌中T2弛豫时间增加，在第3天达到峰值（75%）（p < 0.001）。总之，阶梯运动不会导致股外侧肌钙积累，但确实会优先在进行离心收缩的肌肉中诱发肌肉损伤，女性比男性更为严重。这表明可能需要制定针对性别的阶梯训练方案以避免过度的肌肉损伤。
