狗的无氧阈与骨骼肌某些特征在锻炼、脱锻炼动态变化中的关系

本实验在体力锻炼与脱锻炼过程中观察了五条成年雄性杂种狗的无氧阈(AT)、骨骼肌毛细血管密度(cap/mm~2)、毛细血管数与肌纤维数之比(C:F)、肌纤维组成——慢肌纤维百分比(％ST)以及毛细血管弥散距离(弥散距离)的变化。结果表明:锻炼前AT与cap/mm~2、C:F,％ST及弥散距离均分别有显著相关。锻炼后第五周,AT、cap/mm~2、C:F和％ST分别增加了40.9％、12.2％、22.9％和2.4％,弥散距离降低6.3％,其中只有AT的增加有显著意义,锻炼十周后,AT增加68.2％(P<0.001)、cap/mm~2增加37.8％(P<0.05)、C:F增加78.1％(P<0.001),弥散距离降低17.0％(P<0.01)而％ST无显著变化。停止锻炼后第五周,AT等各指标都有降低的趋势,但无显著意义,停止锻炼后第12周,AT、cap/mm~2,C:F,％ST分别降低了18.9％、10.9％、10.5％、2.9％,弥散距离增加5.1％,其中除AT的降低有显著意义外,其余指标的变化均无显著意义。与锻炼前相比,这些指标的变化。除％ST外,仍有显著变化。在锻炼与脱锻炼的过程中,AT与cap/mm~2、C:F、弥散距离在各期或整个过程中均呈显著相关,但与％ST相关不显著。实验结果提示,骨骼肌的毛细血管供应状况是决定无氧阈的重要因素之一。

THE RELATIONSHIP BETWEEN ANAERORBIC THRESHOLD AND SOME FEATURES OF SKELETAL MUSCLE IN TRAINING AND DETRAINING IN DOGS

Five male adult mongrel dogs were subjected to train for 10 wks and detrain for 12 wks. During the course of training and detraining , the anaerobic threshold (AT),the supply of capillary to skeletal muscle (cap /mm2), muscle fiber composition(%ST), the ratio of capillary to mascie fiber (C:F ratio) and diffuse distance were determinted. Before testning, the AT was correlated withcap/mm2, C:F ratio, %ST and diffuse distance significently. After training, the AT, cap/mm, C:F ratio increased by 68.2%, 37.8%, 78.1%, respectively. Diffuse distance decreased by 17.0%. The differences were statistically significant. After detraining, the AT, cap/mm2, C:F ratio decreased by 18.9% , 10.9%, and 10.5%, respectively. Diffuse distance increased by 5.1%. Beside the difference in AT, the differences in other indices were not significant. The %ST was unchanged during the course of training and detraining. The results showed that the AT was changed with training and detraining. Meanwhile, parellel changes in the density of capillary (cap/mm) and C:F ratio and diffuse distance also occurred.The changes of cap/mm2, C : F ratio and diffuse distance were highly correlated with the changes of AT both in training and in detraining. It is suggested that the AT of animals is, partly, dependent upon the capillary supply of the muscle fiber.