耐力训练可降低体外膈肌疲劳的发生率。

Endurance training reduces the rate of diaphragm fatigue in vitro.

作者信息

Vrabas I S, Dodd S L, Powers S K, Hughes M, Coombes J, Fletcher L, Demirel H, Reid M B

机构信息

Department of Exercise and Sport Sciences, University of Florida, Gainesville 32611, USA.

出版信息

Med Sci Sports Exerc. 1999 Nov;31(11):1605-12. doi: 10.1097/00005768-199911000-00017.

DOI:10.1097/00005768-199911000-00017

PMID:10589864

Abstract

PURPOSE

The present study examined the effects of endurance training on the contractile and biochemical properties of the rat costal diaphragm in vitro.

METHODS

Sixty-four rats were divided into two groups: exercise trained (T) and control (C). Training consisted of treadmill running 5 d x wk(-1), 60 min x d(-1) at approximately 70% of VO2max, over a 10-wk period.

RESULTS

Control diaphragm strips produced an average of 12% less force from minute 15 to 50 of a 60-min in vitro fatigue protocol, compared with the T diaphragm strips (P < 0.01). T diaphragms had 10.1% higher citrate synthase (CS) and 12.1% higher superoxide dismutase (SOD) activities compared with the C (P < 0.05). Despite a significant decrease (P < 0.05) in Type IIb myosin heavy chains (MHC) and an increase (P < 0.05) in Type I MHC in T diaphragms, maximal shortening velocity (Vmax) in the diaphragm was not different between T and C animals. No differences were observed in specific force or the relative proportions of myosin light chains between groups.

CONCLUSIONS

These findings suggest that endurance training reduces the rate of diaphragm fatigue in vitro but has no effect on Vmax or specific force.

摘要

目的

本研究检测了耐力训练对大鼠体外肋膈膜收缩和生化特性的影响。

方法

64只大鼠被分为两组：运动训练组（T）和对照组（C）。训练包括在10周的时间里，每周5天、每天60分钟在跑步机上跑步，速度约为最大摄氧量的70%。

结果

在60分钟的体外疲劳实验中，从第15分钟到第50分钟，与T组膈膜条相比，C组膈膜条产生的平均力量少12%（P < 0.01）。与C组相比，T组膈膜的柠檬酸合酶（CS）活性高10.1%，超氧化物歧化酶（SOD）活性高12.1%（P < 0.05）。尽管T组膈膜中IIb型肌球蛋白重链（MHC）显著减少（P < 0.05），I型MHC增加（P < 0.05），但T组和C组动物膈膜的最大缩短速度（Vmax）没有差异。两组之间在比力或肌球蛋白轻链的相对比例上没有观察到差异。