Journal Article Endurance Training-based Tapering Fails to Improve Fatigue Resistance of Rat Skeletal Muscle
Endurance Training-based Tapering Fails to Improve Fatigue Resistance of Rat Skeletal Muscle

Hirofumi, MANO  ,  Daiki, WATANABE  ,  Yuya, ISHII  ,  Katsutoshi, HIRANO  ,  Satoshi, MATSUNAGA  ,  Masanobu, WADA  ,  Graduate School of Integrated Arts and Sciences, Hiroshima University  ,  Graduate School of Integrated Arts and Sciences, Hiroshima University  ,  Graduate School of Integrated Arts and Sciences, Hiroshima University  ,  Graduate School of Integrated Arts and Sciences, Hiroshima University  ,  Faculty of Education and Culture, University of Miyazaki  ,  Graduate School of Integrated Arts and Sciences, Hiroshima University

Description
The aim of this study was to examine the effects of endurance training and endurance-based tapering on fatigue resistance of rat skeletal muscles. The rats were divided into one of five different groups: an age-matched sedentary group: the first trained group which was subjected to a 10-wk endurance training: the second trained group which continued endurance training for additional 10 days after the 10-wk training: the third trained group which remained sedentary for 10 days after the 10-wk training: the fourth trained group which underwent a taper program (an unaltered-intensity, reduced-volume taper) for 10 days after the 10-wk training. Following each treatment, measures of force output and biochemical analyses were performed on gastrocnemius muscles. Fatigue resistance and the activity of citrate synthase were increased by the 10-wk training, but unaltered by three treatments after the 10-wk training (additional training, detraining or tapering). Training brought about the exchange of myosin heavy chain (MHC) isoforms in order of MHC IIb→MHCIId/x→MHCIIa whereas detraining caused the exchange from MHCIIa to MHCIId/x. Training resulted in reductions in the Ca^<2+> sequestering ability of sarcoplasmic reticulum (SR) and detraining returned the reduced ability to pre-training levels. The present results indicate that fatigue resistance of intact whole muscle is improved by training but not, at least, by the tapering protocol used in this study and suggest that enhancement of oxidative potential contributes to improved fatigue resistance, whereas muscle fiber transitions from type IID/X to IIA fibers or decreases in the SR Ca^<2+> sequestering ability do not.
Full-Text

https://projects.repo.nii.ac.jp/?action=repository_action_common_download&item_id=194699&item_no=1&attribute_id=21&file_no=1

Number of accesses :  

Other information