Abstract
During submaximal exercise, there is a heterogeneous recruitment of skeletal muscle fibers, with an ensuing heterogeneous depletion of muscle glycogen both within and between fiber types. Here, we show that the mean (95% CI) mitochondrial volume as a percentage of fiber volume of non-glycogen-depleted fibers was 2 (−10:6), 5 (−21:11), and 12 (−21:−2)% lower than all the sampled fibers after continuing exercise for 1, 2 h, and until task failure, respectively. Therefore, a glycogen-dependent fatigue of individual fibers during submaximal exercise may reduce the muscular oxidative power. These findings suggest a relationship between glycogen and mitochondrial content in individual muscle fibers, which is important for understanding fatigue during prolonged exercise.
Original language | English |
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Article number | e14571 |
Journal | Scandinavian Journal of Medicine & Science in Sports |
Volume | 34 |
Issue number | 2 |
Number of pages | 6 |
ISSN | 0905-7188 |
DOIs | |
Publication status | Published - Feb 2024 |
Bibliographical note
Publisher Copyright:© 2024 The Authors. Scandinavian Journal of Medicine & Science In Sports published by John Wiley & Sons Ltd.
Keywords
- exercise
- fatigue
- glycogen
- mitochondria
- muscle fiber
- transmission electron microscopy