TY - JOUR
T1 - Assessments of individual fiber glycogen and mitochondrial volume percentages reveal a graded reduction in muscle oxidative power during prolonged exhaustive exercise
AU - Nielsen, Joachim
AU - Jensen, Rasmus
AU - Ørtenblad, Niels
PY - 2024/1/28
Y1 - 2024/1/28
N2 - 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) mitochon-drial 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 be-tween glycogen and mitochondrial content in individual muscle fibers, which is important for understanding fatigue during prolonged exercise
AB - 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) mitochon-drial 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 be-tween glycogen and mitochondrial content in individual muscle fibers, which is important for understanding fatigue during prolonged exercise
U2 - 10.1111/sms.14571
DO - 10.1111/sms.14571
M3 - Journal article
SN - 0905-7188
VL - 34
JO - Scandinavian Journal of Medicine & Science in Sports
JF - Scandinavian Journal of Medicine & Science in Sports
IS - 2
M1 - e14571
ER -