Related Experiment Video
Updated: Jun 15, 2026

Quantification of Subcellular Glycogen Distribution in Skeletal Muscle Fibers using Transmission Electron Microscopy
Published on: February 7, 2022
Creatine supplementation spares muscle glycogen during high intensity intermittent exercise in rats
Hamilton Roschel1, Bruno Gualano, Marcelo Marquezi
1School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil. lanchajr@usp.br.
Background:
The effects of creatine (CR) supplementation on glycogen content are still debatable. Thus, due to the current lack of clarity, we investigated the effects of CR supplementation on muscle glycogen content after high intensity intermittent exercise in rats.
Methods:
First, the animals were submitted to a high intensity intermittent maximal swimming exercise protocol to ensure that CR-supplementation was able to delay fatigue (experiment 1). Then, the CR-mediated glycogen sparing effect was examined using a high intensity intermittent sub-maximal exercise test (fixed number of bouts; six bouts of 30-second duration interspersed by two-minute rest interval) (experiment 2). For both experiments, male Wistar rats were given either CR supplementation or placebo (Pl) for 5 days.
Results:
As expected, CR-supplemented animals were able to exercise for a significant higher number of bouts than Pl. Experiment 2 revealed a higher gastrocnemius glycogen content for the CR vs. the Pl group (33.59%). Additionally, CR animals presented lower blood lactate concentrations throughout the intermittent exercise bouts compared to Pl. No difference was found between groups in soleus glycogen content.
Conclusion:
The major finding of this study is that CR supplementation was able to spare muscle glycogen during a high intensity intermittent exercise in rats.
Related Concept Videos
Muscle Recovery and Fatigue
Energy Supply for Muscle Contraction
Exercise and Muscle Performance
Endurance exercises
Endurance exercises involve running, swimming, or cycling, which require repetitive movements with low force output. When a person engages in endurance exercise, a few noticeable changes occur in their skeletal muscles. For instance, the number of capillaries...
Metabolic States of the Body: Fasting and Starvation
Metabolic States of the Body: The Postabsorptive State
Initially, glycogen stored in the liver is broken down to release glucose into the bloodstream, while glycogen in the muscles is broken down to supply glucose for energy directly within the muscle cells. As glycogen stores diminish,...
