Plasticity of skeletal muscle mitochondria: structure and function.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing physiological adaptations and molecular mechanisms without systematic search methodology.
PubMed 12544642 · doi:10.1249/01.MSS.0000043292.99104.12
What was done
This narrative review summarizes physiological and molecular literature on skeletal muscle mitochondrial adaptations to varied stimuli, including endurance exercise, strength training, high-fat diet, disuse (bed rest and microgravity), and severe hypoxia, with a focus on transcriptional signaling mechanisms.
What was found
Endurance training interventions lasting a few weeks in previously untrained individuals increase mitochondrial volume by up to 50% and double intramyocellular lipid content. A high-fat diet increases intramyocellular lipids without expanding mitochondrial volume. Strength training alters myofibrillar volume while leaving mitochondrial volume relatively unchanged. Bed rest and microgravity decrease both myofibrillar and mitochondrial volume. Severe hypoxia reduces muscle mass and oxidative capacity while altering transcriptional profiles.
Why it matters
It outlines how metabolic and mechanical demands modulate mitochondrial density and substrate utilization through specific nuclear and mitochondrial transcriptional pathways.
Limits
The abstract describes a narrative review without systematic search criteria, meta-analytic pooling, risk of bias assessments, or precise statistical estimates and sample sizes for the underlying primary studies.
Cited by
- context Training for a marathon can double the quantity of mitochondria in skeletal muscle.