Enhanced Protein Translation Underlies Improved Metabolic and Physical Adaptations to Different Exercise Training Modes in Young and Old Humans.
Level 3 - non-randomized controlled study
Controlled clinical trial comparing three training modalities across age groups without explicit mention of randomization in the abstract.
PubMed 28273480 · doi:10.1016/j.cmet.2017.02.009
What was done
Young and older human adults completed 12 weeks of high-intensity aerobic interval training (HIIT), resistance training (RT), or combined exercise training. Researchers measured changes in insulin sensitivity, lean mass, aerobic capacity, skeletal muscle mitochondrial respiration, DNA promoter methylation, gene transcription, and proteome abundance (including translational machinery and mitochondrial protein synthesis).
What was found
The abstract reports directional findings without specific numerical values, percentages, or effect sizes: - All training modalities (HIIT, RT, and combined) increased insulin sensitivity and lean mass. - Only HIIT and combined training improved aerobic capacity and skeletal muscle mitochondrial respiration. - HIIT produced a more robust increase in gene transcripts than other modalities, particularly in older adults, but transcript changes showed little overlap with corresponding individual protein abundance. - HIIT reversed many age-related differences in the proteome, specifically increasing mitochondrial protein synthesis and mitochondrial protein abundance. - Both RT and HIIT increased proteins involved in the translational machinery across both age groups. - Only small changes in DNA promoter region methylation were observed.
Why it matters
This work shows that physical exercise alters muscle function predominantly via translational rather than transcriptional or DNA methylation regulation. It identifies HIIT as an effective strategy for restoring mitochondrial protein abundance and respiratory function in aging skeletal muscle.
Limits
The abstract provides no sample sizes, baseline participant characteristics, or exact quantitative values (p-values, point estimates, or variance). Randomization is not stated in the abstract, and durability of adaptations beyond 12 weeks was not evaluated.
Cited by
- supports In a sprint training study comparing older women (average age 58) to 18-to-30-year-olds, the older cohort achieved a 69% improvement in mitochondrial efficiency compared to a 49% improvement in the younger cohort.