Longitudinal muscle strength changes in older adults: influence of muscle mass, physical activity, and health.
Level 3 - non-randomized controlled study
Longitudinal cohort follow-up study over ~9.7 years.
PubMed 11320101 · doi:10.1093/gerona/56.5.b209
What was done
Researchers evaluated longitudinal changes in isokinetic strength (knee and elbow extensors and flexors), muscle mass, physical activity, and health markers in 120 adults (68 women, 52 men) initially aged 46 to 78 years who were reexamined after an average follow-up of 9.7 ± 1.1 years.
What was found
Isokinetic strength declined by an average of 14% per decade for knee extensors and 16% per decade for knee flexors across both sexes. Women had slower decline rates in elbow extensors and flexors (2% per decade) than men (12% per decade). Older individuals showed greater rates of decline. In men, longitudinal rates of leg strength decline were approximately 60% greater than cross-sectional estimates from the same cohort. Leg strength changes were directly related to muscle mass changes in both sexes and inversely related to medication use changes in men. Physical activity declined but did not directly correlate with strength loss. Strength declined even among participants who maintained or gained muscle mass.
Why it matters
This study shows that cross-sectional studies can substantially underestimate the rate of age-related strength decline in men, and demonstrates that preserving muscle mass alone does not prevent the loss of muscle strength with aging.
Limits
The sample size is relatively small (120 participants) and potential survivor or retention bias may affect the cohort over a 10-year follow-up. Underlying cellular, neural, or metabolic contributors to strength loss were not directly measured.
Cited by
- context Human muscle performance peaks around the third decade of life, after which people lose approximately 10% of muscle strength and mass every 10 years, with loss accelerating beyond 10% per decade in their 60s.