The loss of skeletal muscle strength, mass, and quality in older adults: the health, aging and body composition study.
Level 3 - non-randomized controlled study
Prospective longitudinal cohort study
PubMed 17077199 · doi:10.1093/gerona/61.10.1059
What was done
In a 3-year longitudinal study of 1,880 older adults from the Health, Aging and Body Composition (Health ABC) Study, researchers measured changes in muscle strength and body composition. Knee extensor strength was evaluated using isokinetic dynamometry, and whole-body and appendicular lean and fat mass were measured with dual-energy x-ray absorptiometry (DXA) and computed tomography (CT).
What was found
Both men and women experienced strength loss over 3 years, with men losing almost twice as much strength as women, and Black participants losing about 28% more strength than white participants. Annualized rates of leg strength decline (3.4% in white men, 4.1% in Black men, 2.6% in white women, 3.0% in Black women) were roughly three times faster than the loss of leg lean mass (~1% per year). Independent predictors of strength decline included lean mass loss, older age, higher baseline strength, and lower baseline leg lean mass. Gaining lean mass did not preserve or improve strength in men (regression coefficient: -0.48 ± 4.61, p = 0.92) or women (regression coefficient: -1.68 ± 3.57, p = 0.64).
Why it matters
Muscle strength declines much more rapidly than muscle mass in aging, indicating that reductions in muscle quality rather than quantity alone drive weakness. Strategies focused solely on preserving or increasing muscle mass may not be sufficient to maintain physical strength in older adults.
Limits
The abstract does not specify the exact age distribution, health status, or physical activity levels of participants. Follow-up was limited to 3 years, and strength assessments focused specifically on knee extensors rather than whole-body functional capacity.
Cited by
- supports Sedentary adults lose muscle mass at an accelerated rate of approximately 1% per year after age 40, and lose muscle strength at 1% to 3% per year.