Longitudinal Muscle Strength Changes in Older Adults: Influence of Muscle Mass, Physical Activity, and Health

Abstract

The longitudinal changes in isokinetic strength of knee and elbow extensors and flexors, muscle mass, physical activity, and health were examined in 120 subjects initially 46 to 78 years old. Sixty-eight women and 52 men were reexamined after 9.7 +/- 1.1 years. The rates of decline in isokinetic strength averaged 14% per decade for knee extensors and 16% per decade for knee flexors in men and women. Women demonstrated slower rates of decline in elbow extensors and flexors (2% per decade) than men (12% per decade). Older subjects demonstrated a greater rate of decline in strength. In men, longitudinal rates of decline of leg muscle strength were approximately 60% greater than estimates from a cross-sectional analysis in the same population. The change in leg strength was directly related to the change in muscle mass in both men and women, and it was inversely related to the change in medication use in men. Physical activity declined yet was not directly associated with strength changes. Although muscle mass changes influenced the magnitude of the strength changes over time, strength declines in spite of muscle mass maintenance or even gain emphasize the need to explore the contribution of other cellular, neural, or metabolic mediators of strength changes.

Age-related decline in muscle mass and muscle function in Flemish Caucasians: a 10-year follow-up

“…They found percent changes per year of −2.56 ± 1.1 % in isokinetic strength of the knee extensors at 60°/s and −4.2 ± 1.2 % at 240°/s, but this study only considered 12 subjects (five men) (Frontera et al 2008). Hughes et al (2001) found declines in isokinetic speed at 60°/s of −1.18 ± 1.55 % in women and −1.45 ± 1.56 % in men, which is more in line with our results (Hughes et al 2001). Their reported percent change per year is still larger, but it is probably explained by the older age range of their sample (46 to 78 years), whereas we considered subjects between 19 and 73 years old (baseline) (Hughes et al 2001).…”

“…Hughes et al (2001) found declines in isokinetic speed at 60°/s of −1.18 ± 1.55 % in women and −1.45 ± 1.56 % in men, which is more in line with our results (Hughes et al 2001). Their reported percent change per year is still larger, but it is probably explained by the older age range of their sample (46 to 78 years), whereas we considered subjects between 19 and 73 years old (baseline) (Hughes et al 2001). However, if we only considered subjects above 46 years of age, Δ percentage/year was −0.96 ± 2.16 % in women and −0.77 ± 2.28 % in men.…”

“…It should also be noted that study populations often consisted of a homogenous group, mostly older adults, and although in most cases this is a strength, it allows for a limited interpretation of lifelong changes in these parameters (Goodpaster et al 2006;Frontera et al 2008;Delmonico et al 2009;Dey et al 2009;Reid et al 2014). Nevertheless, results between studies are similar, pointing out losses in muscle mass of up to 12.9 and 5.3 % after a 9.7-year followup period in men and women, respectively, aged 45-75 years (Hughes et al 2001). In addition, isometric strength decreased with~0.87 % per year in men aged between 45 and 49 years, whereas declines in isokinetic strength were up to 2.56 % per year at 60°/s and 4.20 % per year at 240°/s in 62-81-year-old men and women (Frontera et al 2008;Kennis et al 2014).…”

Matched‐cohort study of body composition, physical function, and quality of life in men with idiopathic vertebral fracture

“…However, the correlations between muscle mass and strength, physical function, and quality of life did not obtain significance in patients with vertebral fracture. Possibly poor muscle quality, poor neural recruitment, or reduced effort may influence poor physical functioning in these patients (40,41). Consistent with the latter explanation was the finding that self-reported pain, one of the domains of the SF-36 quality of life questionnaire, was correlated with both muscle strength and physical functioning in patients with vertebral fracture.…”

Changes in physical performance among high-functioning older adults: a 6-year follow-up study

“…Previous longitudinal studies have reported selection of the study population to healthier and more mobile subjects (Aniansson et al 1983;Rantanen et al 1997;Rantanen and Heikkinen 1998;Hughes et al 2001;Paterson et al 2004). The selection bias will lead to underestimations of the performance and fitness changes with aging (Rantanen et al 1997), and will cause the population estimates of physical performance, if used as norm reference values, to be too high.…”