Lower extremity muscle mass predicts functional performance in mobility-limited elders

Abstract

Objectives-This study examined the influence of lower extremity body composition and muscle strength on the severity of mobility-disability in community-dwelling older adults.Methods-Fifty-seven older males and females (age 74.2 ± 7 yrs; BMI 28.9 ± 6 kg/m 2 ) underwent an objective assessment of lower extremity functional performance, the Short Physical Performance Battery test (SPPB). Participants were subsequently classified as having moderate (SPPB score > 7: n = 38) or severe mobility impairments (SPPB score ≤7: n = 19). Body composition was assessed using dual-energy X-ray absorptiometry and provided measures of bone mineral density (BMD), total leg lean mass (TLM) and total body fat. Maximal hip extensor muscle strength was estimated using the bilateral leg press exercise. Multiple logistic regression analysis was utilized to identify the significant independent variables that predicted the level of mobility-disability.Results-TLM was a strong independent predictor of the level of functional impairment, after accounting for chronic medical conditions, BMD, body fat, body weight and habitual physical activity. In a separate predictive model, reduced muscle strength was also a significant predictor of severe functional impairment. The severity of mobility-disability was not influenced by gender (p = 0.71). A strong association was elicited between TLM and muscle strength (r = 0.78, p < 0.01).Conclusions-These data suggest that lower extremity muscle mass is an important determinant of physical performance among functionally-limited elders. Such findings may have important implications for the design of suitable strategies to maintain independence in older adults with compromised physical functioning. Additional studies are warranted to assess the efficacy of lifestyle, exercise or therapeutic interventions for increasing lean body mass in this population.

Training implications of maximal forces on a computer-controlled and motor-driven leg press by age group, sex, footplate direction, and speed

“…This reduction in sex-related effects when body weight is considered is consistent with the literature, where the percentage difference in force produced by men relative to women drops 23-52% if forces are normalized to body weight (Lindle et al, 1997;Metter et al, 1997;Jozsi et al, 1999). Considering the lack of sex-related decreases in functional mobility despite significant reductions in both strength and weight in women (Reid et al, 2008), strength relative to body weight may be the true metric of interest to assess functional mobility.…”

“…Women have generally been shown to be weaker and lighter than men (Lindle et al, 1997;Metter et al, 1997;Jozsi et al, 1999;Reid et al, 2008). Older women, however, were not found to differ from older men in mobility disability despite this being predicted by lower extremity muscle mass and strength (Reid et al, 2008).…”

Age‐dependent changes in physical performance and body composition in community‐dwelling Japanese older adults

“…Reduced skeletal muscle mass appears to increase physical disability,36 particularly mobility disability 37. On the other hand, an increase in fat mass may cause greater functional disability and lower physical performance in older adults 38.…”

Comparação da força e capacidade funcional entre idosos praticantes de musculação, hidroginástica e não praticantes de exercícios físicos

“…Por outro lado, no estudo de Reid et al 33 foi encontrada correlação significativa do nível de atividade física com a força no teste de pressão de pernas em idosos com dificuldade de mobilidade. De forma geral, apesar de os idosos apresentarem diminuição do desempenho para a realização de atividades motoras do cotidiano, ainda conseguem realizá-las de forma satisfatória, mesmo aqueles que não praticam exercícios físicos regularmente, mas conseguem se manter ativos nas atividades de vida diária.…”