Lean, fast and strong: Determinants of functional performance in the elderly.

Abstract

The current literature indicates that functional capacity is associated with physical performance and body composition measurements in older adults. However, it is not clear which tests can best explain the functional capacity in this population. This study aimed to investigate the physical performance and body composition determinants of functional capacity in older adults. Twenty-four older adults (66.4 ± 4.7y) undertook body composition (body fat and muscle), rate of torque development (0-50 and 0-200 ms); countermovement jump (height, power and impulse); leg-press and seated-leg-curl 5-repetition maximum; and functional-performance tests (Timed-up-and-go, stair ascent and stair descent). Timed-up-and-go correlated with countermovement jump (height, R² = 0.303; power, R² = 0.198; and impulse, R² = 0.224) and 5-repetition maximum (seated-leg-curl, R² = 0.172). Stair ascent correlated with body fat (R² = 0.213), rate of torque development (0-50 ms/body fat, R² = 0.301; 0-200 ms_, R² = 0.197; 0-200 ms/body fat, R² = 0.340), countermovement jump (height, R² = 0.325; power/body fat, R² = 0.413; impulse/body fat, R² = 0.422) and 5-repetiton maximum (leg-press/body fat, R² = 0.384; seated-leg-curl/body fat, R² = 0.341). Stair descent correlated with rate of torque development (0-50 ms/body fat, R² = 0.164; 0-200 ms, R² = 0.203; 0-200 ms/body fat, R² = 0.213), countermovement jump (height, R² = 0.458; power, R² = 0.212; power/body fat, R² = 0.358; impulse, R² = 0.218; impulse/body fat, R² = 0.369) and 5-repetition maximum (leg-press/body fat, R² = -0.227; seated-leg-curl/body fat, R² = 0.209; seated-leg-curl, R² = 0.181). Higher body fat is associated with weaker stair ascent performance. An increase in the correlation coefficient was observed for the countermovement jump, rate of torque development, and 5-repetition maximum tests when normalized by body fat compared to the absolute values. Countermovement jump height presented the highest correlation to timed-up-and-go and stair descent, while impulse/body fat for stair ascent.