Optimal loads for power in older men and women using plate-loaded resistance machines

Age-related decrements in power affect quality of life in older adults; however, no studies have determined the optimal loads that maximize power outputs using the most commonly employed lifting equipment, plate-loaded machines.

Fifteen older men (69.2 ± 6.9 y) and 22 older women (68.9 ± 5.9 y) performed two sessions of strength and power testing. Individuals completed ten plate-loaded exercises to determine their maximum dynamic strengths (1RM) and peak power outputs (PP). Power was tested at 40, 50, 60, 70 and 80% 1RM using a linear position transducer. PP was expressed relative to the highest power produced (PP_REL).

Multi-joint exercises produced optimal load values at 50-60%1RM for leg press, 50%1RM for chest press, and 40-60%1RM for seated row, with no significant differences among loads for shoulder press. Single-joint exercise optimal loads were seen at 50-60% for hip adduction, 50-70%1RM for calf raise, 60-80%1RM for biceps curl, and 50-80%1RM for triceps extension, with no significant differences between loads for hip abduction or leg curl. No significant differences were found between sexes for any exercise.

Different optimal load ranges are required for individual plate-loaded exercises in older persons. Specifically, multi-joint exercises demonstrated a narrow optimal load range favoring the velocity end of the load-velocity curve, while single-joint exercises produced a wider optimal load range extending into the upper limits of the load end of the curve.