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

Background: 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.

Methods: 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).

Results: 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.

Conclusions: 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.