ABSTRACT
OBJECTIVES: This investigation examined the effect of 6 months of high- or low-intensity resistance exercise on muscular strength and endurance and stair climbing ability in adults aged 60 to 83. DESIGN: A randomized controlled trial. SETTING: University of Florida Center for Exercise Science. PARTICIPANTS: Sixty-two men and women completed the study protocol. Subjects were matched for strength and randomly assigned to a control (n = 16), low-intensity (LEX, n = 24), or high-intensity (HEX, n = 22) group. INTERVENTION: Six months of progressive, whole-body resistance training. Subjects trained at 50% of their one-repetition maximum (1RM) for 13 repetitions (LEX) or 80% of 1RM for eight repetitions (HEX) three times per week for 24 weeks using resistance machines. One set each of 12 exercises was performed. MEASUREMENTS: One-repetition maximum was measured for eight different exercises. Muscular endurance was measured using leg press and chest press machines. Low back strength was measured using a lumbar extension machine. Stair climbing ability was assessed as the time to ascend one flight of stairs. RESULTS: 1RM significantly increased for all exercises tested for the HEX and LEX groups (P < or =.050). The increases in total strength (sum of all eight 1RMs) were 17.2% and 17.8% for the LEX and HEX groups, respectively. Muscular endurance improved by 79.2% and 105.0% for the leg press, and 75.5% and 68.0% for the chest press for the LEX and HEX groups, respectively. The time to ascend one flight of stairs significantly decreased for both the LEX and HEX groups (P < or =.050). Lumbar extension strength increased by 62.6% and 39.5% for the LEX and HEX groups, respectively. CONCLUSIONS: These data indicate that significant and similar improvements in strength, endurance, and stair climbing time can be obtained in older adults as a consequence of high- or low-intensity resistance exercise training. These findings may have an effect on how resistance exercise is prescribed to older adults.
