Impact Of Training Modality On Strength And Physical Function Improvement In Older Adults

Abstract

The importance of maintaining strength in older adults is well documented and several training modes have been recommended; however, the effectiveness of each has not been completely characterized. Specifically, the interrelationships among mode, strength adaptations, and lower extremity physical function (LEPF) warrant further investigation. PURPOSE: The primary aims of this study were to 1) examine the effectiveness of cardiovascular (CV) to balance, flexibility, and functional strength (BAL) training on strength and LEPF and 2) explore the measure of muscle function most highly related to LEPF. METHODS: Forty-eight community-dwelling older adults (mean age 69.0 ±5.4 yrs, 31 female) were randomly assigned to 10-months of CV or BAL training. Muscle function, specifically knee extension and flexion at 120 deg/sec, was measured using an isokinetic dynamometer. LEPF was measured using a battery of tasks including stair ascent and descent, timed up-and-go, walk, and obstacle walk. Lower extremity mineral free lean mass (MFLM) was assessed using DXA. The CV group exercised using a variety of cardiovascular modes including treadmills, cycles, ellipticals, and a stair climber. The BAL group participated in a group exercise class that incorporated a wide variety of exercises for flexibility, balance, and functional strength, all completed at a low aerobic intensity level. RESULTS: Participants significantly improved peak torque and average power in combined leg extension and flexion (36.1% and 86.4%, respectively, p<0.05), with no group effect (p=0.34 and 0.72, respectively). Both groups also significantly improved performance on all LEPF tasks (3.5 to 7.7%, p<0.05) except timed up-and-go which declined (−5.8%, p<0.05), with a strong trend for CV improving more than BAL for walk (p=0.052), stair ascent (p=0.052), and timed up-and-go (p=0.063). Post intervention, LEPF performance was most highly correlated to average extension/flexion power normalized by leg MFLM (r = 0.48 to 0.68, p < 0.05). CONCLUSIONS: Previously sedentary older adults may achieve improvements in strength and LEPF with either CV or BAL training and these improvements are most closely related to average leg extension/flexion power normalized by leg MFLM.