The majority of the strength training studies in older adults have incorporated fixed-form exercises using seated resistance training machines. In light of the modest improvements in physical function shown in these studies, functional or task-specific exercises, involving movement patterns that mimic daily activities, have been studied. Free-form exercises, using free-weights or cable, is another form of functional strength training. Currently, no intervention studies exist comparing free-form exercises, using cable machines, and fixed-form exercises, using seated machines in older adults.
A total of 29 independently-living older adults, 65years or older, were randomized into two groups, seated machine (SM, n=10) and standing cable (SC, n=12). After 12weeks of training twice per week, groups were compared. The primary outcome was the Physical Performance Battery (PPB), a measure of physical function. Secondary outcomes were lower and upper body strength and power, activities of daily living evaluated by multiple tests including: Physical Performance Test (PPT), pan carry and gallon jug transfers, ratings of perceived exertion (RPE), and self-reported function using Patient Reported Outcomes Measurement Information System (PROMIS). Outcome assessors were blinded to participants' intervention assignments.
The PPB (SC=0.23 points; SM=0.15 points) showed clinical and significant improvements, but there was no significant difference between the groups (g=0.2, 95% CI (- 0.6, 1.0). For secondary outcomes, chair stand (g=0.7, 95% CI (0.2, 1.6), p=0.03) and pan carry (g=0.8, 95% CI (0.07, 1.07), p=0.04) favored SC, while chest press 1RM (g=0.2, 95% CI (0.06, 1.1), p=0.02) favored SM. There were no statistically significant group differences between PPB, gallon jug transfer, leg press 1RM, power, RPE or self-reported function.
Standing cable training was not superior to seated machine training in improving physical performance in older adults. However, both training interventions were effective in improving function. The findings also suggest that exercise specificity should be considered when prescribing resistance exercises to improve physical function in older adults.