Detraining and retraining in older adults following long-term muscle power or muscle strength specific training

Background. Training cessation among older adults is associated with the loss of functional ability. However, exercise programs undertaken prior to activity cessation may offer functional protection. In the present study, the residual effects of muscle power or muscle strength training were investigated following extended detraining and subsequent retraining. Methods. Thirty-eight healthy independent older adults (65-84 years) entered a 24-week detraining period subsequent to 24 weeks of training. Following detraining, participants recommenced training using either the high-velocity muscle power (HV) or muscle strength (ST) protocol, as undertaken during the initial training period, twice weekly for 12 weeks. Isometric and dynamic muscle strength, muscle power, movement velocity, muscle endurance, electromyographic activity, and the results of a battery of functional performance tasks were assessed. Results. Muscle function and functional performance increased following initial training, however, no group differences were observed. Detraining resulted in similar declines in muscle power and muscle strength for both groups (p < .05) (power, HV 17.8 [+ or -] 1.8%, ST 15.5 [+ or -] 2.2%; and strength, HV 17.1 [+ or -] 2.2%, ST 16.5 [+ or -] 1.8%), with comparable accrual following retraining. No significant changes in functional ability were observed following detraining (average change; HV 3.1 [+ or -] 3.5% and ST 2.1 [+ or -] 3.5%) or retraining. No group differences emerged in this study. Conclusion. Cessation of training resulted in only a modest loss of muscle power and strength that was recouped following 12 weeks of retraining. Importantly, training-induced gains in functional performance were preserved during detraining. The residual effects of power or strength training appear comparable, and both may be suitable exercise modes prior to a period of activity cessation to promote physical independence. Key Words: Resistance training--Functional performance--Muscle function--Detraining--Retraining.