Long-Term Impact of Strength Training on Muscle Strength Characteristics in Older Adults

Objective: To evaluate the long-term preventive impact of strength training on muscle performance in older adults. Design: A 7-year follow-up on a 1-year randomized controlled trial comparing the effects of combined resistance training and aerobic training and whole-body vibration training on muscle performance. Setting: University training center. Participants: Men and women (N=83; control [CON] group, n=27; strength-training intervention [INT] group, n=56) between 60 and 80 years of age. Interventions: The INT group exercised 3 times weekly during 1 year, performing a combined resistance training and aerobic training program or a whole-body vibration training program. The former training program was designed according to American College of Sports Medicine guidelines. The whole-body vibration training program included unloaded static and dynamic leg exercises on a vibration platform. The CON group did not participate in any training program. Main Outcome Measures: Static strength (STAT), dynamic strength at 60 degrees/s (DYN60) and at 240 degrees/s (DYN240), speed of movement at 20% (S-20). Results: From baseline to postintervention, muscle performance did not change in the CON group, except for S-20 (+6.55%+/- 2.88%, P<.001). One year of strength training increased (P<.001) STAT (+11.46%+/- 1.86%), DYN60 (+6.96%+/- 1.65%), DYN240 (+9.25%+/- 1.68%), and S-20 (+7.73%+/- 2.19%) in the INT group. Between baseline and follow-up, muscle performance decreased (P<.001) in both groups. However, STAT and DYN60 showed a significantly lower loss in the ENT group (-8.65%+/- 2.35% and 7.10%+/- 2.38%, respectively) compared with the CON group (-16.47%+/- 2.69% and -15.08%+/- 2.27%, respectively). This positive impact might be due to the preservation of the training-induced gains, given the similar annual decline rates in both groups from postintervention to follow-up. Additionally, in trained participants, aging seems to impact velocity-dependent strength and power more compared with basic strength, as the total losses in DYN240 (CON, -15.93%+/- 2.64%; -11.39%+/- 1.95%) and S-20 (CON, -14.39%+/- 2.10%; INT, -13.16%+/- 1.72%) did not differ significantly between the groups. Conclusions: A 1-year strength-training intervention results in an improved muscle performance in older adults 7 years after their enrollment in the intervention. However, an extensive exercise program cannot attenuate the age-related decline once the intervention stops. (C) 2013 by the American Congress of Rehabilitation Medicine