Long-term resistance training in the elderly: effects on dynamic strength, exercise capacity, muscle, and bone.

We examined the effects of 42 weeks of progressive weight-lifting training on dynamic muscle strength, peak power output in cycle ergometry, symptom limited endurance during progressive treadmill walking and stair climbing, knee extensor cross-sectional areas, and bone mineral density and content in healthy males and females aged 60-80 years, currently enrolled in a 2-year resistance training program. Subjects were randomized into either exercise (EX) or control (CON) groups (60-70 years: 38 males and 36 females; 70-80 years: 25 males and 43 females). EX trained several muscle groups twice per week for 42 weeks at intensities ranging from 50-80% of the load that they could lift once only (1 RM); CON did usual daily activities. After the 10 months there was no change in 1 RM strength in CON, but significant gains (mean increases up to 65%) in EX (no independent age or gender effects); 30% and 47% of the increase in 1 RM had occurred by 6 and 12 weeks, respectively. In EX, the 7.1% increase in peak cycling power output was significantly greater than in CON (+1.1%). The 17.8% improvement in symptom limited treadmill walking endurance was also greater than in CON (+3.4%), but the difference between groups during stair climbing was not significant (EX + 57%, CON + 33%). The cross-sectional areas of the knee extensors increased significantly by 5.5% in EX but were unchanged in CON. There were no changes in bone mineral density or content in either group. We conclude that long-term resistance training in older people is feasible and results in increases in dynamic muscle strength, muscle size, and functional capacity.