Lighter weights promote strength

Maintaining muscle mass and bone health doesn’t require lifting heavy weights, assure Canadian researchers in the Journal of Applied Physiology. In a small study, volunteers were assigned to lift until exhaustion—either

75% of the maximum weight they could lift (for about 10 reps) or 30% percent of the maximum weight (25 reps); they did the reps for three sets, four times a week. After 12 weeks, all subjects gained muscle strength with no significant differences between the two groups. The authors say the key was that each lifted until exhaustion, when the cellular mechanisms in muscle tissue that cause growth are triggered.