Physical Activity as Intervention Against Age-related Loss of Muscle Mass and Function

A minimum of 450 healthy individuals (62-70 years old) will be recruited. Each individual will be randomized into one of three groups stratified according to gender (M/F), BMI (≤28/\>28), and 30 sec chair stand (≤11/\>11). The three groups are Heavy resistance training (n=150), moderate intensity training (n=150), and control (n=150, no training). Assessments will be performed at baseline, after 12 months of intervention. Furthermore, follow up will be performed after 2,4,7, and 10 years. The primary outcome is change in leg extensor power after the intervention and during follow up. The primary hypothesis is that by applying the intention-to-treat analysis, the moderate intensity training group will increase leg extensor power just as much as the heavy resistance training group. The two training groups will increase muscle power more than the control group.