We investigated whether exercise-mediated acquisition of muscle mass and strength would occur in a concurrent manner in older adults.

A total of 152 community-dwelling older adults (young-old aged 65-74 years, old-old aged >75 years) were allocated into either 8-week comprehensive exercise training or the control group. Participants (n = 136) completed all pre- and post-intervention testing visits (young-old n = 73, old-old n = 63). Older adults in exercise groups were subjected to a series of programmed elastic band and free exercises twice per week at three to five sets of 15-20 repetitions. Body composition, skeletal muscle mass, knee strength (extensors and flexors) and gait-related physical function were evaluated as main variables.

As expected, muscular mass and knee strength (both extensors and flexors) were inversely correlated with age in the old-old group (all P < 0.001). However, knee extensor strength was the only lower limb component inversely correlated with age in the young-old group (P < 0.043). Knee extensor strength was significantly increased by exercise training in both the young-old and old-old groups (young old P < 0.042, old-old P < 0.011). Training-induced muscle hypertrophy was observed only in the young-old group (P < 0.025). The correlation of knee extensor strength against gait-related physical function was the greatest, followed by knee flexor strength and muscle mass.