Marcas Bamman, the director of the UAB Center for Exercise Medicine at the University of Alabama at Birmingham says “Our lab and others have shown repeatedly” that older muscles will grow and strengthen"
In his studies, men and women in their 60s and 70s who began supervised weight training developed muscles that were as large and strong as those of your average 40-year-old.
But the process of bulking up works differently in older people than in the young, but practically, older muscles will become larger and stronger if you work them, Dr. Bamman says.
The key, he continues, is regular and progressive weight training. Plan on tiring yourself. In order to initiate the biochemical processes that lead to larger, stronger fibers, Dr. Bamman says, you should push your muscles until they are exhausted.
In his studies, volunteers used weights calibrated so that the lifters could barely complete a set of eight to 12 repetitions before their arms or legs grew leaden and they had to rest. They repeated each set two or three times and visited the gym three times per week. If you are new to weight workouts, ask for an orientation at your gym or consult an athletic trainer who often works with older clients.
Med Sci Sports Exerc. 2011 Jul;43(7):1177-87. doi: 10.1249/MSS.0b013e318207c15d.
Exercise dosing to retain resistance training adaptations in young and older adults. Bickel CS1, Cross JM, Bamman MM.
Resistance training (RT) is a proven sarcopenia countermeasure with a high degree of potency. However, sustainability remains a major issue that could limit the appeal of RT as a therapeutic approach without well-defined dosing requirements to maintain gains.
PURPOSE: To test the efficacy of two maintenance prescriptions on muscle mass, myofiber size and type distribution, and strength. We hypothesized the minimum dose required to maintain RT-induced adaptations would be greater in the old (60-75 yr) versus young (20-35 yr).
METHODS: Seventy adults participated in a two-phase exercise trial that consisted of RT 3 d·wk for 16 wk (phase 1) followed by a 32-wk period (phase 2) with random assignment to detraining or one of two maintenance prescriptions (reducing the dose to one-third or one-ninth of that during phase 1).
RESULTS: Phase 1 resulted in expected gains in strength, myofiber size, and muscle mass along with the typical IIx-to-IIa shift in myofiber-type distribution. Both maintenance prescriptions preserved phase 1 muscle hypertrophy in the young but not the old. In fact, the one-third maintenance dose led to additional myofiber hypertrophy in the young. In both age groups, detraining reversed the phase 1 IIx-to-IIa myofiber-type shift, whereas a dose response was evident during maintenance training with the one-third dose better maintaining the shift. Strength gained during phase 1 was largely retained throughout detraining with only a slight reduction at the final time point.
CONCLUSIONS: We conclude that older adults require a higher dose of weekly loading than the young to maintain myofiber hypertrophy attained during a progressive RT program, yet gains in specific strength among older adults were well preserved and remained at or above levels of the untrained young.