Skeletal Muscle Adaptations to Training
Skeletal muscle adaptations to exercise training and the improvement in muscle force production can be related to changes which occur within the muscle and/or the nervous organization of muscle contraction. Specifically, improvements in muscular strength are the result of structural changes in muscle and are due to neural adaptations that typically account for strength gains during the early part of training. Increases in skeletal contractile proteins and anaerobic capacity are examples of muscle structural changes that occur with resistive training.
Training Responses of Older Individuals
Early studies involving the ability of older people to adapt to resistive exercise indicated that 12 to 26 weeks of resistive exercise training elicited only minimal improvements in muscle strength of men and women between the ages of 60 and 75 years. Recently, muscle rehabilitation programs for well, older populations have shown significant increases in muscle strength, muscle volume, and other parameters of muscle structure and function. Studies have documented that, given an adequate training stimulus, older men and women show similar or greater strength gains compared to young individuals after resistive training.
It has been suggested that lack of muscle loading could contribute to muscle atrophy in the aged since individuals aged 60-90 years can increase/maintain muscle mass with resistance training. Men, who are 70 years of age who have resistance-trained since 50 years of age, had muscle cross-sectional area and strength comparable to a group of 28-year-old sedentary subjects. These findings were also compared with three groups of 70-year-old subjects (sedentary controls, swimming trained, or running trained) who all had a 20-24% decrease in muscle cross-sectional area and strength.