Effect of protein and creatine supplementation during resistance training on muscle mass, strength, and muscle protein degradation in older males

Abstract

The purpose of this thesis was to determine whether nutritional supplementation combined with resistance training could maximize muscle accretion and strength in older men and whether these interventions could eliminate deficits in muscle mass and strength compared to young men. To achieve this purpose, a series of studies were performed. In the first study, the purpose was to determine differences in muscle mass, strength, and power in upper and lower body muscle groups in young and older men. These findings would determine which muscle groups were more negatively affected with age and whether nutritional supplementation and resistance training in older men could eliminate these deficits in muscle mass and strength compared to young men. Results showed that lower body measures of muscle mass, strength, and power, especially at fast velocities, is reduced more than upper body measures in older men. In the second study, the purpose was to determine the effects of protein supplementation immediately before and after training sessions for 12 weeks in older men (59-76 years), and whether this intervention could eliminate deficits in muscle mass and strength compared to young men from the first study. It was hypothesized that protein ingestion immediately before training would increase lean tissue mass and strength over protein ingestion immediately after training. Twenty-nine older men were randomized to supplement with protein or receive placebo. Results showed that the timing of protein supplementation, either before or after resistance training, had no effect on lean tissue mass, muscle thickness or strength. At the end of the study, the older group still had lower lean tissue mass, muscle thickness of the knee extensors and flexors and ankle plantar flexors, and bench press strength compared to young men; suggesting that a longer intervention in required. In the third study, the purpose was to determine the effects of creatine and protein supplementation during resistance training in older men. In addition, these results, combined with the results of 17 subjects from the second study, would determine if 22 weeks of resistance training could eliminate remaining deficits in muscle mass and strength compared to young men. It was hypothesized that creatine and protein together would increase muscle mass and strength over creatine supplementation and placebo during training. Older men (59-77 years) were randomized to receive creatine and protein, creatine, or placebo on training days (i.e.3x/week) during 10 weeks oftraining. Subjects who supplemented with creatine experienced greater gains in total muscle thickness (p