Effects Of Whey Protein And Casein Supplementation On Training-induced Adaptations In Older Males

PURPOSE: To examine the chronic effects of whey and casein protein supplementation in conjunction with supervised resistance-training on muscle strength and body composition in older males. METHODS: Thirty-six non-resistance trained males (62.5±6.8 yrs, 177±6.32 cm, 95.25±16.9 kg) were randomized in a double blind manner to ingest either whey protein (WP) [20g/d WP + 5g carbohydrate (CHO)], casein (CAS) [20g/d CAS + 5g CHO] or maltodextrose placebo [25g/d CHO] while participating in a supervised high-intensity resistance training program (3 sets × 10 repetitions at 75% of 1 repetition maximum (RM)), 3 days per week for 12 weeks. Testing sessions were completed prior to 0 weeks, 4 weeks, 8 weeks and 12 weeks post resistance training and supplementation. Each testing session included body composition measurement as determined by Dual Energy X-Ray Absorptiometry and muscle strength measurements as determined by 1 RM on leg press and bench press. Data was analyzed using repeated measures ANOVA. RESULTS: A significant time effect was observed for 1 RM bench press (0 weeks: 59.06kg ± 14.38kg vs. 12 weeks: 77.51 ± 22.02kg, p<0.001), 1 RM leg press (0 weeks: 241.03kg ± 78.45kg vs. 12 weeks: 383.81kg ± 108.22kg, p<0.001) and fat free mass (FFM) (0 weeks: 60.55kg ± 9.17kg vs. 12 weeks: 61.66kg ± 8.91kg, p<0.05). A significant group × time interaction was also observed for 1 RM leg press (p = 0.001), with subsequent analysis demonstrating a trend towards significantly higher 1 RM leg press strength in the WP (413.02kg ± 108.65kg, p=0.053) and CAS (408.18kg ± 130.77kg, p=0.086) groups compared to the CHO (330.23kg ± 85.23kg) group at 12 weeks. No other group by time interactions or group effects were identified. CONCLUSION: The present study suggests that whey and casein protein supplementation in conjunction with supervised high-intensity resistance training may be important in combating sarcopenia.