Greg Roberts1; Ross Henson1; Josiah Belzer1; Katie Friese1; Ethan Jaeger1; Alan Ward1; Kyle Whitcher1; Zack Treat1; Jared Stumpe1; Brian Snyder1

1Truman State University, Kirksville, Missouri

Consistent ingestion of protein after resistance exercise has been demonstrated to increase muscle anabolism and strength with resistance training. Whey protein supplements are commonly consumed post-exercise; however, dairy milk which offers protein, carbohydrates, and other nutrients may provide additional benefits. PURPOSE: We assessed the effects of post-exercise chocolate flavored dairy milk (CM), whey protein supplement (WP), or placebo beverage (PLA) on changes in strength and body mass during 14 weeks of resistance training. METHODS: Thirty-three moderately resistance-trained males (80.4 ± 13.0 kg; 23.6 ± 6.7% Body Fat) completed baseline DXA, body weight, and 1RM for bench press (BP) and leg press (LP) assessments prior to engaging in a 3 times per week resistance training program. In a double-blind design, volunteers were randomly assigned to either CM (590 mL, 406 kcal, 20g PRO, 6.25g FAT, 67.5g CHO; n = 11), flavor-matched WP dissolved in water (590 mL, 127 kcal, 24g PRO, 1g FAT, 3g CHO; n = 11, or non-nitrogenous flavor-matched PLA beverage that was matched calorically to the CM (590 mL, 400 kcal, 0g PRO, 6.5g FAT, 85g CHO; n = 11) to consume immediately after training 3 times per week. Measurements were repeated at 7 and 14 weeks.RESULTS: Using a mixed model ANOVA, all groups increased strength as 1RM BP from baseline to post-test (p < 0.01 CM: 9.5 ± 6.3 vs. WP: 8.5 ± 6.5 vs. PLA: 5.2 ± 3.4 kg) as well as 1RM leg press (p < 0.01 CM: 51.9 ± 25.5 vs. WP: 67.8 ± 23.0 vs. PLA: 50.2 ± 26.9 kg) with no significant differences between groups. Changes at week 14 in lean mass (p < 0.01 CM 1.0 ± 0.9 vs. WP 1.8 ± 2.0 vs. PLA + 0.9 ± 1.5) and fat mass (p < 0.05 CM -0 .4 ± 1.8 vs. WP -1.6 ± 2.5 vs. PLA -0.5 ± 2.2) demonstrated no significant differences between groups. Body weight changes at week 14 were not significantly different (CM 0.8 ± 2.2 vs. WP -0.3 ± 3.1 vs. PLA 0.0 ± 2.7). CONCLUSION: The addition of 20g protein as chocolate dairy milk or a whey protein supplement containing 24g protein did not have a statistically significant effect on muscle strength or body composition changes after 14 weeks of resistance training compared to a calorie matched protein-free control beverage in a sample of moderately resistance trained young males Consistent resistance training for 14 weeks was a potent stimulus for gains in strength as measured by 1RM bench press and leg press.

ACKNOWLEDGEMENTS: This study was supported by a Grant in Aid of Student Research from Truman State University and milk was provided by The St. Louis District Dairy Council.

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