Date of Award


Degree Type


Degree Name

Master of Science in Kinesiology



First Advisor

Disa L. Hatfield


In addition to the physical aspects of training, young athletes are also mirroring the nutritional and supplementation practices of adult athletes. While research on the use of supplements among adult athletes is well known, few studies on supplement use by teenage athletes exist. Research has reported that between 22.3% to 71% of high school athletes use some form of supplementation, with whey protein being the most common. Despite the popularity of whey protein among teenage athletes, knowledge regarding its effects on health and performance in teenage athletes is currently insufficient. Therefore, the purpose of this study was to assess the safety of whey protein supplementation in relation to biomarkers of kidney functioning. A secondary purpose of this study was to investigate the effects of whey protein supplementation on body composition and athletic performance in teenage athletes. Ten healthy teenage participants (five boys and five girls) were matched according to body mass, height, tanner stage, age, and strength, and separated and randomly assigned in a double blind manner to either a 24g/d whey protein group (WP) (n = 5; age: 16 ± 1 y; Tanner: 4.2 ± 0.8; Height: 1.7 ± 0.1 m; Mass: 78.6 ± 23.4 kg; BF: 23.3 ± 11.2 %) or a 27 g/d carbohydrate control group (CG) (n = 5; age: 15.2 ± 1.6 y; Tanner: 4.6 ± 0.9; Height: 1.7 ± 0.1 m; Mass: 69.8 ± 15.4 kg; BF: 20.5 ± 10.1 %). Participants consumed their given supplement daily for four weeks. Biomarkers of kidney health, assessed via urinalysis, were collected at pre and post. At baseline and post, participants underwent athletic performance tests consisting of 1RM squat and bench press, vertical jump, and 5-10-5 agility run, and body composition testing. One-day diet logs were completed at baseline and post. Diets were analyzed for mean calorie, carbohydrate, protein, and fat intake. Participants were considered free-living and continued with their individual sport and resistance training programs. Baseline dependent variable differences between groups were compared using independent samples t-tests. Differences in athletic performance measures, body composition, and urinalysis measures were analyzed by a two-way mixed factorial (ANOVA). Significance was set at p ≤ 0.05 and values are presented as mean ± SD. There were no baseline differences (p ≥ 0.05) in age, height, tanner stage, body mass, vertical jump, 5-10-5 pro agility run, squat 1RM, bench press 1RM, PBF, LBM, BMD, or any urinalysis measure. Additionally, no baseline differences (p ≥ 0.05) were observed for mean calorie, carbohydrate, protein, or fat intake. No main effect (p ≥ 0.05) for time was revealed for VJ, 5-10-5 pro agility run, squat 1RM, or any body composition or urinalysis measure, but was revealed for bench press 1RM (p = 0.003). However, there was no group X time interaction was observed for any athletic performance, body composition, or urinalysis variable (p ≥ 0.05). To the best of our knowledge, this study is the first of its kind investigating the effects of whey protein on health and performance in teenage athletes. Results of this study suggest that short-term whey protein supplementation in a healthy teenage athlete population has no negative effect on biomarkers of kidney health. Therefore, researchers should now feel safe conducting whey protein supplementation protocols in a teenage population, utilizing longer intervention periods (i.e. ≥ 8 weeks), with the goal of eliciting positive changes in body composition and athletic performance.



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