Date of Award

Summer 6-19-2014

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Nutrition

First Advisor

Dr. Dan Benardot

Second Advisor

Dr. Anita Nucci

Third Advisor

Dr. Walt Thompson

Abstract

Title: The Relationship between Moderate, Within Day Protein Intake and Energy Balance on Body Composition of Collegiate Sand Volleyball Players Background: Achieving an ideal body composition with relatively low fat mass and relatively high fat-free mass (FFM) is desirable for virtually all competitive athletes. Some studies suggest that protein intake, depending on quality, amount, and timing, may improve relative musculature by stimulating muscle protein synthesis, but some issues related to timing and amount of protein intake remain unclear. Current evidence suggests that frequent consumption of moderate amounts of protein is useful for muscle building. Purpose: The purpose of this study was to simultaneously assess energy balance and protein intake to determine if these factors are associated with body composition in a population of collegiate sand volleyball players. Methods: In a cross sectional, observational study, players completed a food intake and activity form for a 24-hour period to serve as the basis of energy balance and protein intake assessment. The assessment day was representative of a typical day during the regular training season. These data were entered into a software program providing total and hourly energy balance and nutrient content of the consumed foods. Athletes were measured for body composition via a multi-current bioelectrical impedance scale to predict weight, BMI, fat mass and fat free mass. Height was measured using a standard wall-mounted stadiometer. Data analyses included descriptive and frequency statistics, Spearman correlations and regression analyses. Results: Twelve women from the GSU sand volleyball team participated in the study using an IRB-approved protocol. The mean BMI was 22 kg/m2 (±3 kg/m2) and the mean body fat percentage was 18% (±7%). The mean protein intake for all participants was 132 grams (±52 g). Protein intake distribution was skewed, on average, toward the latter half of the day with approximately 19% of protein consumed in the morning and 34% consumed in the evening. The mean net energy balance at the end of the 24-hour assessment period was -404 (±385) kcal. Athletes, on average, spent 17 hours in a catabolic energy balance state (< 0 kcal). No significant correlation was found between energy balance per gram of protein consumption and body composition. However, regression analyses indicated that energy balance and protein variables explain a significant proportion (p=.037) of the variance in body fat percentage. Conclusions: Sand volleyball players in this study spent a high proportion of time in a negative energy balance, which may have compromised the potential benefit that frequent protein consumption may have had on FFM. Since both energy balance and protein explain a significant proportion of the variance in body composition, these athletes might benefit from improving within-day energy balance as a strategy for optimizing body composition.

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