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Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)


Health and Nutritional Sciences

First Advisor

Matthew Vukovich


Purpose: This study was designed to track the changes in body composition of college football players before and after a 14-week competitive season while tracking diet changes. The first hypothesis of this study was that collegiate football players would decrease muscle mass and increase their body fat percentage from before to after the season. The second hypothesis was that caloric intake would be greater after the season than before the season.
Methods: Body compositions of 53 NCAA Division I football players from South Dakota State University (20 ± 1 years) were tested pre and post season using a DXA. Body mass, lean mass and fat mass were all evaluated. Subjects completed a 3-day diet record at both testing times, pre and post season. All measures were statistically analyzed for pre-post season differences. The players were looked at as a whole as well as broken down into two different groupings: linemen vs. non-lineman (skill) and upperclassmen (juniors and seniors) vs. lowerclassmen (freshmen, red-shirt freshmen, and sophomores).
Results: Significant changes in body mass and lean mass were observed over the course of the season for all participants. Body mass declined significantly 1.2% during the 14 week season. The change in body mass (1.7 ± 3.2 kg) was due to a significant decline (1.7 ± 2.3 kg) in lean mass. Fat mass did not change during the course of the season. The significant loss in lean mass was observed in the arms, legs, and trunk. There were differences at baseline between linemen and skill players. Linemen were heavier, had more lean and fat mass than those classified as skill players. During the football season, both linemen and skill players experienced significant changes in body composition. Linemen lost 1.7 ± 2.8 kg of mass and 1.9 ± 1.7 kg of lean mass. Linemen did not experience any change in body fat. Skill players also experienced a significant decline in mass (0.8 ± 2.8 kg) and lean mass (1.0 ± 1.8 kg). The decline in lean mass was greater (p=0.06) for linemen compared to skill players. Regional changes demonstrate that lean mass is lost similarly in the arms, legs, and trunks for linemen but only the legs for skill players. There was no difference between upper- and lower-classmen in body composition measurements at baseline. However, upper-classmen experienced significantly greater changes in body composition compared to lower-classmen. Upperclassmen experienced a decline in body mass of 2.3 ± 2.7 kg and lean mass declined 1.9 ± 1.6 kg. Fat mass significantly increased in the lower classmen (0.9 ± 1.7 kg) but did not change in the upper-classmen. Upper-classmen experienced significant declines in arms, legs, and trunk lean mass, while lower-classmen experienced significant declines in lean mass in the legs and trunk. The macronutrient composition of the diet was not different from pre-season to post-season.
Conclusion: The results of this study indicate the body composition, specifically body mass and lean mass, of collegiate football players changes significantly from preseason to post-season. Significant differences were also observed when comparing both linemen and skill players and upper- and lower-classmen, respectively. The macronutrient composition of the diet was not different from pre-season to post-season but appears to be inadequate in energy and protein consumption. These findings, showing a significant decline in body mass accompanied with a significant decline in lean mass, point toward a potential decrease in performance based on current research.

Library of Congress Subject Headings

Football -- Physiological aspects.
Body composition.
College football players.


Includes bibliographical references (pages 39-43).



Number of Pages



South Dakota State University


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