Journal of Strength and Conditioning Research, 2006, 20(4), 962-970 © 2006 National Strength & Conditioning Association BODY COMPOSITION AND PHYSICAL PERFORMANCE DURING A NATIONAL COLLEGIATE ATHLETIC ASSOCIATION DIVISION I MEN'S SOCCER SEASON RICARDO SILVESTRE,' WILLIAM J. KRAEMER,^ CHRIS WEST,^ DANIEL A. JUDELSON/ BARRY A. SPIERING,' JAKOB L. VINGREN,' DISA L. HATFIELD,' JEFFREY M. ANDERSON,' AND CARL M. MARESH^ 'Human Performance Laboratory, Department of Kinesiology, University of Connecticut, Storrs, Connecticut 06269; -Athletics Strength and Conditioning, University of Connecticut, Storrs, Connecticut 06269. ABSTRACT. Silvestre, R., W.J. Kraemer, C. West, D.A. Jedelson, B.A. Spiering, J.L. Vingren, D.L. Hatfield, J.M. Anderson, and CM. Maresh. Body composition and physical performance dur- ing a National Collegiate Athletic Association Division I men's soccer season. J. Strength Cond. Res. 20(4):962-970. 2006.—The purpose of this study was to examine changes in body composi- tion (BC) and physical performance tests (PT) resulting from a competitive season in soccer. Twenty-five male collegiate players (age = 19.9 ± 1.3 years; height = 177.6 ± 6.4 cm; body mass = 77.6 ± 8.6 kg, and percentage body fat = 12.8 ± 5.2%) were tested before (PRE) and afler (POST) the 2003-2004 National Collegiate Athletic Association season. The following tests were performed: BC (anthropometric and dual energy x-ray absorp- tiometry measurements), vertical jump (VJ), 9.1-m (9 m) and 36.5-m (36 ml sprint, lower-body power (LP), total body power (TP), and cardiorespiratory endurance (Vo^max). Training was divided into soccer-specific training: field warm-up drills, prac- tices, games, and additional conditioning sessions. A daily, un- planned, nonlinear periodization model was used to assign ses- sion volume and intensity for strength sessions (total repetitions <96 and workload was 3:80% of 1 repetition maximum). For the entire team, body mass significantly increased by 1.5 ± 0.4 kg from PRE to POST due to a significant increase in total lean tissue (0.9 ± 0.2 kg). Regionally, lean tissue mass significantly increased in the legs (0.4 ± 0.0 kg) and trunk (0.3 ± 0.1 kg). Physical performance variables were very similar for the entire team at PRE and POST; VJ (cm) = 61.9 ± 7.1 PRE vs. 63.3 ± 8.0 POST, 9.1-m (s) = 1.7 ± 0.1 PRE and POST, 36.5-m (s) = 5.0 ± 0.2 PRE and POST, predicted Vo.max (ml kg min ')= 59.8 ± 3.3 PRE vs. 60.9 ± 3.4 POST. The only significant improve- ments across the season were for TP (17.3%) and for LP (10.7%). In conclusion, soccer athletes who begin a season with a high level of fitness can maintain, and in some cases improve, body composition and physical performance from before to after a competitive season. A correct combination of soccer-specific prac- tices and strength and conditioning programs can maintain and develop physical performance, allowing a soccer athlete to per- form optimally throughout pre-, in-, and postseason play. KEY WORDS, starters, nonstarters, DEXA, conditioning, strength training INTRODUCTION m he importance of body composition in soccer performance remains unclear; however, it is a primary concern in conditioning programs throughout a season at all levels of competition. The inherent physical stress of practice sessions and com- petition during a season may modulate body composition (13). Strength and conditioning programs for soccer re- quire the development of aerobic capacity, strength, pow- er, speed, and speed endurance (17), as well as the pro- motion of specific adaptations designed to improve per- formance (15). The effects of soccer training on oxygen consumption (2, 3, 19, 33), anaerobic power (14, 24), mus- cle strength (20, 21), immune function (26), and hormonal responses (6, 9, 11, 17) during a season have been de- scribed previously. In contrast, body composition changes have been studied using error-prone methods or have been completely ignored. An increased focus on this var- iable is essential. The relationship between body composition and phys- ical performance changes are also of great interest to strength and conditioning specialists. It can be hypothe- sized that changes in body composition and physical per- formance may occur from the start to the end of a soccer training and competitive season. It was reported else- where (17) that soccer players who enter a season with a high catabolic metabolic status can experience reductions in performance during a competitive season paralleled with detrimental changes in body composition. Addition- ally, the demands of a soccer season may manifest them- selves differently in starters (S) and nonstarters (NS). In the same study (17), differences in responses to season training demands were observed between these two sub- sets of players. Fatigue or strategy changes during the course of a game require substitute players to be prepared to replace starting players with minimal decrease in team performance. Theoretically, differences in playing time or practice load between S and NS may result in measurable differences in physical characteristics. Therefore, the purposes of this study were (a) to mea- sure changes in body composition and performance in standardized, soccer-relevant physical tests that occur during a National Collegiate Athletic Association Division I soccer season and (b) to determine possible differences between S and NS during this same time frame. We hy- pothesized that, at worst, no changes in physical perfor- mance would occur from pre- to postseason. We also ex- pected to observe positive changes in body composition in the same period and to detect no differences in the vari- ahles of interest between S and NS from pre- to postsea- son. METHODS Experimental Approach to the Problem This longitudinal investigation evaluated body composi- tion and performance characteristics of Division I colle- 962