Body Size and Composition of National Football League Players

Journal of Strength and Conditioning Research, 2005, 1913J, © 2005 National Strength & Conditioning Association BODY SIZE AND COMPOSITION OF NATIONAL FOOTBALL LEAGUE PLAYERS WILLIAM J. KRAEMER,' J O N C. TORINE,^ RICARDO SILVESTRE,^ DUNCAN N . FRENCH,'* NICHOLAS A. RATAMESS,^ BARRY A. SPIERING,' DISA L. HATFIELD,' JAKOB L. VINGREN,^ AND J E F F S. VOLEK' 'Human Performance Laboratory, Department of Kinesiology, University of Connectieut, Storrs, Connecticut 06269: '^Indianapolis Colts Professional Football Team, Indianapolis, Indiana 46254; ''Northumhria University, Newcastle Upon Tyne, United Kingdom; ^Department of Health and Exercise Science, The College of New Jersey, Swing, New Jersey 08628. Kraemer, W.J., J.C. Torine, R. Silvestre, D.N. French, N.A. Ratamess. B.A. Spiering, D.L. Hatfield, J.L. Vingren, and J.S. Volek. Body size and composition of National Football League players. J. Strength Cond. Res. 19(3).-485^89. 2005.—The purpose of this study was to present a profile of body size and composition of National Football League (NFLl players prior to the start of the regular season. Fifty-three members of the Indianapolis Colts professional football team were measured for height, body mass, and percentage body fat using the BOD POD air-displacement plethysmography system during summer camp of the 2003 football season. These data were categorized by position for comparison with previous studies of NFL football players. The relationships observed were as follows I -^ represents nonsignificant; > represents ;; s 0.05): Height: Offensive Line = Defensive Line = Quarterbacks/Kickers/Punters = Tight Ends > Linebackers > Running Backs = Wide Receivers = Defensive Backs. Body Mass: Offensive Line ^ Defensive Line > Tight Ends = Linebackers > Running Backs ^ Quarterbacks/ Kickers/Punters > Wide Receivers - Defensive Backs. Percentage Body Fat: Offensive Line > Defensive Line > Quarterbacks/ Kickers/Punters ^ Linebackers = Tight Ends > Running Backs - Wide Receivers = Defensive Backs. Comparisons to teams in the 1970s indicate that body mass has increased only for offensive and defensive linemen; however, height and hody fat among player positions have not dramatically changed. Furthermore, the body mass index is not an accurate measure or representation of body fat or obesity in NFL players. These data provide a basic template for size profiles and differences among various positions and allow comparisons with other studies for changes in the NFL over the past 3 decades. more recent teams is needed in order to create a historical time line for NFL football players and body composition. The public perception is that current players are heavier than earlier NFL players, yet this may not he true for all positions. Factors related to rule changes and position skills may be the mediating factor for higher body mass in offensive linemen. Rule changes that eliminated posting as well as chop blocking in the line have caused the majority of offensive line play to take place above the waist after the mid 1970s. In other words, offensive line play has increasingly relied on upright body leverage and mass acceleration technique for drive blocking and quick upright shielding and positioning for pass blocking. Dramatic changes in height and body mass have been shown in Division I college players, especially in linemen; however, such relative comparisons have not heen readily available in the literature for each position for NFL players (8). Body fat is highly related to playing position of football players, as previous studies have demonstrated (4, 6, 15, 17, 18). This is because of the different speed and movement demands of each position. The purpose of this study was to examine differences among positions in body size and '/(body fat of NFL players prior to the start of the regular season. A secondary purpose was to make a descriptive comparison to previous studies in the literature by grouping the positions in a similar manner. KEY WORDH. air-displacement METHODS ABSTRACT. plethysmography, BOD POD, per- centage fat, athletics, NFL m INTRODUCTION he study of body size and composition of professional football players in the National Football League (NFL) has spanned more than 30 years (17). With improvements in strength and conditioning programs, the lay perception is that players are larger compared to players of previous decades. Although this has been shown to be true for players in the college ranks (8, 11, 12, 14), factors other than size (e.g., strength, speed, agility, and power) may be more important to playing ability at the NFL level. However, few descriptive studies are available that use quantitative analyses for body fat and percentage body fat CJf body fat) (e.g., underwater weighing) in NFL players, thus providing a further need for documentation of NFL players' body size and composition. Furthermore, an update on Experimental Approach to the Prohlem We assessed current NFL players from the Indianapolis Colts professional football team in summer training camp prior to the 2003 football season (2003 Colts record 12-4). As such, we felt that each player would be in top condition after an ofT-season conditioning program and summer minicamps. Measurements were obtained of hody height, body mass, and '/rbody fat using an air-displacement plethysmography system (BOD POD). From this, where appropriate, we made comparisons among the different positions and then descriptive comparisons with prior results in the literature. Suhjects All of the subjects were members of the Indianapolis Colts professional f'ootball team at the time of the study, prior to the start of the 2003 regular season. Each player participated in testing as a part of routine functions as mem485 486 KRAEMKK, TORINK, SII.VRSTRE ET AL. bers of the team. The project was approved by the University's Institutional Review Board for retrospective study analysis of data sets. Fifty-three members of the team participated, and data were categorized by position. TABLE 1. Mean (± SD) for body size and body composition values hy position.* Experimental Procedures RB 4 OL 11 QB 2 WR 7 4 TE LB 5 DL 7 DB 11 K/P 2 Each player's height was measured on a wall with a calibrated Lufkin tape measure, and body mass was obtained via a calibrated scale (Life Measurement Instruments, Concord, CA). Percent body fat determination was obtained using air-displacement plethysmography (AP) with the BOD POD body-composition system (Life Measurement Instruments) using the basic methods previously described (19). Briefly, the AP system consists of a computer-integrated, dual-chambered air plethysmograph, digital weight scale, and BOD POD software version 1.69. The BOD POD is a dual-chamber single unit with an electronically controlled diaphragm. The function of this diaphragm is to cause volume and pressure perturbations between the 2 chambers, the front test and the rear reference chamber. Fluctuations in the pressure are used to calculate chamber volume. Prior to every testing session, the BOD POD was calibrated, and the test was fully explained to each player. A 2-point chamber calibration was used, 1 with the chamber empty and the other with a 50-L calibration cylinder. A regression equation was then generated by the system to calculate the relationship between unknown volumes and ratios of known pressure amplitudes. Each subject wore tight-fitting shorts (Stromgren Supports Inc., Hays, KS) and a swim cap during the procedure. Subjects were asked to sit in the BOD POD in an erect posture and with hands folded in their laps for body volume measurement. Subjects were instructed to sit quietly with normal respiration cycles and not to move. A raw hody volume was measured until 2 values within a range of 150 ml were obtained (3). After the volume measurement, subjects were instructed to use the internal breathing circuit for measurement of thoracic gas volume. Thoracic gas volume was estimated through the panting maneuver (7, 10). Statistical Analyses The data are presented as mean ± SD. Pearson productmoment correlation analyses were performed between body composition and body mass index (BMI). Independent ^tests with alpha level corrections (to maintain alpha at 0.05) were used to determine differences between positions. Quarterbacks were combined with kickers and punters in quantitative analyses. Qualitative descriptive mean comparisons were made with previous study findings, because no statistical evaluation was performed. Positions were grouped according to the design of prior studies for rank comparisons. An alpha value ofp ^ 0.05 was defined as significant in this investigation. RESULTS In this study, we investigated a professional football team during summer camp prior to the actual NFL season. Height, body mass, and '.^body fat for the different positions are presented in Table 1. Tbe following relationships were observed among the various positions. (= indicates nonsignificance; > indicates p s 0.05). Position n Height (cm) 180.0 193.3 192.0 180.5 194.4 186.9 191.6 179.7 191.4 ± ± ± ± ± ± ± ± ± 3.0 3.8 5.8 3.9 4.0 2.6 2.5 4.5 5.9 Body mass (kg) 96.5 140.0 104.2 85.6 115.6 107.8 126.8 87.1 95.3 ± ± ± + ± ± ± ± ± 8.1 7.5 2.6 6.5 7.2 2.9 2.4 5.6 0.0 9f Fat 7.3 25.1 14.6 8.1 15.1 15.7 18.5 6.3 11.4 ± ± ± ± ± ± ± ± ± 7.3 2.5 9.3 2.8 5.4 2.8 3.8 2.8 8.3 BMI 29.8 37.1 28.3 26.3 30.6 30.9 34.6 26.9 26.0 ± ± ± ± ± ± ± ± ± 2.7 1.9 2.4 2.0 0.9 0.6 1.4 1.6 3.4 * BMI = body mass index; RB = running back; OL = ofFensive line; QB ^ quarterback; WR = wide receiver; TE = tight end; LB = linebacker; DL = defensive line; DB = defensive back; K/ P - kicker/punter. TABLE 2. Health status by BMI and percentage fat criteria and correlations between body composition compartments and BMI^ Position RB OL QB WR TE LB DL DB K/P BMI Obese Severely obese Overweight Overweight Ohese Ohese Ohese Overweight Overweight Percentage fat Healthy Poor Healthy Healthy Healthy Healtby Good Healthy Healthy Body compartment Total mass Total lean mass Total fat mass Pecentage fat BMI 0.957t 0.870t 0.907-i0.856t ^ • ' BMI - body mass index; RB = running hack; OL = ofTensive line; QB - quarterback; WR ^ wide receiver; TE = tight end; LB = linebacker; DL = defensive line; DB = defensive hack; K/ P = kicker/punter, t - p ^ .05 1. Height Offensive Line = Defensive Line = Quarterhacks/Kickers/Punters = Tight Ends > Linebackers > Running Backs = Wide Receivers = Defensive Backs 2. Body Mass Offensive Line = Defensive Line > Tight Ends = Linebackers > Running Backs = Quarterback s/Kickers/Punters > Wide Receivers ^ Defensive Backs 3. Percentage Body Fat Offensive Line > Defensive Line > Quarterbacks/Kickers/Punters = Linebackers ^ Tight Ends > Running Backs ^ Wide Receivers ^ Defensive Backs We were also interested in the relationship between BMI and values of %hody fat found hy the BOD POD, with the 2 descriptions of "health status" based on cut-off values from both variables. Also, the correlations between the different compartments of body composition and BMI were calculated with r values considered strong and significant (Table 2). Figures 1, 2, and 3 present the data from this study for qualitative comparisons to previous studies of NFL players using hydrostatic weighing (HW) at different points in time. Wilmore and Haskell (17) examined 44 professional NFL players representing a total of 5 teams NFL AND BODY COMPOSITION Te tE 9a prHint iludt 9a pmsnl itudy 487 itt • VMniore & Ha^ketl 1972 VAmoieSHEiskell 1973 • \nfllmore S Hoskell 1976 Vifllmore a Haskell 1976 • Srowtflal 199B Snow el 9l 1998 • Kraemet et al ptesenl stutfy • Kraemer et al piesenl study 72 3. The percentages of hody fat of National Football League players hy position from previously published studies and from the current study are presented for comparative purposes. Each of these studies used underwater weighing, hut the current study used BOD POD methodology. FIGURE FIGURE 1. The heights (cm) of National Football League players by position from previously published studies and from the current study are presented for comparative purposes. 7B 9B prat a m i in the American and National Foothail Conferences. Suhjects were divided into 5 categories, as shown in Figures 1 through 3 and Tahle 2. In 1976, Wilmore et al. (18), using the same category of position groups, determined values for 164 NFL players, and Snow et al. (15), in a study with the Atlanta Falcons, measured 36 players (however, in this study quarterbacks were not included in the offensive hack/wide receiver category). These studies examined values for height, body mass, and '/rbody fat, where the latter was calculated from HW. Presented in Table 2 are the 3 studies mentioned previously, as well as data from a 1979 study with 51 NFL players, with values reported for height, hody mass, and 9; body fat, but with a slightly different player position arrangement (6). Hence, Table 3 presents the numerical data of studies of NFL players for further comparison to the present study data set. DISCUSSION 7! '1 1973 • IMHtnore S HaskeB 1976 • Snow el al 1998 • Hraemer el al present FIGURE 2. The hody masses (kgl of National Foothail League players by position from previously published studies and from the current study are presented for comparative purposes. The most dramatic increases in body mass compared to the 1970s were observed in offensive and defensive linemen. However, height has essentially remained unchanged except for defensive hacks for more than 30 years (see Figure 1 and Table 3). This is interesting, hut it must be remembered that only the best college players are drafted into the NFL, and basic body structure as related to height appears to remain unchanged. Significant changes may have occurred from the 1950s to the 1970s in this parameter. With rule changes in drive blocking style as well as tbe changes in tbe use of the extended arms and hands for pass blocking, offensive line play has moved above the waist. Theoretically, this has reduced restriction of hody mass needed for such "old school" blocking methods (now 488 KRAEMKR, TORINE, SILVESTRE ET AL. TABLE 3. Mean (± SD) for body composition values by position in professional Annerican football players.''^ Study Positions Wilmore and Haskell (1972) (17) DB OBAVR LB OL/TE DL DB OB/WR LB OL/TE DL DB/WR OB LB/TE OL/DL DB OB/WR LB OL/TE DL Height (cm) Body mass (kg) 184.4 184.2 189.7 193.5 192.2 182.5 183.8 188.6 193.0 192.4 173.4 183.0 189.2 191.2 185.9 ± 3 .3 179.9 ± 5 .1 186.8 ± 3 .1 194.1 ± 3 .9 192.0 ± 3 .4 85.0 91.8 107.6 113.2 120.6 84.8 90.7 102.2 112.6 117.1 83.6 90.7 103.8 117.6 93.7 ± 5.6 95.5 ± 17.8 113.1 ± 8 .0 135.7 ± 13.4 126.8 ± 8,,7 % Fat (HW) 7.7 8.3 18.5 15.5 18.7 Wilmoreet al. (1976) (18) 9.6 9.4 14.0 15.6 18.2 Gleim(1984)(6) 5.7 9.6 12.5 17.0 Snowet al. (1998) (15) 5 10 .7 ± 1.4 6 12 .6 ± 4.8 4 15 .3 ± 2.6 16 24.7 ± 4.7 5 20 .3 + 2.9 "'• HW = hydrostatic weighing; DB = defensive back; OB = offensive back; WR = wide receiver; LB = linebacker; OL ^ offensive line; TE = tight end; DL = defensive line. 4 10 6 12 12 26 40 28 38 32 illegal) as scramble blocks, spearing, and posting witb cbop blocks. Depending upon the offensive style, plays requiring pulling, cross-blocks, change-ups in pass blocking, and no buddle offenses may cause differences in body mass among various NFL teams. In addition, tbe extent of nutritional interventions may also play an important role. Qualitative comparisons between data from tbe Atlanta Falcons (15) and tbe current data from tbe Indianapolis Colts may support this contention. Tbe Colts offensive and defensive lines had a lower %body fat than tbe 1998 Falcons, implicating potentially different styles of play, conditioning programs, or nutritional interventions. Defensive linemen may be lighter than offensive linemen on average because of tbe requirements for greater movement abilities to play wider bole coverage zones and for pass rusbing. Nevertheless, tbe body mass increases are also reflected in tbe defensive line over the past 3 decades. Surprisingly, these changes are different in college football, especially at tbe Division I level, wbere height and body mass profiles have dramatically increased over tbe past 30 years (8, 11, 12). Offensive-defensive position "mirroring" reflects tbe obvious offensive and defensive play interactions. Typically, offensive and defensive linemen have matched each other for height, body mass, and %body fat. Linebackers (LB) "mirror" tigbt ends (TE) and running hacks (RB), and in tbis study, they were equal in body mass (LB-RB) and %body fat (LB-TE). In this study, defensive backs and wide receivers were similar in height, body mass, and %body fat, suggesting t h a t position "mirroring" holds true. Recent strategies over the past several years to break tbis "mirror effect" bave been observed with tbe use of large wide receivers intended to create mismatches witb defensive backs. A recent report suggested a high prevalence of obesity as measured by BMI in professional football players (researcb letter in JAMA 293:1061-1062. 2005). However, these data, being based solely on BMI calculations from body mass and weight posted in tbe NFL Web site, may not accurately portray the modern player regarding health status, because BMI calculations do not distin- guish between fat and lean tissue. Despite the significant correlation between the variables of body composition and BMI, a purely associative value is of little help in determining magnitude, because of the composite fat and lean tissue components integrated in the BMI measurement. In highly trained football players, this allows for dramatic overstatements regarding health status. In our study we can observe that, regardless of the fact t h a t the average for BMI in all positions shows athletes to be overweight or obese, wben percentage fat is taken into consideration, athletes are considered to he healthy or in "good" health, and this only takes into consideration one dimension of health status. Our results make a case for tbe importance of measurement of lean tissue, because these athletes are considered to he at risk hy BMI standards, but tbis appears to he a case of "false positives." Tbe only exception was observed with the offensive line, where values for BMI were higher, accompanied with the classification of "poor" in health estimation, but the %body fat still did not represent extreme values as noted hy the BMI. No m a t t e r what the population, there is a need for further investigation to go beyond the BMI wben attempting to understand populations a t risk with regard to body mass and health status. Thus, more direct testing methods are warranted. With the strict nutritional counseling seen in this study, associated with a comprehensive strength and conditioning program, such concerns may be minimized and ultimately performance enbanced. Recent researcb has focused on the differences and similarities between BOD POD air pletbysmograpby (AP), bydrostatic weigbing (HW), and dual energy x-ray absorptiometry (DEXA). In a study with 69 Division IA football players, Collins et al. (2) measured body density (BD) using AP, HW, and DEXA. Tbe authors concluded t b a t BD measured using the AP was higher t h a n the criterion HW, t h u s yielding lower %body fat scores. In another study with multiple comparisons between methods (AP, HW, and DEXA), %hody fat demonstrated high correlations (r > 0.90, p < 0.0001) between methods (9). In a study by Weyers et al. (19), significant correlations accounting for a high degree of the shared variance between NFL AND BODY COMPOSITION DEXA and AP ir = 0.98 to 0.99) for %body fat, fat mass, and fat-free mass were demonstrated; however, results were significantly different in estimating tbe same variables, with the AP estimate of '/rhody fat and fat mass being lower. Direct comparisons between AP and DEXA showed tbat, in 62 wbite men, %body fat was systematically underestimated wben measured by AP (13). Similar results were found in anotber study witb healthy men (n = 23), wbere AP was compared to HW (1). However, in a black population, Wagner et al. (16) found that %body fat estimated from AP, HW, and DEXA differed significantly (p < 0.01) and that AP significantly and systematically underestimated BD, resulting in an overestimation of %body fat. Despite tbe relationsbip between AP and other methods of body fat measurement presented above, results from this study showed that measurements of %body fat for offensive and defensive linemen were significantly higher than for other positions. Again, the expected position hierarchy was observed in 7rhody fat, where quarterbacks, kickers, linebackers, and tight ends bad similar results, and tbis value was significantly greater than the value for running hacks, wide receivers, and defensive hacks. In general, linebackers appear to have become leaner; this may he due to a greater emphasis on the passing game and changes in pass coverage responsibilities over tbe years. With heights similar over the years, and witb body mass increasing for linemen, future studies need to profile comparisons of strength, power, speed, agihty, and nutritional behaviors of NFL players within a team, between teams, and over the past decades, if possihle, to better understand the changes in the position requirements as well as the changing demands of the professional football game. 2. REFERENCES 1. BlAGGi, R.R., M.W. Voi.LMAN, M.A. NiES. C.E. BRENER, P.J. FLAKOLL, D.K. LKVENHAGEN, M. SUN, Z. KARABL'LL:T, ANO K.Y. CHEN. Comparison of air-dispiacement pletbysmography with hydrostatic weighing and bioelectrical impedance analysis for the assessment of body composition in healthy adults. Am. J. CUn. Nutr. 69:898-903. 1999. COLLINS, M.A., M.L. MILLARD-STA^• 'FORD , P.B. SPARLING. T.K. SNOW, L.B. ROSSKOPF, S.A. WEBB, AND J. OMER. Evaluation of the BOD POD for assessing body fat in collegiate football players. Med. Sci. Sports Exerc. 31:1350-1356. 1999. 3. DEMP.STER, P., AND S. 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PRACTICAL APPLICATIONS Interestingly, and in contrast to college comparisons over tbe years (8), body size of various NFL players has remained essentially similar; however, offensive and defensive linemen's body mass has increased, possihly due to changes in rules and team strategies. With the even greater emphasis on multidirectional speed and agility, the increase in lean body mass may be important. Tbe strengtb and conditioning specialist must deal with not only physical development (e.g., strengtb, power, and agility) but also the nutritional programs related to body composition needs. Our data create templates for body dimensions of NFL players as the starting point for further analyses. It also points out that BMI is not a proper indicator of "health status" for football players, and furtber analyses are needed to determine the health profile of an athlete. This may be especially important as players transition after their careers to a health and fitness lifestyle. 489 14. SEILER, S., M . TAYLOR, AND R. DIANA. Assessing anaerobic power in collegiate football players. J. Appl. Sport Sci. Res. 4: 9-15. 1990. 15. SNOW, T.K., M. MII.LARD-STAFP'ORD, AND L.B. ROSSKOPF. Body composition profile of the NFL players. J. Strength Cond. Res. 12:146-149. 1998. 16. WAGNF.R, D.R.. V.H. HEYWARD, AND A.L. GIBSON. Validation of air di.splacement plethysmography for assessing body composition. Med. Sci. Sports Exerc. 32:1339-1344. 2000. 17. WM.MORE. J.H.. AND W.L. HASKEI.L. Body composition and en- durance capacity of professional football players. J. Appl. Physiol. 5:564-567. 1972. 18. WiLMORK. J.H.. R.B. PARR, W.L. HASKEI.L. D.L. COSTILL, L . J . MiLBURN, AND R.K. KERIJ\N. Football pros' strengths and CV weakness charted. Phys. Sportsmed. 4:45-54. 1976. 19. WEYERS, A.M., S.A. MAZZETTI, D.M. LOVE, A.L. GOMEZ, W.J. KRAF.MER, AND J . S . VOI.EK. Compari.son of methods for assessing hody composition changes during weight loss. Med. Sci. Sports Exerc. 34:497-502. 2002. Acknowledgments The authors thank the Indianapolis Colts coaches, players, and organization for their support and participation. Address correspondence to Dr. William J. Kraemer, [email protected].