The data used in this study cover 70 years and were derived from published journal articles in which a measured body height, body weight, and body composition were reported. Regression slopes were calculated for college and professional football players for each of the dependent variables for the following playing positions: mixed linemen, mixed offensive backs, mixed skilled players, and all positions combined. The results of this study show that over time there has been a significant increase in body weight for all college football players (mixed linemen, mixed offensive backs, mixed skilled, and all positions combined) and for profession football players (mixed linemen and mixed offensive backs). The results also show that there was a significant increase in percent body fat for college football players (mixed lineman and all positions combined). The obtained results also show that there has been no significant change in body height for college level players, whereas for professional level players there has been no significant change over time in both body height and body composition.
As the game of American football has evolved at the college and professional level with a greater demand for bigger athletes, there is greater emphasis on year-round training, proper nutrition, and the desire to be as physically large as possible while still maximizing running speed and quickness. This has led football players to use year-round advanced training programs, consume nutritionally appropriate diets, and use performance enhancing ergogenic aids to increase muscle size and strength.
Physical training is an important component for the development of muscle size. Early in the history of football, there was little training performed for the specific purpose of increasing body size. Training regimens consisted of callisthenic types of activities and little formal resistance exercise training (personal correspondence with older former college and professional players). Furthermore, off-season training was often limited to a short time period before the start of the season. Over time, a transition to year-round training using exercises specifically designed to increase muscle size and strength has occurred. These new and improved programs have helped athletes increase their body weight during training. Additionally, the prevalence of professionally educated and trained strength and conditioning coaches has increased so that all college and professional football teams have individuals working in these positions. For example, the founding of the National Strength and Conditioning Association in 1978 gave rise to knowledgeable professionals helping athletes increase body size through proper training and conditioning programs. All these training factors have probably contributed to the increase in body weight and body composition.
Another factor contributing to the changes observed in body weight and body composition over time is the use of improved nutritional intake. This is especially true as it relates to adequate carbohydrate and protein intake during training (53). Numerous studies have demonstrated the importance of adequate carbohydrate and protein intake during training for the purpose of increasing body weight and muscle mass (53). Furthermore, an appropriate macronutrient intake is especially important during periods of heavy training when attempting to increase muscle mass (53).
The use of performance enhancing ergogenic aids designed to increase muscle strength and size may also be a likely contributor to the change in body weight observed among college and professional football players. Several ergogenic aids have been shown to significantly increase body weight and muscle mass: creatine (56), beta-hydroxy-beta-methylbutyrate (36), and anabolic steroids (21). In particular, anabolic steroids, when combined with a resistance exercise training program, result in an increase in body weight and muscle mass (16,21,37). The use of anabolic steroids has been prevalent in football at many levels and may have also likely contributed to the changes in weight observed over the past 70 years. The use of anabolic steroids to increase muscle mass was first reported in the early 1940s (21,42). Although college and professional football governing bodies have outlawed the use of steroids, it has been reported that many players, particularly offensive and defensive linemen, use them in an effort to increase body size and muscular strength (21).
A number of rule changes may have also contributed to the change in body weight and body composition among college and professional American football players over the past 70 years. As the game of football developed, there have changes to the rules governing the sport. In 1951, a rule was implemented that no offensive guard or tackle including the center could catch the ball on a forward pass. This limited the offensive lineman's job to just blocking and took away the skilled aspect for that position group. Additionally, in 1971, a rule against blocking below the waist was implemented. This rule change took away the use of the chop block and scramble block, both of which provided an advantage for small and quick offensive linemen. As a consequence, there was an increased demand for larger and stronger linemen. It is also possible that different types of offensive and defensive schemes have contributed to the changes in body size and composition over the past 70 years. For example, larger offensive linemen provide better pass protection for the quarterback on a team that might use a passing offense. Additionally, larger defensive linemen, because of their large size, make effectively running the football in the middle of the line more difficult to accomplish.
There are several factors that could be considered as limitations to this study. First, the mixed levels (divisions 1, 2, and 3) of college football players reported in the research literature may have masked more profound changes in the division 1 level subjects. Although no published studies have directly compared height, body weight, and body composition across college level divisions, the larger, stronger, and faster players are more commonly found in the division 1 level. Second, the evolution of the game through various playing eras could result in one type of offensive or defensive strategy prevailing at a particular time or with a particular team and therefore influencing the results for a specific time period. Finally, combining the various positions together for the analysis could also influence the changes in the dependent variables. For example, wide receivers could get taller in height and defensive backs shorter in height. In a combined group, these changes would be diluted in the data set. However, despite these limitations, we feel confident that the data presented in this article supports what is intuitively known, that college and professional football players have increased body size during the past 70 years.
Results from this study could be used in a number of general ways as athletes and programs constantly change. The reported values may be representative of the body size and composition of college and professional football athletes. This would provide a standard size for comparing changes in body height, body weight, and composition in professional and collegiate football players per position. Coaches and athletes could use the results to set obtainable goals dealing with body size and composition. This study could also be used to examine the health implications of excessive weight gains in specific position groups. As observed in the study, there has been a significant increase in weight and a change in body composition in mixed linemen. These increases are seen as necessary in professional and collegiate football players, but for the nonathletic person in America, the weight and body composition values would be viewed as having a negative effect on health. Finally, this study can be used to provide a context for how American football has evolved over the past 70 years. The game has changed significantly and the changes in body size and composition have played a huge factor in how the game is played.
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