Football (American)

Football is the epitome of an anaerobic sport, with the length of plays almost never exceeding 15 seconds, followed by a rest period between each play. However, when the ball is in play, the players are giving maximal muscular effort to move, or stop the movement of, the ball. Football players also carry the extra burden of heavy equipment, which adds to the energy requirement. The fuels most used in this type of activity are phosphocreatine and muscle glycogen, making the traditional "steak and potato" pregame meal less than ideal for ensuring an optimal storage of muscle glycogen because there is a relative overemphasis of protein (steak) and a relative underemphasis of carbohydrate (potato). Football players are in need of nutrition education, particularly on the use of dietary supplements.¹⁹ A study of college football players found that supplementing with creatine monohydrate had a performance-enhancing effect by improving lifting volume and repeated sprint performance.²⁰ Another study of football players found that creatine supplementation was useful for enhancing peak force and maximal strength.²¹ However, findings from this and other studies should be reviewed carefully before embarking on a path of ergogenic-aid supplementation because the total energy intake adequacy of the subjects in this study was not evaluated. It is unclear, therefore, if the apparent benefit of creatine monohydrate supplementation would be sustained if the total energy intake of the football players was adequate. In one of the few studies assessing the safety of long-term creatine supplementation, creatine monohydrate showed no long-term detrimental effects on kidney or liver function in the absence of other supplements.²²

In another study evaluating nutrient supplementation on athletic performance, football players who consumed chromium picolinate supplements for 9 weeks experienced no improvement in either body composition or strength when compared with a group of football players who did not supplement.²³

The stop-and-go nature of football, which vacillates between bouts of maximal effort and rest during a game, is also associated with a high level of body water loss. This loss of body fluid negatively affects cooling ability, athletic performance, and concentration.²⁴ A study of the consumption of carbohydrate-containing beverages among football players showed that these beverages were better able to maintain plasma volume than water alone.²⁵ Since maintenance of plasma volume is strongly associated with athletic performance, football players should consider consuming a well-designed sports beverage to maintain endurance and performance. Adequate fluid consumption before, during, and after games and practices should be an important part of the training regimen.

Football players at every level have recently been getting bigger and stronger each year and have a relatively positive body image when compared with other male athletes.²⁶ In a survey of high school all-American football teams from 1963 to 1971 and from 1972 to 1989, significant increases were found in the ratio of weight to height (body mass index) in the 1970s and 1980s that did not exist earlier.²⁷ In other words, football players are getting heavier (relative to their heights) at a rate much higher than existed before 1963.

Increased weight by itself may not be a good thing for football players. One study found that football linemen with higher body fat percentages and higher body mass indexes had higher rates of lower-extremity injuries.²⁸ In another study, football players with higher body fat levels had a 2.5 times higher relative risk of injury than those with lower body fat levels.²⁹ In addition, an unexpectedly high rate of obesity was found among adolescent football players. Since body image is inversely related to body fat percentage in male athletes (i.e., higher body fats are associated with poor body image), it is important to help athletes understand how to increase weight properly if higher weight is desirable.³⁰ Taken together, these findings strongly suggest that increasing lean (muscle) mass rather than simply increasing weight should be a priority for football players.

Many have questioned whether the recent increases in player size are due to improved preselection in a sport that attracts larger individuals, improved nutrition, or an increased reliance on anabolic steroid hormones. It is possible, of course, for all or any combination of these factors to contribute to the recent increases seen in the body mass index. Football players appear to be eating better than their non- football-playing counterparts. In a study of junior high school and high school football players, it was found that, in general, their nutrient and energy intakes were better than those seen in the U.S. population of same-age boys.³¹ Energy intakes, which are often below recommended levels in other sports, appear to meet close to 94 percent of the requirement in the assessed football players. One nutrient found to be low in this study was zinc. In another study of football players, low zinc levels negatively affected maximal workloads. Since zinc is most easily obtained through the consumption of red meat, football players should consider a regular consumption of meat. However, meat consumption should not interfere with or replace the consumption of carbohydrates, which are essential for maintaining performance in stop-and-go activities. Vegetarians may be at higher risk for inadequate zinc intake, so they should be assessed by a qualified medical professional to determine if zinc supplements are warranted.

Weight loss is often an issue for lightweight football players. These players, who must maintain weight below a given threshold to be eligible to play, often display eating patterns that are unhealthy. In one study, 20 percent believed their weight-control practices frequently interfered with their thinking and other activities, and 42 percent had a pattern of dysfunctional eating. Almost 10 percent of those surveyed were practicing binge-rge (bulimic) eating behaviors.³²

As with athletes in other professional sports, time-zone changes make a difference in performance outcomes. It has been found, for instance, that when games are played at night, west coast teams have a clear advantage over eastern and central time-zone teams.³³ The west coast teams feel as if thet're playing earlier in the day relative to the other teams, so they do not suffer from end-of-day fatigue to the degree that other teams do. West coast teams have a 75 percent and 68 percent winning percentage when playing central and east coast teams, respectively, and still maintain a high winning percentage even when playing in away games (approximately 68 percent). These data strongly suggest that football players who travel across time zones to play should do whatever it takes to return to normal circadian rhythms. Among the positive actions that players can take are eating small amounts of foods frequently and consuming plenty of fluids during travel. Keeping this in mind, football players must consider the following nutritionally relevant factors for their sport.

Football requires a high level of strength and speed of short duration but high frequency. Football players are involved in activities that require repeated bouts of high effort interspersed with periods of rest. This type of activity requires a high level of carbohydrate to properly fuel the muscles. Therefore, football players should enter the game with their muscle glycogen levels full. However, even with muscle glycogen storage at its peak, a player cannot play an entire game without depleting muscle glycogen in specific muscle groups. Therefore, football players should take every opportunity to consume a carbohydrate-containing beverage during breaks in the game.

Linemen require a high mass. Although high mass affords linemen a clear advantage, the ability to move the mass quickly is equally important. Therefore, linemen should strive for a high level of muscle mass rather than just higher weight. To achieve this, consumption of a diet that meets the energy requirements plus 300 to 500 calories for the higher mass is needed, along with a relatively low intake of fat (less than 25 percent of total calories) and a moderate intake of protein (12 to 15 percent of total calories or about 1.5 grams of protein per kilogram of body weight). This type of diet, coupled with exercise that places stress on the muscles, helps enlarge the muscle mass. Increasing total energy intake through the consumption of a high level of fatty foods greatly enables an increase in fat storage (and therefore mass), but fat does not contribute to strength. Thus, fatty foods negatively alter the strength-toweight ratio and make it more difficult for a lineman to move quickly and powerfully off the line.

Backfield defensive positions and pass receivers require high agility, speed, and quick reaction time. High speed and agility require a relatively low level of body fat. Therefore, these football players should have an eating pattern that limits fat storage (i.e., a high-carbohydrate, low-fat intake with the consumption of small, frequent meals). Since multiple 40-yard sprints down the field to catch (or defend against) long passes will quickly deplete muscle glycogen storage, consumption of carbohydrate-containing beverages at natural breaks during the game is desirable. During hot and humid days, consuming these beverages will also enhance the ability to maintain a desirable hydration state.

Repeated high-intensity activity while carrying equipment (e.g., pads, helmet) translates into high sweat losses. The fluid in sweat must be replaced to maintain optimal performance. To do this, consumption of sports beverages that contain a 6 to 7 percent carbohydrate solution are useful for maintaining the body's water level and replenish ing carbohydrate fuel. When assessed, athletes typically place themselves in a state of voluntary underhydration, so there is every reason to set up a strategy that makes football players consciously consume fluids during every possible break in the game.