Football players, being in a sport that emphasizes strength and requires weight training, need to get enough protein to maintain and gain muscle. The long-distance runner needs maximum stores of glycogen to supply him with energy over time. Those involved in lengthy tennis matches or other aerobic activity need to make sure they attend to their nutritional needs for both fuel and cell nutrition before, during, and after their sport. Myriad supplements exist for which adequate testing and evidence is not available in definitive form. However, it is available in anecdotal form.
Creatine is an example.
In truth, it will help in strength sports and help one gain more muscle, power and mass. However, it is not a source of energy and does not meet your nutritional requirements. Dehydration and muscle pulls are a frequent product of this supplement. Fluid intake for athletes are as critical a concern as nutrition. Hydration must be a lifestyle event.