Unlike training for muscle gains and resistance training, training for speed must work a different set of muscles to make the athlete faster. Football speed drills should focus on working the fast twitch muscle fibers, which enhance an athlete's speed and agility, unlike slow twitch muscles, which improve an athlete's resistance strength. Regular strength training will not make a football player faster, so football speed drills must focus on building fast twitch muscles and explosive power. This means football speed drills should focus on sprinting, interval training, and plyometrics rather than simple weight training for mass.
Ladder exercises improve both speed and agility and should be a part of any set of football speed drills. Ladder drills can be combined with sprints to form a good speed building series of exercises. Focus the drills on both forward movement and lateral movement, and don't forget to include deceleration as part of your football speed drills. A football player needs to be able to stop quickly and change direction suddenly, so make sure your drills account for such a need.
Interval training is a good way to improve speed. This involves running at a moderate pace, then sprinting for a short period of time, and then returning to the moderate pace. This process should be repeated several times; the repetition of rest allows the muscles to recover adequately, and the interval of sprinting helps develop fast twitch muscles. A variety of drills focus on interval training, and intervals can be done on a bicycle as well to improve overall leg development and speed performance.
Including plyometrics in the football speed drills is a good idea for more advanced athletes. Plyometrics focus on developing explosive power, which can help a football player accelerate quickly. The exercises involve a series of jumps as well as explosive movements while handling a medicine ball or other heavy object. The jumps are often performed in conjunction with a held position. A diagonal jump, for example, is executed by jumping forward and to the left, landing on the left foot only, holding that position momentarily, then jumping forward and to the right.
As with any other type of speed or muscle development and training, football speed drills should begin and end with proper stretching. Speed drills, particularly intervals, can be stressful on the body and injury is always possible. Properly stretching the leg muscles before exercise and immediately following a workout can keep the muscles limber and prepared for intense movements. Stretch before the workout to prevent injuries, and stretch after a workout because the muscles are limber and loose at this point, and most conducive to effective stretching.