speed

Foot speed (stride length x stride frequency) is the measure of how fast an athlete can sprint. Simply put, the more steps a runner takes at an optimal length, the more force he or she puts into the ground, the faster his or her body will move in the desired direction. It's a law of physics, Newton's third law, which states "for every action, there is an equal and opposite reaction." Quick-moving feet on the ground create more quick-moving feet in the air, which propel more quick-moving feet on the ground.
Many people believe this quickness is what separates good from great athletes. We know from research that speed is a skill that can be developed. Each of us is born with a speed potential, but we will never come close to maximizing it without the proper training. The requirements of speed within a given sport have to be analyzed so that we can train for it effectively. Specifically, while pure speed and speed development are the most important things for track sprinting athletes, agility has greater importantance for most court and field athletes. This difference has to be understood and addressed. Does an athlete have to maintain speed for a certain distance, or do they have to make a cut, change direction and avoid or respond to opponents? This crucial ability to maneuver cannot be done at top speed. Acceleration to top speed by even the world's best sprinters is not achieved until they've run about 50 yards. Other athletes need to accelerate and change direction faster and with more precision.