Most sports have a few things in common, one of these commonalities is that you can never be too fast. In fact being faster than your competitors correlates well with getting more scoring opportunities in games. But before going on any further let’s define what speed is, for most sports it is how fast an athlete can sprint at maximal speed.
Sprinting, is a highly technical skill that has been determined to be an outcome of stride length and stride frequency. The basic premise is that the longer your stride length, this will allow you to cover more distance and will help you be faster, and for stride frequency, the shorter time you take between each stride, the faster you will be able to sprint. Stride length is primarily determined by limb lengths and motor control and typically is optimized once the athlete begins to learn the skill that is sprinting. So while this is a determinant of speed, there is little to be done to improve it once the pattern has been set. Stride frequency is based on two factors, flight time and ground contact time, and commonly is trained by teaching athletes to quickly “turn over” and move their legs as fast as possible. While this may make sense at first glance, a deeper dive into the subject shows that flight time, no matter if it’s measured from Olympic level athletes or your average grandma remains relatively unchanged. In fact when studies on stride frequency are done, the one commonality among elite level sprinters is that they get on and off the ground the fastest which is the main factor that can be modified to improve maximal sprinting speed. So while it may be common practices to ask your athletes to swing their feet faster to be faster, this actually doesn’t determine sprint speed and instead the focus should be on shortening the ground contact times.
With emphasis being on shortening ground contact times, there are a few ways to do it. First and foremost, proper body positioning must be maintained. The pelvis should be slightly posteriorly rotated (butt tucked down) as this sets the body up for proper positioning at touch down, as well as not allowing the swing leg hip into hyperextension. By being in proper position at touch down, with the stance leg under the hips, the ground contact time is reduced because the leg effectively acts as a spring and gets up and off the ground without any extra time needed to get into position, but when an athlete reaches out in front of them, this may seem like it will increase stride length and will improve sprinting, but in reality it increases braking forces at the foot and increases the amount of time needed to get into proper position and then off the ground.
A second important training factor for improving sprint performance is to get strong. There are clear correlations of an athletes squat one rep max and their sprint time being faster up to about a strength level of 2x body weight. Another reason this is important is because during sprinting, forces of up to 5x body weight are experienced at every ground contact, and that’s only on one leg, so increasing the amount of force you can put into the ground in a very short period of time is essential to sprinting faster. Strength training also increases the stiffness of your tendons, the ability to withstand deformation, which is essential to being able to withstand the forces associated with sprinting.
Ultimately while sprinting is a highly technical skill, the major determinant of success and running really really fast is how quickly you can get off the ground. Making sure that you are in proper position at touch down, getting strong are some of the best ways to aid the effort of getting fast, instead of spending time trying to move your legs faster or increase your stride length which may ultimately lead to decreases in performance.