When someone thinks of speed they think of how fast the athlete can run. However, a very important part of speed is acceleration which is related to increasing speed from a standstill. It is sometimes more important than the actual speed at the athlete attains.
For example, in running 100 m it takes approximately 1/3 the distance to accelerate to top speed which must then be maintained to the end of the distance. In many sports the athlete does not run 100 m at one time but instead runs anywhere from 5 to 30 m. This is pure acceleration, not speed.
By improving acceleration you can greatly improve how quickly the athlete gets up to top speed and how quickly he can cover short distances. This ability is often more critical than speed in most sports. It is usually the determining factor on how successfully the athlete performs.
The most distinctive characteristic of an athlete who can quickly accelerate is the first step which is very quick. It has two key components; an explosive knee (thigh) drive and a powerful ankle push-off, executed sequentially and simultaneously. After the first step, most important is maximum turnover speed (stride frequency) together with an increasing stride length especially when running more than 10-20 m.
The faster the knee is driven forward and then back and down, the sooner the leg can make contact with the ground and the faster you can take the next step. In the first few steps, you must rely on powerful knee and ankle joint extension to propel you forward.
In addition you should have a forward lean of the body to keep your weight in front of your body. The forward lean keeps the center of gravity in front of your body so that you quickly get your legs under the body to keep you in balance. The more you lean forward, the faster the legs must get under the body. As a result, you must have quick turnover to keep you in dynamic balance but yet moving forward very quickly.
In sprinting, runners start in an “all-fours” position and have great forward lean when getting started. However, in tennis, soccer, football, basketball, baseball and other sports, you must remain upright to be able to see what is happening on the field or court. Because of this, when you accelerate, the trunk lean is not excessive.
For maximum quickness, it is necessary to get the hips or entire body into a forward lean position before beginning to accelerate. In other words, you must lean forward and begin to lose your balance as you push-off and step out. This is the key to a quick start.
Ankle extension is especially important in acceleration. The main reason for this is that it takes too long for the knee to fully extend to drive the body forward except in the first step. The main role of the knee joint muscles is to hold your body up during the support phase while the knee drive and ankle extension propel the body forward.
In other words, the role of the knee joint extensor muscles is to keep your hips on a level as you accelerate. It is also necessary to drive the swing leg down and back as quickly as possible to make contact with the ground after it has reached its forward most position in the knee drive. The sooner the foot hits the ground moving backward, the sooner it propels your upper body forward and the faster you can take the next step to increase your speed.
Many players, when taking the first step, instead of pushing with the rear ankle joint and stepping forward with the front leg, actually take a small step to the rear with the rear leg and then push forward. Taking a step backward is a wasted step and takes more time to execute. This gives you a slower start.
To help ensure that you get a quick first step, both feet should be fairly close together or in a very slight stride position when you are getting ready to start. Keep in mind that in the basic ready position, your weight is equally distributed on the feet so that you can move out in any direction. However, when the direction is known, having your feet closer together and in a stride position is most effective. In this case, you push off the rear leg and step forward with the front leg.
Always think in terms of stepping out on the first step. Do not push with the rear leg and only take a short step with the forward leg. The first step should be relatively long. In general, the more the distance you can cover on the first step (up to an optimal amount), the faster you will cover the distance needed to get to your target. This quality can be trained.
If you start with a wide stride position, it becomes increasingly difficult to step out and it takes longer to bring the rear leg forward before you can push with the forward leg and step out again. This is one of the reasons why both feet should be fairly close to one another. Think of both feet as being on the starting line when you push with one and step with the other.
For more information on acceleration see Build a Better Athlete and Explosive Running.