Sports that require some form of running also show the need for acceleration. It is part and parcel of every run regardless of whether it is in track or in a team or individual sport. In many cases it is a key to success in the particular sport as for example, hockey, lacrosse, soccer, football, basketball and in some cases baseball.
The greater the ability of the athlete to accelerate, the more successful you can be. This is especially true in team sports in which you typically run about 5 to 10 yards before doing something else. It usually determines who gets to the ball first. And the one who gets there first is usually more successful in executing a particular task.
In discussing the key actions that occur in acceleration it is first necessary to distinguish the acceleration that takes place when the athlete is already in a run or when he is first starting in a standing or crouch position or when coming out of the blocks. The joint actions at the start from the blocks are different from those in the standing start.
In this article I will discuss mainly the acceleration that occurs from a standing position or during a sub-maximal speed run. In the standing start,, the most distinctive characteristic of the player who can quickly accelerate is a quick first step. It has two key components; an explosive knee drive and a powerful leg push-off.
After the first step, most important is to have maximum turnover speed (stride frequency) together with an increasing stride length. The faster the knee is driven forward and then back and down, the sooner the leg can make contact with the ground to generate more force to propel you forward. The faster this occurs, the quicker you can take the next step and the more you can accelerate.
In the first few steps, you must rely on powerful knee and ankle joint extension to propel you forward. This is done together with a forward lean of the body to keep your weight in front of the body (to keep the body center of gravity slightly forward). This enables you to get your legs under the body faster to keep you in dynamic balance and to move more quickly.
The more you lean forward, the faster the legs must get under the body. This ensures that you have quick turnover so that you move forward very quickly and with good form. In tennis, soccer, football, basketball, baseball and lacrosse, 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, usually about 20-30°.
For maximum quickness, it is necessary to get into a slight forward lean position before beginning to accelerate. In other words, you must lean forward (shift your weight forward) and begin to lose your balance as you push-off and step out. This is the key to a quick start! It is necessary to think lean, and then drive.
Ankle extension is especially important in acceleration while running. 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. Also the leg extension will direct your body upwards rather than forward which is the key to greater acceleration.
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 prevent you from sinking too low, which then requires you to raise the body. Doing this over an extended distance is uneconomical and can lead to early fatigue.
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 more it propels your upper body forward and the faster you can take the next step to increase your speed.
You should think of literally grabbing the ground surface with the foot in a pawing action to propel the upper body forward. As a result, each acceleration stride should be slightly longer than the previous one until you attain a basic upright position, at which time you resume your regular running stride.
The more upright you become, the more important is the pulling of the swing leg down and back (known as pawback) to ensure greater quickness and power in each stride. In sports such as tennis, football and soccer, field hockey, team handball and lacrosse, you usually accelerate for 5-10 yards. This is usually the distance you must run to get to the ball or to execute a particular action or to change direction again.
For more information, see Build a Better Athlete and Explosive Running.