Zone 1: The Start

ZONE 1 - The Start (Initial Stance)

The start of a 40 yard dash is important because the athlete has to overcome the effects of gravity placed upon the body and accelerate out of a static, non-moving position. It is important to understand that the goal of the start is not to necessarily win the start but rather, the athlete needs to place his body in the most efficient position to begin accelerating. Unlike Olympic events, there is no starting gun and no reaction time component. The clock starts upon the initial movement of the athlete. 


More so than any of the other three zones, the athlete's effectiveness in this zone is highly determined by their strength level and body dimensions. It is the most influenced by absolute strength or the overall explosive power the runner possesses. Tremendous contractile strength is necessary to generate the high forces to overcome inertia and for pushing against the ground in the first four to six strides where the ground contact times are generally larger. The front leg has a greater influence on this initial starting velocity because it exerts force longer and must produce the optimal impulse. The rear leg produces the greater initial force as it is the driving leg. 


So what does the start look like...

If you look at the picture on the left, you can see a few things happening. The athlete has an optimal stride rate-to-length ratio.  After the first two strides off the line, the foot touches down in front of the center of gravity.  Initially, the forward body lean is very high.  The lean decreases with increasing stride rate and length. Normal sprinting position is achieved between 14 - 18 yards for the average football combine participant. 


In the fourth frame of the picture on the left and in the picture on the right, you can see that the athlete achieves what is called "triple extension". This means that the runner's ankle, knee, and hip joints are all completely extended - helping the athlete achieve the greatest amount of force production. 


The best way to analyze correct sprinting mechanics is by dividing the human body into 3 segments. These would be Torso Posture, Arm Action, and Leg Action.


TORSO POSTURE
Torso posture is the dynamic alignment of the body. In order to sprint efficiently, the torso must maintain a proper posture through all phases of the 40 yard dash. The starting angle is approximately 42 - 45 degrees from horizontal. The head is in a relaxed position with the eyes focusing either straight ahead or on the ground. The main consideration of the initial stance is the relationship of the positioning of the hip relative to the torso. There is an acute angle with the hips well in front of the feet and the shoulder well in front of the hips. This is the "Triple Extension" position. Posture probably undergoes the most change of any of the 3 segments because the angle changes with each step as the feet start to come under the hips and the body gradually changes to an almost complete upright position in maximum velocity.


ARM ACTION
I like to use the "pistons of a car" analogy with my athletes when addressing arm action in the start position. The arms have a dynamic propulsive effect on the body. Mechanically, if the arm drives forward with the movement originating from the shoulders, the contralateral leg naturally drives forward. The most simple way to get faster is to increase one's arm action. The arms are the pistons and if they fire rapidly, the legs or the engine, will follow suit.


The athlete starts the 40 yard dash in what is called a '3 point stance'. This means that their body has 3 contact points with the ground - the right foot, left foot, and one hand. Generally, people who are right handed start with their left foot forward and right hand as the contact point with the ground. The opposite arm is raised behind the midline of the body and drives forward. The same is true vice versa for left handed runners. 

There are two components to arm action: direction and amplitude. The arms should swing from the shoulders, not the elbow. The 'karate chop' movement from the elbows does not create the proper force for the opposite leg drive. The primary movement of the arms should be down and back. The focus should be driving the elbows backward with as much force as possible. The forward action of the arms is the natural elastic response from the stretch of the muscles of the pecs and anterior deltoid resulting from the drive backward. 


The angle at the elbow is a debated topic and I tend to lean more towards the track expertise of Chuck DeBus. Most coaches teach that the angle is about 43 degrees in front of the body and extends to about 110 degrees behind the body. Chuck's position is based on the simple physics of the greater force that can be created with a longer lever arm. If the angle is increased from 43 to slightly over 90 degrees, the lever arm can create a greater amount of force. It can also drive forward more without creating a vertical force that would pull the body upwards instead of forwards. So, I would argue that the angle at the elbow changes from about 100 degrees in front of the body to an open, wide angle that is about 110 - 120 degrees on the backstroke. The hand should never swing above the chin because that tends to lessen the horizontal force and increase the vertical force of the body.


In the start and acceleration zone, the arms provide a propulsive force transferring momentum to increase ground reaction forces. In maximum speed, the arms serve as more of a balancing mechanism. 


LEG ACTION
The leg action is the final component. In order to drive forward and overcome inertia, the front shin should form an acute angle in respect to the ground. This is called a positive shin angle and is essential to understanding force application during acceleration and optimizing the stride at maximum speed. The shin angle is a means of describing the relationship of the center of gravity to the ground contact point. The front leg should form a 90 degree angle, which allows the correct usage of the large muscles of the glutes extending powerfully and pushing back against the ground. A negative shin angle results in a reaching action in which the foot hits the ground in front of the shin and thus driving the body more upward than forward. This pulling action is a weak position for force application. 

The back foot is placed approximately 6 - 12 inches behind the front foot. Most athletes place their foot way too far back. This does not load the glute properly and results in the back leg taking too much time to drive forward. The body needs to feel like it is almost falling forward when in the start position.


The most overlooked component of the start is the application of the stretch-shortening cycle. For example, when performing a vertical jump, the legs go through 3 stages. The body is lowered and the muscles are lengthened, the 'eccentric phase'. When the body starts to transition and reverse directions, there is a brief period where the muscles are neither lengthened nor shortened. This isometric muscle state is called the amortization period. The muscle is then rapidly shortened to jump upward, the 'concentric phase'. The stretch-shortening cycle refers to a natural part of most movements. When the sequence of eccentric to concentric actions is performed quickly, the muscle is stretched slightly before the concentric action. The slight stretching stores elastic energy. The addition of the elastic energy to the already existing concentric action results in a greater force. SSC actions exploit the stretch reflex as well as the intrinsic elastic qualities of the muscle-tendon complex. Elastic energy is the energy stored in tendons, other connective tissues, and the myosin cross-bridges - the majority being in the connective tissues.


The best analogy for the function of the stretch-shortening cycle is thinking of the muscle like a rubber band or a spring. If you stretch out a spring and keep it in this state for too long, it won't recoil with as much force. Same goes with a rubber band.

Finally, the legs need to take advantage of Ground Reactive Forces. Newton's 3rd Law of Motion states, "Whenever a first body exerts a force F on a second body, the second body exerts a force -F on the first body. F and -F are equal in magnitude and opposite in direction." This means that if the legs push forcefully into the ground, the ground will forcefully push back with an equal force. So if the athlete can get stronger and more powerful, he will be able to take advantage of using the ground as an object to generate more force. Having the front leg at a 90 degree angle and the back leg at approximately 100 - 130 degrees puts the body in the optimal position to derive force from the ground or Ground Reactive Forces.


The dynamic combination of the torso posture, arm actions, and leg actions results in a very fast, efficient start. It is important to realize that there is no cookie-cutter way to teach starts. Every athlete has a different genetic makeup. Height, weight, and other factors have to be taken into consideration when working with your athlete. A taller athlete has a harder time accelerating because all of his lever systems are longer, which require more time to move properly. Some athletes' nervous systems are more excitable and the initial impulse production is easier to train. Every athlete is a different blank canvas and it is the performance trainer's job to be visionary to the steps necessary to complete his final masterpiece.