Acceleration Phase
The technical model during the acceleration phase of the sprint, including the start, should have the following characteristics:
1. Acceleration is achieved by driving or pushing with the drive leg. This requires
a good forward lean-from the ground up, not the waist. Remember that the amount of lean an athlete exhibits will be directly
proportional to acceleration. Also remember that acceleration does not mean speed but the rate of increasing speed. If a line
is drawn from the foot of the drive leg through the center of mass, that line also should extend through the shoulder joint
and head. That line should be at approximately a 45-degree angle from the ground.
2.
The free leg will drive low and fast to place the foot down under the body and may even fall behind the center of mass depending
on how quickly the athlete accelerates. Without proper acceleration the athletes will stumble since they are leaning so far
forward.
3. The heel recovery of the drive leg will be very low coming out of the
blocks in order to get the foot down fast in order to drive again and overcome inertia.
4.
With each succeeding drive step, the athletes' speed grows until they reach their top speed. As speed increases acceleration
decreases, so you should observe a continuous lessening of body lean. Upon reaching top speed, posture should be very erect.
5. Along with the stride-by-stride decrease in acceleration, you should observe the
athletes' heels rise higher as they get into their normal sprint stride.
6. The
arm action during the acceleration phase is similar to the sprint striding phase. However, in the early phases of the start
the hands will be driven very high and forward relative to the athlete's torso. The arms play a very important role in maintaining
balance, rhythm, and relaxation, so you should have the athlete consciously work them vigorously.
7. As the athlete moves from the acceleration phase into the normal stride, he/she will want to focus upon
the technical model for the sprint striding phase.
