At “Planting (touch down)” phase, the foot strikes the ground. At this point the skilled sprinter attempts to prevent a breaking action and exerts efforts to restore the horizontal velocity of the moving body’s mass. This results in better execution of the foot recovery preceding the planting action. The folded leg rotates forward and maintains flexion until the toes pass the supporting leg’s knee, so that the rotary inertia of the forward moving lower leg will slow toward zero velocity. The better sprinters plant the foot in front of the body’s projected center of mass by about 24-26 cm, while having the knee slightly flexed and stabilized.

This action, during the following rotation of the supporting leg over the ground, gives the body more distance to travel horizontally. This makes a runner more capable to better utilize the mechanical advantage of efforts applied over the longer distance, thus increasing the stride length and the sprinting speed. To benefit from this action, the sprinter has to strengthen the gluteal muscles, hamstrings, (knee flexors and hip extensors) and quadriceps muscles (knee extensor region).

The “Amortization (shock absorption)” phase starts from the moment when the foot contacts the ground and ends when the movement of the body’s center of mass downward is stopped. Excentric strength plays a magor role at this striding phase. 

The “Get-away (take off)” is the last moment of ground contact when the body’s center of mass has gained the maximum possible horizontal velocity.

Finally, the “Flying (airborne)” phase occurs when vertical and horizontal velocity project a flight curve for the athlete’s center of mass.