Shin Angles, Shin Drop and Acceleration

The shin acts as the organic protractor with the ground to show which direction the athlete is directing force. Good shing angles distinguish mediocre accelerators from great ones. 

Shin angles are the key to moving anywhere fast from a dead start. In order to accelerate, an athlete has to produce horizontal force against the ground and the shin acts as an organic protractor with the ground to show which direction the athlete is directing force. Good shing angles distinguish mediocre accelerators from great ones. 

Strength is a large determinant of how low an athlete can push, as a weak athlete is not able to push properly if they let themselves drop too far down in position. 

Skeletal position will always determine function. In acceleration, the trajectory of the shin in relation to the ground should be between 23-40 degrees. 

If you look at the starting position of the torso and lower extremities in relation to the ground, you will see that a shin angle higher than 40 degrees will result in the pelvis pulling over the femur, creating an upright position. This will interrupt horizontal trajectory and the force vector strength of the lower limbs. 

Shin angles in acceleration in team sports are often very similar. Shin angles lower than 30 degrees or less have been shown. 

Furthermore, a poor cue given for linear acceleration is to fully dorsiflex (going beyond locked position) and plant with a completely flat foot during the acceleration portion of the sprint. This cue is harmful to linear speed, through hurting the dynamics of the Achilles tendon spring, as well as interfering with an optimal shin angle in the first two steps, since it limits how far the shin angle can drop. 

We tend to see this flat foot action in effect in many sled pushes and sled march drills, which can loosen the achilles tendon to shin torso angles that require a significant amount of stiffness there. 

Addressing Ankle Function in Shin Drops for Acceleration 

The best accelerators have a rigid ankle (in the sagittal plane). This goes hand in hand with a strong and powerful pinky toe action (lifting the pinky toe to lead the foot into pronation). This will allow a lock and slightly dorsiflexed ankle positions.