Sprinting Mechanics Made Simple: Max Velocity

In our first blog talking about sprinting mechanics we discussed acceleration. We used the acronym PAL (Posture, Arm Action, and Leg Action) to simplify the coaching components of acceleration. In this article we will do the same, but addressing Max Velocity. Max Velocity can be defined as the highest attainable velocity an object can reach, which is demonstrated by discontinuation of acceleration. Most athletes will reach Max Velocity between 20-50 m. While there are similarities between Acceleration and Max Velocity mechanics there are also some important differences to make note of.    

Posture

If you remember, posture allows us to appropriately orient force in the direction needed, which is typically either horizontal or vertical depending on what phase of sprinting you’re in. Other benefits include increased force production and minimized braking forces. In Max Velocity Sprinting the majority of forces going into the ground are vertical to help maintain forward propulsion. With this in mind, your posture during Max Velocity Sprinting should be upright or perpendicular to the ground with the head, neck, and shoulders stacked on top of the hips. Anything more than a slight forward lean will cause over-rotation, alter the direction of force production negatively and decrease speed potential.

Arm Action

The arms in sprinting are used as a counter-balance to help manage rotational forces generated from aggressive leg action. This allows athletes to keep force production going straight ahead. The arms also help to synchronize efficient leg action for better force production. In regard to mechanics, during a Max Velocity Sprint, the front side hand should block slightly above shoulder height with the elbow at approximately a 75-degree angle. From this position, the athlete strikes down and back with the hand as the arm swings behind the body. The elbow will re-bend to approximately 105 degrees allowing for some daylight between the rear arm and the torso. In other words, on the front side you will have an acute elbow angle and on the backside you will have an obtuse elbow angle.

Leg Action

Leg action at Max Velocity should be cyclical in nature with minimal backside leg swing. Too much backside leg swing can cause an athlete to overreach. This is characterized by the athlete striking too far out in front of their center of mass. Ideally we would like the foot contact to occur either under or slightly in front of the center of mass. Finally the ankle should be dorsiflexed which will allow athletes to efficiently store energy so they can have quick and violent ground contacts with each step. In the stance phase an athlete should look like they’re making a ‘Figure 4’ with their legs (refer to image 1 full-support).  

The PAL coaching paradigm is a great strategy for developing the fundamentals of proper sprinting mechanics, and is an easy way to explain complex movements to athletes. Improving sprinting mechanics will help athletes:

·   Synchronize explosive upper/lower body movement

·   Optimize directional forces that support efficient acceleration

·   Reduce energy leaks and wasted energy

·   Reduce the likelihood of soft-tissue injuries      

·   Maximize current speed potential through appropriate muscular length-tension relationships

If applied appropriately and in conjunction with a well-rounded speed, power and strength program this simple frame-work can drastically improve an athlete's sprinting ability!

Erik Jernstrom

Director of Sports Performance @ EForce

Weyand, P.G., Sternlight, D.B., Bellizzi, M.J., & Wright, S. (2000). Faster top running speeds are achieved with greater ground forces not more rapid leg movements. Journal of Applied Physiology 89: 1991-1999.

Seagrave, L., Mouchbahani, R., O’Donnell, K. (2009). Neuro-Biomechanics of Maximum Velocity Sprinting. IAAF NSA.

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