Acceleration Adjustments


“Speed kills” is a quote often used by performance coaches, but acceleration is the mass murderer of sport. Some athletes are naturally better accelerators and some seem to be missing that ability, regardless of their performance in the weight room. Mechanically things look sufficient but what is going on? One of the members from Australia shared some of the ground contact times with the classic Coh study from Slovenia. If they were more progressive, they would have taken advantage of their location and have done a TMG profile of the athletes on the lower body groups to get stiffness, relaxation rates, and other muscle parameters. I would have loved to see wireless EMG at 1 gig frequency as well as a pressure profile of the foot strike at 700 hz. Why? We need more anatomical performance information on the duration of the foot strike to see ways to improve performance with training. The information by Coh is fantastic, but we need some root information on what causes the better and lesser step durations.

The new metrics of ground contact time are based on the constraints, what you can change and what you can’t change. Some changes are more easily done but some are nearly loss causes. The following 10 metrics are what I am going to experiment with this month with the Microgate The following 10 metrics are what I am going to experiment with this month with the Microgate technology from Optosource.

Step Length- The distance between opposing feet in the forward position

Step Width- The distance between feet in early foot contacts horizontally

Step Placement- The amount of external rotation of the foot.

Contact Time- The amount of time the foot is on the ground in ms.

Center of Pressure- The path of pressure through the foot and ankle joint system.

Lower limb Activity- The contractile timeline of muscles that help with pretension.

Joint Radial Motion- How much degrees of movement of the ankle and tibial angle of foot strike to the ground

Positive Foot Velocity- The speed from transition of maximal hip flexion to foot contact

Pelvic Position- The angle of both tilt and inclination of the body

Torso Lean- The angle from pelvis to mid torso (head can be factored in but it usually encourages a false sense of lean).

Is this all necessary? For a research paper yes but believe it or not interventions such as training adjustments to get lower limb stiffness, orthotic intervention, arm action change, and general cuing can help. With such time constraints each practice must be successful since we can’t sprint every day. We can’t do much trial and error anymore if we want drug free progress in sprinting. If coaches collaborate we will start getting better ways to improve 0-20m times with technical and training methods that are practical.

Carl Valle

Carl Valle

Track & Field Coach
Carl is an expert coach who has produced champions in swimming, track and numerous other sports. He is one of the foremost experts in the fields of nutrition and restoration.
Carl Valle

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