Foot Strike in Top Speed Sprint Mechanics Vertical or Horizontal Force: Understanding the Dynamics of the Push

Research has shown time and time again that vertical force and stiffness are key KPI’s in creating fast athletes at top speed. The palpable question becomes, how much of each do we truly need? 

Horizontal Push in Top Speed 

Horizontal Force in top speed is important to understand since many strength coaches look at the vertical force contribution in sprinting and immediately point to squats and deadlifts which is not always the case. There are plenty of strong, compressed athletes who have poor vertical force application & placement needed for sprinting. 

Many times, pure strength training teaches athletes to disregard the foot complex by extending through the hip and utilizing the heels as a reference point. 

You often hear the term “knees out, spread the floor, push through the heels.” 

Research Regarding Horizontal Thrust 

J/B Morin has stated in numerous studies, “If too much strength is developed in the hip musculature and posterior chain and not the ankle/foot complex - the ability to transmit high levels of force will be non-existent.” 

Think of a car with a big motor but flat tires. Getting the motor more and more powerful may do more harm than good for true display of athleticism. In sprinting, when reaching top speed horizontal force has a high level of significance. 

Horizontal forces must INCREASE more than vertical forces as athletes approach maximal speed. “Effects of Running Velocity on Running Kinematics and Kinetics.” Brughelli, Matt et all. Journal of Strength and Conditioning. 

The Solution 

An equal blend of front side and backside lift as the stance leg connects with the ground, and rolls from supination to pronation, the knee and ankle are not completely rigid. The heel touches slightly to allow the shin to become a lever and horizontal forces will still be applied in the process of meeting the speed of the running surface. 

Vertical versus horizontal forces in top speed, vertical force won’t be the limiting factor - horizontal force will be. “Belli, et al. Moment and Power of Lower Limb Joints in Running, International Journal of Sports Medicine.”

Horizontal force production in maximal speed running is the result of the knee behind the hip with fulcrum push enhanced by it’s flexion. The optimal range is around 150 degrees from the torso to the hip and back side push. 

Moreover, attacking from above tends to coincide with a powerful hip drive and stiff ankle contact, resulting in efficient elastic recoil with minimal strain on the hamstrings. Keeping the force application elastic at higher speeds helps spread the stress across more connective tissue, incorporating better use of the tendons and fascia with less localized trauma to the posterior chain. When performed properly, athletes look like they are bouncing down the runway rather than forcing their way.

Frame by Frame Analysis 

Over the last year I’ve been working hard to display both components of the sprint. We have data for over 300 athletes with video analysis to help validate our claims. Furthermore, we use a blend of both Joel Smith’s, Barr’s and Altis Kinogram for Top Speed Mechanics. Where it truly connects is experiencing it for yourself and having the data to back it up.