By Bret Contreras
Many strength coaches repeat the same outdated concept over and over, stating that “sprint speed is determined by the amount of force you put into the ground.” Force is a vector quantity that has magnitude and direction. It’s not just the force you put into the ground; force relative to bodymass in addition to the direction of force application help determine sprint acceleration performance.
A recent study titled, Technical Ability of Force Application as a Determinant Factor of Sprint Performance, by Morin and colleagues, took a close look at sprint performance using 12 subjects including 2 sprinters. What they found was that speed was determined by high amounts of net horizontal force, which is calculated by subtracting braking forces from propulsive forces. They measured mean vertical, horizontal, and total forces, and what was very unique about this study is that they measured the forces during each step of the acceleration, which allowed them to calculate an index of force application technique involving the net direction of force per stride.
What the researchers found was that the direction of force application and the net horizontal ground reaction forces were significantly correlated with sprint performance, but vertical ground reaction forces and total ground reaction forces were not. The researchers concluded that:
The take home message for strength coaches, track & field coaches, and sprinters is that you really need to analyze vectors and forces and determine which ranges of motion require accentuated force development. Squats, Oly lifts, ballistics and plyos are staples, but end range hip extension strength and power is maximized by combining training methods including hip thrust variations, pendulum quadruped variations, back extensions and reverse hypers, sled work, horizontal jumps, and of course, sprints.
Many strength coaches repeat the same outdated concept over and over, stating that “sprint speed is determined by the amount of force you put into the ground.” Force is a vector quantity that has magnitude and direction. It’s not just the force you put into the ground; force relative to bodymass in addition to the direction of force application help determine sprint acceleration performance.
A recent study titled, Technical Ability of Force Application as a Determinant Factor of Sprint Performance, by Morin and colleagues, took a close look at sprint performance using 12 subjects including 2 sprinters. What they found was that speed was determined by high amounts of net horizontal force, which is calculated by subtracting braking forces from propulsive forces. They measured mean vertical, horizontal, and total forces, and what was very unique about this study is that they measured the forces during each step of the acceleration, which allowed them to calculate an index of force application technique involving the net direction of force per stride.
What the researchers found was that the direction of force application and the net horizontal ground reaction forces were significantly correlated with sprint performance, but vertical ground reaction forces and total ground reaction forces were not. The researchers concluded that:
In fact, the researchers elaborated on this during the study, stating the following:
Mel Siff understood this many years ago. So did Charlie Francis when he said, “looks right, flies right” and prescribed his sprinters (including Ben Johnson) the reverse leg press; an anteroposterior hip extension exercise that focused on end-range glute strength, similar to the pendulum quadruped donkey kick.
The take home message for strength coaches, track & field coaches, and sprinters is that you really need to analyze vectors and forces and determine which ranges of motion require accentuated force development. Squats, Oly lifts, ballistics and plyos are staples, but end range hip extension strength and power is maximized by combining training methods including hip thrust variations, pendulum quadruped variations, back extensions and reverse hypers, sled work, horizontal jumps, and of course, sprints.
