Behind the seemingly light and relaxed movement there is a different running technique separating him from his rivals. In my understanding, the most important factor is that Bolt uses gravity , to be more exact, gravitational torque , as the leading factor that allows him to more effectively involve all other forces, working as a whole and highly effective system for horizontal repositioning of the athlete with high velocity.
Simply speaking, in his running he uses rotation of the body around the point of support under the action of gravitational torque, which in essence is a free falling of the body forward. Certainly it is happening in a limited frame of space and time during the period of support from the vertical position to the end of support.
In reality, indeed, it is about a relatively small angle in space where the falling is happening. By our theoretical calculations these angles range from 0 to The key running Pose , favorable for performing falling forward and allowing us to integrate all participating forces into one system moving a runner forward, is the Running Pose at midstance or vertical position, when GCM general center of mass is over the point of support.
On frames 1, 10 and 19, with a varying degree of approximation, Bolt is in the running Pose, starting from the vertical and maintains it to the end of support, which can be seen on frames 3 and 11, and also between 19 and 20, where this moment is missing. Preservation of the Pose during the rotation of the body around the point of support proves that the body is rotating moving as a whole system.
On the one hand, it allows for better conservation of momentum of the body and, on the other, it allows for the use of gravitational torque for angular acceleration of the body after it passes the vertical position. Indirectly, another proof of the body rotation on support is provided by the knee of the support leg maintained in bent position. On frames , , it could be seen very well. His total leg length, relative to his total body height, is long, as is his femur, which acts as a lever to create huge strides.
Combined with a high strength-to-body weight ratio he is able to propel his legs faster. All humans have both fast and slow-twitch muscle fibres — slow twitch are more efficient at continuous, extended contractions over time, fast twitch help sprinters generate a lot of force quickly. The mix cannot be altered but training can increase the size of fast-twitch muscles.
Fast-twitch muscle fibres are therefore required for rapid movements including sprinting. Most muscles in the body tend to have a mixture of both types of muscle fibre.
This composition gives an edge enabling remarkable power and force and a speed Less force put into the ground means less pop back into the air. Laurence Ryan, a physicist in the SMU lab, calls that period "30 milliseconds to glory.
In other words, Weyand said, "You win your medal or you're out of the running based on that short duration. Sprinters like Bolt land just behind the ball of the foot, which strikes the ground at an angle of about 6 degrees. His lower leg decelerates abruptly, absorbing 16 Gs of force.
His heel drops for only 0. The total time spent on the ground with each stride is about 0. The SMU researchers did not know that one of Bolt's legs was longer than the other when they began their study six months ago. On average, Bolt struck the ground with pounds of peak force on his right leg and pounds on his left leg.
Because his right leg is shorter, it has a slightly longer drop to the track, contributing to a higher velocity for that step. A natural adaptation for Bolt has been to keep his left leg on the ground for slightly more time with each step — 0.
This gives him slightly more time to generate force with the left leg, Weyand said, providing greater lift off the ground.
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