Rotational and Linear Aspects of Sprinting

Although there are definitely linear aspects to sprinting—i.e., the athlete is trying to travel a straight line up the track from point A to point B—and side sway running actions are inefficient, it is important to understand that running features rotational actions that counterbalance one another. Dan Pfaff explains in this video how the hips and shoulders coordinate in this way. How the athletes perceive the rotation is an important part of their ability to continue to effectively apply force and elevate appropriately as the feet spend less and less time on the ground.

After seeing how fast Ben Johnson's start and initial acceleration was at about the 12 second mark of this video, go to the 3 minute and 46 second mark and watch for about a minute for a great example of how power is generated via internal and external pelvic rotation. FYI - In my "Three-Point and Four-Point Start" blog I'll address the movement prior to the gun that Ben was allowed to do (illegal in my opinion).

A major theme of this website is that I feel that this and other aspects are maximized through good positioning, coordination, and effective movement during the starting steps as the athlete heads up the track. It is also important to understand that the time the feet spend on the ground gets less and less as the acceleration continues, and the task is to still be able to deliver significant forces to the ground although the strides come through really fast, and the feet are on the ground for only brief moments.

Torque

Rotation is related to torque, and as I explained in my "First Three Steps" blog, gravity is an important element that is related to torque as the athlete is brought down to the ground for each stride. A bottom line in my mind is that this is part of what an athlete utilizes to move through space efficiently and effectively, and if not channeled effectively, this rotation can help lead to the athlete to stumble or even fall on his/her face early in the race, or the athlete can choose to over-react by standing up when he/she should be effectively driving. Torque represents a valuable component of the generation and utilization of momentum.

An aspect that helps to successfully deal with rotation early on in the race is that the feet spend a longer time on the ground during the start and initial acceleration, but as velocity increases and the feet spend less and less time on the ground, there isn't the time to successfully deal with this rotation if the athlete chooses to continue hanging forward. That is why after 15 meters or so, velocity should already be so high, that the athlete should avoid inappropriately leaning forward, because of the little time to compensate for this rotation.

Very Important Aspect of Rotation and Appropriate Force Application

During upright sprinting the "build-up of pretension" in the hamstrings during the scissoring action of the legs facilitates an effective rotation described in this lengthy quote from the book Running. "During the scissor-like motion of the legs during the floating phase, developing forces tilt the pelvis backward and forward: the hamstrings and abdominal muscles tilt the pelvis backward, while the iliopsoas on the swing leg side tilts it forward. As the swing leg oscillates outward, the hamstrings together with the abdominal muscles exert a force that tilts the pelvis backward. The iliopsoas can slow this backward tilt somewhat, thus causing pre-stretch in the hamstrings of the front leg. In this way, the pelvis works like a lever so that energy can be transferred from the trailing to the leading leg."

During upright sprinting, the rotation described above can help facilitate a variation in the posture of the trunk from being very slightly forward to very slightly backward. This movement is not to be exaggerated. Examples of these movements being done effectively can be seen in this video.

Final Word

Most of any race is spent in an upright position. Skillful management of the various rotational and linear aspects during the start and initial acceleration makes it easier to do so when upright. As has been said in my other blogs, each phase of the sprint should flow into the one that follows, with a primary aspect being achieving body positions that lead to maximal performance. This is demonstrated in this very brief Tellez video.

As it pertains to rotation, a lot of coaches mistakenly feel that all rotational movements are signs of inefficiency, thinking that they create side to side movement down the track. The movements of the hips and shoulders are to counterbalance each other as Dan Pfaff explained in his video I included in the first paragraph above, and once again, despite all the technical aspects coaches can consider presenting their athletes with, the objective is for the athlete to simply accomplish moving effectively and efficiently up the track. Various reflexes, reactions to actions, etc..., also contribute to successful movement up the track, so coaches need to understand the value of allowing the athlete to gain experience to discover what works well for him/her within certain fundamental parameters.