S B Coaches College - Force Absorption - Force Production Continuum




		Force Absorption - Force Production Continuum *Robb Rogers, M.Ed., CSCS*

All athletes and coaches are interested in force production. How high, how far and how fast are critical to success in sport. In sport, the ability to run faster and demonstrate burst in and out of changes in direction contributes greatly to the ability to create and close space. However, with total focus on force production we often lose sight of two critical elements in training and preparation that can impact performers and performances to a much greater degree than the ability to jump high, run fast and leap far. Many catastrophic injuries occur during practice and performance due to a loss of stability and/or proprioception in a joint or group of levers in the system when the strength or force absorption level of the athlete is overcome. The torque and rotation through the joint system is too much for the athlete to control and/or the load at that particular joint angle is too great at that quick impulse moment of loading.

FORCE PRODUCTION

STABILITY/PROPIOCEPTION

FORCE REDUCTION

In training and preparation of athletes it is imperative to improve the ability to absorb force. The ability to absorb force is highly correlated to the ability to produce force. In addition, it is critical to enhancing the ability to prevent injury. Stopping strength or the ability to absorb force as in landing in a jump or loading in preparation for change of direction is paramount to remaining injury free. Also, the ability to absorb that force in a short amount of time (or impulse) is important in being elastic and loading the tendon for increase power output. If the athlete does not possess the strength to absorb the force in a short impulse time then they may have to flex deeper into the movement, thus increasing the risk of poor compensation patterns and injury.

Proprioception is balance for lack of a better word. The balance through a movement, the balance through a lever system and the balance through a joint are keys to not only executing skills, landings and change of direction cleanly but also to remaining injury free. Porprioception is enhanced by training on or in an environment that challenges your balance. Leg exercises on a soft surface, with your shoe off or with your eyes closed. Core drills on a physioball, balance training on a vibration platform and any upper body loading in which the joints are weight bearing such as crawling are all methods of developing joint stability and muscular proprioception.

Developing strength and power in the body in order to jump higher, run faster and leap farther involves enhancing the ability of the athlete to load the tendons and utilize the kinetic energy stored in those tendons in order to explode off the ground. A short impulse time of force transfer into the ground for height, distance and speed is critical to high level performance. Impulse power for take offs is enhanced by either unloading the athlete by having them jump while holding a rubber band attached to a piece of equipment, downhill sprints or assisted sprinting by towing them slightly faster than they are able to sprint. During these drills, coach the athlete to focus on putting force in the ground faster as the ground contact time decreases with the increased speed of sprinting and jumping. The key to impulse loading is ensuring the athlete contacts the ground with the toe up or dorsi-flexed as they load the leg during jumping and sprinting. If the toe is down on contact the impulse time increases and the muscles are loaded and the movement is slower and less powerful.

During any type of jump, once in the air the athlete must land and landing requires stopping strength. Stopping strength is developed by loading the joint, lever system or body and moving in similar ranges of motion as the skill required in the demands of the sport or by holding in a variety of levels or joint angles for time with lesser loads. Impulse for landing is trained by asking the athlete to focus on absorbing the force in increasing shorter ranges of motion. Eventually impulse loading and jumping are stressed within one drill with the addition of either single response or repetitive depth jump box jumps. Teaching landing first and continuing to emphasize it as a part of the training regime is important as long as the athlete is training for competition.