Once you understand how the body functions as a kinetic chain then the next step is to train movements not muscles. The basic movements are rotating, bending, extending, pushing, reaching, and pulling. Why is this so important? Neurologically the brain does not recognize individual muscles; rather it recognizes patterns of movement in response to sensory input. The muscles are slaves of the brain. Isolation of specific muscles does not appropriately emphasize dynamic, multi-dimensional development of patterns. Traditionally we have been taught the opposite. We learn individual muscles, but it is through movement that the muscles integrate and work together to produce and reduce force. Traditionally we study muscles in the anatomical position, but movement does not occur in the anatomical position. Movement occurs in reaction to gravity, ground reaction forces, and momentum. The Central Nervous System is the command station that controls and directs all movement. The CNS calls for preprogrammed patterns of movement that can be modified in countless ways to react appropriately to gravity, ground reaction forces, and momentum. Each activity is subjected to further refinements and adjustments by feedback from the body’s proprioceptors. This process ensures optimal neuromuscular control and efficiency of function. What are the mechanical implications of this in training? In strength training this tells us to use multiple joint movements rather than isolated movements.
The gait cycle is the basis for all human motion. The fundamental assumption is that we are bipedal terrestrial beings. Virtually everything we do in sport is reciprocal, that is the limbs working in opposition. Gait is characterized by a stance phase and swing phase in walking and a stance and flight phase in running. Muscle activity and the timing of muscle firing are predictable as gait progresses from walking to sprinting. The biomechanical implications of this are far reaching. It will impact the selection of drills, strength training exercises, plyometric exercises and rehab techniques. Understanding the gait cycle and its global implication for movement have greatly influenced the postures and positions that I use for various exercises. For example based on recruitment and function most of the core training I do now is done standing and moving in order to engage the muscles of the core in the diagonal rotational patterns as they function in movement relative to gravity.
There has been much talk about movement as open or closed chain. This is somewhat of an artificial distinction when one looks closely at movement, especially the gait cycle. Movement is the timing of opening and closing the chain. In running the swing leg (leg not on the ground) results in transfer of momentum to the supporting leg. This occurs as one body segment decelerates the next segment in the chain begins to accelerate as momentum is transferred from one segment to the other. Another example is the force that properly directed arm action can impart through other body segments to the ground in sprinting.
Biomechanics can really help to make a clear distinction between similar movements and same movements in the search for the highest degree of specificity in training. Remember that the highest degree of specificity is the actual event or movement. Unfortunately that does not afford the ability to overload in order to improve. Therefore as coaches we look for derivatives or parts of the movement or the event in order to train the actual movement or event to be better. To make this process more exact we need to thoroughly understand the biomechanics of the actual movement. It is common to see pitchers and quarterbacks throwing from their knees with the stated goal to improve “arm strength.” From a biomechanical perspective this may be counterproductive. Throwing involves the whole kinetic chain therefore taking large segments out of the action like the legs will interfere with timing and could put more strain on the arm and shoulder than the actual act of throwing. Another example is alternate leg bounding to improve speed. The goal of this drill is to decease contact time, in actual fact alternate leg bounding results in contact time two times greater than what occurs in actual sprinting. It looks like the movements that occur in running but it is similar not the same. Another example is the use of underweight and overweight balls for the pitcher. We found through biomechanical analysis that there was very little difference throwing an underweight or an overweight ball as long as they were not too heavy or too light. Therefore this is a viable training activity that is biomechanically the same for the pitcher. Use knowledge of biomechanics of movement to design drills and exercise that will give maximum return for the time invested. The training time will be more effective because it will have more direct transfer and time will be better utilized.
If you look at a relatively simple movement like distance running from a biomechanical perspective it can be quite revealing. The average distance runner takes approximately 1,000 to 1,500-foot strikes per mile. Each leg bears the weight of the entire body, as both feet never touch the ground at the same time in running. The force of landing is approximately three times body weight in .3 to .4 tenths of a second depending on speed of the run. That means a 150 pound runner is placing 450 pounds of force on each leg, every stride. What can you do with this information? How can this be used to define or modify a training program or rehab an injured runner? Very simply most distance coaches hold strength training for the legs in distain. The fact is that strengthening the legs has the potential to increase stride length and help absorb the shock of landing. Therefore from a biomechanical perspective distance runners should do specific leg strength work.
It is not necessary to be a biomechaist to think biomechanically. There are a few principles of movement that explain how all sport skills are done. Learn and apply those principles to improve your coaching
