Equilibrium

Principles of equilibrium are most likely the most significant of all involved in the analysis of sport techniques. Equilibrium is often seen as being synonymous with such terminology as poise, position, stance and balance. Most body movements or positions that are accomplished in sport or skill related tasks involve some of the principles of equilibrium. For example, when you sit down in a chair or stand up from a sitting position, you apply some of the principles of equilibrium. The movement of walking is simply making adjustments to interrupted falling, which employs the upsetting and regaining of balance.
Equilibrium is defined as the state of rest of the body. If you are engaged in an activity that requires a high degree of immobility, then a strong position that will provide a high degree of stability must be accomplished. Wrestlers in college competing from the down position have to place themselves in a position where they would be difficult to move. On the other hand, if a low degree of equilibrium is desired, a stance or position that would allow one to easily upset his/her stability will assumed. For example, the swimmer has to position oneself in a starting position that would be easy to start from but stable enough to allow no movement prior to the start.
These examples represent elements in sport whereby the degree of equilibrium is very stable or unstable. In most activities, a position is desired that permits the participant to start quickly in any direction while at the same time protecting one from being dislodged. The state of equilibrium is somewhere between the two extremes. The stance of the racquetball player waiting for a return, or the baseball player set to field a ground ball, or the tennis player waiting for the serve are all examples which the player is well poised yet simultaneously ready to move with precision in any direction. It is this ability to move from a state of equilibrium to a desired place efficiently that separates the great athletes from the others.
As far back as the 1950's, researchers found that the most ideal positioning for athletes included stances where the feet were placed shoulder width apart, not staggered, the weight equally distributed on each foot, and the weight on each foot equally distributed between the ball of the foot and the heel; additionally, the knees should be flexed to an angle between 90 and 120 degrees between the calf and thigh (Slater-Hammil, 1953). The degree of flexion was noted to be directly proportional to the strength of the upper leg muscles. The stronger the upper leg muscles, the deeper the flexed leg position to 90 degrees.
Research as this was particularly important since it shows that athletes do not carry their weight on the balls of their feet, but distribute their weight equally throughout the plantar surface of the feet and stand ready for movement with their heels touching the floor. In other words, the expression "keep on your toes" does not necessitate a literal interpretation. Rather, it means to be alert and open to a state of readiness for moving. To this day, biomechanical research has not substantiated a more effective stance or state of readiness.
The foregoing unit is intended to introduce the concepts and techniques related to the principles of equilibrium. Optimal results in sports or recreation may be obtained from utilizing such principles. As with any analysis of movement, one must first understand the significance of the principles and purposes of the techniques to be used. In education, we term this as the "objectives." Lastly, we must be able to make application or association to the principles in the most proper way to achieve the most beneficial or desired results. This line of thinking can be assumed with any principle of movement.
Center of gravity (CoG) of the body or that point at which the weight of the body is centered, is always involved when considering equilibrium. In order to achieve the most efficient results in sports or recreational play, careful attention to the position of the CoG of the body is a significant factor in the stance and technique. For example, in order for a runner to achieve the highest rate of speed from a stationary position in a minimum amount of time, one must take a starting position that will permit the body to be forced out of equilibrium quickly. Then, one has to continue in an unstable state so as not to retard but assist in the effort to increase speed as rapidly as possible. The principles of equilibrium are shown and demonstrated in detail in the links that follow.