The Secret of the Stretch Shortening Cycle

Plyometrics; the key to enhancing your ability to improving your performance capacity. Plyometrics or sometimes referred to as reversible muscle action are movements in which a muscle group is stretched and immediately contracted. An example of a plyometric would be depth drop where an individual steps off a box or step and upon landing immediately jumps into the air. These types of movements train the muscular and nervous systems by enhancing the ability of tissues to deform (stretch) much like a rubber band. While this stretch or deformation is occurring energy is stored, if this deformation is directly followed by movement some of the stored energy is applied to the movement allowing the individual performing the movement to apply more force into the vector desired. Plyometrics are able to increase the deformation by inhibiting the reflex from the Golgi tendon organ which acts as a safety mechanism and causes the muscle to decrease force production. They also enhance the ability of force application by increasing intermuscular and intramuscular coordination which in turn increases excitation of agonists and synergists and inhibition of antagonists, increased motor unit recruitment, firing rates and synchronization.

                Now that we know WHAT plyometrics are and what they do let’s look at practical ways to implement them into a training program. To effectively design and implement plyometrics you must implement them with care and caution. Plyometrics utilize extremely high loads on the joints and tissues of the body. The key factors for applying successful Plyometrics are vector or direction, rate of force production, and muscles performing work. Let’s dissect these concepts, a basketball player performs lateral, vertical and horizontal dynamic (vector or direction). Basketball is a game of rapid footwork and change of direction which requires a large amount of force be applied into the ground very quickly (rate of force production) and it utilizes core (shoulders-hips) and lower extremity muscles to produce these movements (muscles performing work). Now to develop a proper plyometric program for a basketball player it would be appropriate to perform Plyometrics vertically, horizontally and laterally with low ground contact time and without the aid of a machine to create a link between our lower appendages and upper.

        

      Plyometric variations are only limited by the imagination of the creator. They can utilize single leg, double leg, and alternate leg variations. Weights and heights can also be added to increase the intensity of a plyometric. A single leg step from a box into a jump is much more intense than a counter movement jump. As long as the plyometric used is specific to the demands of the event being trained for it will be effective. Imagine a marathon runner (yes runners need adequate power output to be optimally efficient transitioning from leg to leg) performing lateral Plyometrics to help them transfer forces horizontally, not very effective use of Plyometrics and will have limited carry over.

                In summary Plyometrics are a great way to increase your ability to generate power but need to be carefully planned and programmed for safety and effectiveness. Make sure that your Plyometrics are specific to what you’re trying to accomplish directionally, utilize a similar rate of force production and the same muscles required for the activity being trained for. If you follow these few steps you will be well on your way to successfully improving your performance capability.