We ask training guru Steve Jack about the rudiments of achieving explosive plyometric power, and the effort needed to achieve absolute success in this technique.
Plyometrics, used primarily for athletic conditioning, was first devised in the 1920s by track and field athletes, becoming popular in the eastern block during the 1950s and 1960s. However, back then it was termed ‘jump training’. It wasn’t until the American track coach Fred Wilt coined the term ‘plyometric’ in 1975 that the term would come into modern usage amongst western athletes. Plyometric comes from the Latin root words ‘plio’ (i.e. more) and ‘metric’ (i.e. to measure), thus it is easy to see how the word was born out of athletic conditioning and why most of its early applications were designed for elite track and field athletes. The popularity soon spread to wrestlers and boxers as the eastern block countries led the way with conditioning their athletes in this vein.
Before beginning a plyometric regime it is important to understand the physiological implications that conditioning in this way has on the body. It is also important to understand it as an everyday activity that is performed by everyone, no matter their age or physical condition. A plyometric movement is one where a stretch of the muscle occurs prior to the explosive contraction that follows. This is commonly called ‘loading’: the faster and greater the load, the bigger the following contraction. It is as simple as that. Whether it be a father playing throw and catch with his son, or a mother chasing a stray toddler, or an elderly person walking down a step, plyometric events are involved in some degree. Now if we take this to the other end of the spectrum and look at plyometrics from a martial arts point of view, the principle of load and unload remains the same as Mum and Dad, except that with the martial arts, we increase the load.
Why plyometrics work with regard to improving movement potential is down to four key physiological potentials inherent in the human body. The first is that tendons have a property called elastin. Elastin has the potential to store energy (the common analogy here is the rubber band) and does so during loading (muscle lengthening), this stored energy can then be transferred to the force output during the following concentric contraction (shortening), generating greater power.
The second is the stretch reflex of the human body. Think of the knee tap test at the doctor, the stretch reflex is a protective mechanism in the human body which prevents a muscle from being violently over stretched by the involuntary contraction of the over stretched muscles. Thus if someone jumps in the air and immediately jumps again this will activate the stretch reflex by creating an involuntary contraction of the over stretched muscles resulting in a greater force of output.
The third factor to consider is the length tension and interaction of the muscles. It has been demonstrated that the optimal length tension for a muscle to generate force is slightly greater than resting. A plyometric movement will stretch a muscle to a greater degree than its resting state to put it in a position where it is in its ideal length to generate force. This is easily verified by conducting a stiff legged standing jump versus a preloaded jump.
The final and often overlooked physiological potential in the human body is the potential to override our Golgi tendon organs. The Golgi tendon organs, located in the muscle, act as a force production inhibitor. This is a safety mechanism that prevents the body from injuring itself by producing too great a contraction that may cause the tendon to come away from the bone. The Golgi tendon organ’s set point (before they activate) is generally set above the actual force necessary to create damage. This set point is shifted higher during resistance and plyometric training, thus improving the potential for explosive movements. It is like driving the car with the handbrake on and then gradually taking it off over time, steadily improving the power output available. You know this is true because when you started training your pain threshold for resistance work was a lot higher. This is why your debut students think you are killing them when they first start training!
Now how do we take this and apply it to conditioning ourselves or our athletes? We need to remember the function formula: the more your plyometric exercise looks and feels like the actual activity you want to improve, the more effective it will be for the athlete. If you throw punches you will want to load (lengthen) in the same way that you throw a punch then explode. You can add additional load by adding an external resistance such as a bungee. The same can apply to throwing: by adding different weighted punch bags, you can simulate a highly loaded plyometric throw and all the tweaks and adjustments that may occur on the mat.
- Steve Jack
|
Fitness and Nutrition 
(0 vote)
