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Plyometrics: The Bridge Between Strength & Power


By Lorne Goldenberg BPE, CSCS, PFLC
From the Journal of Hockey Conditioning & Player Development

Plyometrics is a term that describes exercises that help bridge the gap between strength and speed. In the early 1970’s these exercises were simply called jump training. By the late 70’s jump training was termed plyometrics by American track coach Fred Wilt. In Latin terms this means ‘measurable increases’. This type of training was made famous by Eastern European athletes, who were continually beating North American athletes at most strength and speed events. Through the late 70’s and 80’s plyometrics has become an integral part of any sports conditioning program.

Plyometrics helps bridge the gap between strength and speed by enhancing neuromuscular physiology. This is demonstrated by improved power. In all true plyometric movements, there is eccentric loading and stretch placed on the muscle. A perfect example would be a hockey player racing for a puck to prevent an icing call. As he touches the puck he begins his stop so he does not crash into the boards. This stopping movement will initiate the eccentric load on the player’s quadriceps. To stay in play the player immediately pushes-off to skate back into position. This push-off is the concentric contraction. This resulting concentric contraction is much more powerful, compared to if the player just pushed-off from a dead stop. This muscle response occurs with no conscious thought on the player’s part. Without this response, the player’s knee would buckle and he would collapse. The above response is a result of the muscle spindles, also known as intrafusal fibres, which lie parallel to the myofibrils of the muscle. When the player initiates the stopping movement on the ice, the muscle spindle senses the stretch and load on the muscle. It then receives a message from the brain to initiate a stretch reflex (myotatic reflex). The result is push-off or concentric contraction. This stretch reflex works in the same manner as the knee jerk you would experience when tapped with a rubber hammer.

"When a player strength trains his muscles generally get strong,
not necessarily more quick and powerful"

When a player strength trains his muscles generally get strong, not necessarily more quick and powerful. Plyometric exercise helps to bridge the gap between strength and speed by developing the stretch reflex, which in turn will help in developing a more powerful muscle.

Part ll of this article will describe the more practical elements of a plyometrics program, including some exercise demonstrations.


By Lorne Goldenberg BPE, CSCS, PFLC

From the Journal of Hockey Conditioning & Player Development

Part one of this article dealt with the scientific foundations for performing plyometric exercises. Part 2 will deal with exercise guidelines and safe execution of plyometric exercises.

As with any type of exercise warm up and stretching is very important. Aerobic type activity (i.e. running, cycling etc.) should be performed for 6-8 minutes at a low intensity. This should be followed by 10-15 minutes of slow and active stretching.

"When performing the jumps, execution is very important"

When performing the jumps, execution is very important. If they are not done with maximum effort and speed, the training effect will not be optimal. The other point to consider is how often and how many sets and reps? Plyometrics should not be done any more than twice per week. It is a high intensity type of exercise and more than twice per week may lead to potential overuse injuries. Sets and reps are variables that many people seem to be confused about. Generally with most plyometric exercises 2-5 sets of 6-10 jumps per set are sufficient. I have seen many people use sets of 30-60 seconds per exercise. This is too long and will cause fatigue when performing the jumps, which will lead to you doing them slowly. This type of exercise must done without fatigue, otherwise you will be teaching yourself to be slow.

The last point to think about when performing your jumps is that you should attempt to keep your heel off the ground when landing. If you land flat footed you will dampen the stretch reflex in your muscle (this was discussed in the previous issue). In the early stages you may land flat footed, but as you become more proficient at your jumps attempt to keep the heel from hitting the ground.

By combining a plyometric and strength training program you will be on your way to developing fast, explosive legs. This will in turn transfer to very positive results on the ice.


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