Principles of Plyometric Training

Article By: Ken Grace Chabot College

Plyometric training can act as the bridge between strength, power, speed and skill. Plyometric training utilizes the stretch reflex mechanism in the muscle to improve the reaction time of the nervous system in that muscle. The goal of plyometric training is to develop the power and speed that is specific to a sport.

Plyometrics work by quickly stretching the muscle (eccentric) followed by a very quick muscle contraction (concentric). The quick eccentric phase activates and fires the muscle spindle, located in the muscle fiber, and a tremendous amount of force is generated through elastic energy that is stored in the tendons and muscle.

Each time a specific and correct plyometric action is practiced the nerve synapse and the muscle it innervates, becomes better at transmitting the same signal in the future. These synapses over time can increase the receptor sites for greater excitation of the muscle. Simply put the body learns to create to a faster and greater muscle contraction.

The key to plyometric exercise is to keep the amortization phase (the landing and pre-stretch phase) as short as possible. This phase is significant. If the loading phase is too long the Golgi Tendon Organ will take over and cancel out the function of the Muscle Spindle. The shorter the amortization phase, the greater the muscle spindle action and elastic response from the muscle and the nervous system. The amortization phase should be between .003 to .005 seconds. The athlete must always react as if the ground is hot like a frying pan. As soon as ground contact time increases, or fatigue is noticed, it is time to stop the exercise.

Guidelines to Follow:

1. Plyometric Exercises should be performed at 100% effort. Plyometric training is an Alactic Energy System exercise.

2. Each set should last no longer then 6 to 8 seconds.

3. Full recovery should occur between sets.

4. Plyometric exercises should be progressive in intensity. Start with easy exercises and develop in intensity and complexity.

5. The skill and speed of performing a plyometric exercise is of great importance. Stop before fatigue breaks down technique.

Intensity Rating & Type of Exercise

Intensity of Exercise

Number of Reps and Sets

Rest Interval Between Sets

5 - Rope Skipping, Hops on Spot, Light Implements, Throws

Low

10 to 30 reps

10 to 15 sets

2 to 3 minutes

4 - Simple Bounding, Medicine Ball, Low Short Hops, Two Leg jumps, Hops and Steps

Moderate

10 to 25 reps

10 to 20 sets

3 to 5 minutes

3- Two Leg Jumps from height, Upper Body, Medicine Ball for Distance, Shot Throws, Low Drop Reaction and Rebound, 2 leg and 1 leg bounding

Sub-Maximal

3 to 25 reps

5 to 15 sets

3 to 5 minutes

2 - Medicine Ball Shocks, Drop Jumps

Very High

5 to 15 reps

5 to 15 sets

5 to 7 minutes

1 - High Reactive Jumps, Shock hits, Heavy Implements, In Depth Jumps

Maximal

3 to 5 reps

10 to 20 sets

8 to 10 minutes

Progress and development through the five degrees of intensity is a long-term proposition. The incorporation of low impact exercises into the training program for young athletes, for 2 to 4 years, represents the time needed for the progressive adaptation of the ligaments, tendons and bones of the body (Bompa).