NASM: Chapter 18 - Plyometric (Reactive) Training Concepts

Exercises that generate quick, powerful movements involving an explosive concentric muscle contraction preceded by eccentric muscle action.

Primarily revolves around exercise that uses explosive movements such as bouncing, hopping, or jumping to develop muscular power.

Ability of muscles to exert maximal force output in a minimal amount of time.

True.

To move with efficiency, forces must be dampened (eccentrically), stabilized (isometrically), and then accelerated (concentrically).
(Think of the movements/process of jumping).

• An active stretch (eccentric contraction) of a muscle followed by an immediate shortening (concentric contraction) of that same muscle

• Require neuromuscular system to react quickly and efficiently after an eccentric muscle action to produce a concentric contraction and impart necessary force (acceleration) in the appropriate direction.

(Since the length of the tendon increases due to the active stretch phase, if the series elastic component acts as a spring, it would therefore be storing more potential energy. This energy would be released as the tendon shortened. Thus, the recoil of the tendon during the shortening phase of the movement would result in a more efficient movement than one in which no energy had been stored)

Eccentric phase: deceleration, loading, yielding, counter movement, cocking phase.

• Increase muscle spindle activity by pre-stretching the muscles before activation.

• Potential energy is stored in the elastic component of the muscle during this loading phase much like stretching a rubber band.

• Also known as the transition phase

• The electromechanical delay between eccentric and concentric contraction during which that muscle must switch from overcoming force to imparting force in the intended direction (rapid switch = more powerful response)

• Involves dynamic stabilization and is the time between the end of the eccentric muscle action (the loading or deceleration phase) and the initiation of the concentric contraction (the unloading or force production phase)

• Also known as the unloading phase

• Occurs immediately after the amortization phase

• involved a concentric contraction resulting in enhanced muscular performance after the eccentric phase of muscle contraction

• Synonymous with releasing a rubber band after it was stretched

1. Enhances excitability, sensitivity, and reactivity of the neuromuscular system

2. Increases the rate of force production (power)

3. Increases motor unit recruitment

4. Increases firing frequency (rate coding)

5. Increases motor unit synchronization

Decreasing the reaction time of the muscle action spectrum (result = increase speed of movement in the individual).

1. Systematic

2. Progressive

3. Client must exhibit proper levels of total body strength, core strength, and balance before progressing into plyometric training

4. Client must wear supportive shoes and perform exercises on a proper training surface such as grass field, basketball court, or track

1. Involve little joint motion

2. Designed to establish optimal landing mechanics, postural alignment, and reactive neuromuscular efficiency (coordination during dynamic movement).

3. Hold “Landing Position” (stabilize) for 3-5 seconds (during this time, the individual should make any adjustments necessary to correct faulty postures before repeating the exercise.

1. Squat jump (with stabilization)

2. Box jump-up (with stabilization)

3. Box jump-down (with stabilization)

4. Multiplanar jump (with stabilization)

1. Involve more dynamic eccentric and concentric movement through a full range of motion

2. The specificity, speed, and neural demand may also be progressed at this level

3. Exercises tend to improve dynamic joint stabilization, eccentric strength, rate of force production, and neuromuscular efficiency of the entire HMS

4. Exercises performed in a repetitive fashion (spending relatively short time on the ground before repeating the drill)

1. Squat jump

2. Tuck jump

3. Butt kick

4. Power step-up

1. Involve the entire muscle action spectrum and contraction-velocity spectrum used during integrated, functional movements

2. Designed to further improve the rate of force production, eccentric strength, reactive strength, reactive joint stabilization, dynamic neuromuscular efficiency and optimal force production.

3. Exercises performed as fast and as explosives as possible (safely).

1. Ice Skaters (skater jumps)

2. Single-Leg Power Step-Up

3. Proprioceptively Plyometrics