Chapter 19 Program Design and Technique for Plyometric Training

Plyometric exercises

Activities that enable a muscle to reach maximal force in the shortest possible time

• Quick, powerful movement using a pre-stretch or countermovement that involves the stretch-shortening cycle

Ballistic exercises minimally include contributions from…

From the neuromuscular component of the SSC

Rebound exercises require what type of contributions?

Physio-mechanical SSC contributions

When properly implemented, plyometric training consistently improves what?

Improves an athlete’s ability to produce muscle force and power

Impulse

The integral of force over time

• Directly influences an athletes performance by changing momentum

What does an increased impulse do?

Leads to greater momentum, allowing athletes to accelerate and decelerate more effectively

How are plyometrics explained

Explained through mechanical and physiological models

SEC - Series Elastic Component

When stretched stores elastic energy that increases force production

CC - Contractile Component

Actin, Myosin, and Cross bridges. Primary source of muscle force during concentric muscle action

PEC - Parallel Elastic Component

Exerts a passive force with unstimulated muscle stretch

• Epimysium, Perimysium, Endomysium, and Sarcolemma

Mechanical Model of Plyometrics

In the mechanical model, elastic energy in the musculotendinous components is increase with a rapid stretch and then stored

What happens when movement is immediately followed by a concentric muscle action?

The stored elastic energy is released, increasing the total force production

What is the workhorse of plyometric exercise?

The Series Elastic Component (SEC) is the workhorse

What constitutes the majority of the SEC?

Tendons

Neurophysiological Model of Plyometrics

Involves the potentiation of the concentric muscle action by use of the stretch reflex

• This reflexive component of plyometric exercise is primarily composed of muscle spindle activity

What are two elastic structures that can be stretched within the muscle during plyometric exercises?

The Series Elastic Component (SEC) and Parallel Elastic Component (PEC)

This contains collagenous structures, which provide stability and protection to the musculature

The Parallel Elastic Component

Stretch-Shortening Cycle

Employs the energy storage capabilities of the SEC and stimulation of the stretch reflex to facilitate a maximal increase in muscle recruitment over a minimal amount of time.

What are the three phases of the stretch-shortening cycle?

Eccentric, Amortization, Concentric

Amortization is crucial because…

Most crucial phase in allowing greater power production

• Must be kept short or energy will be lost as heat

Eccentric (I)

Stretch of the agonist muscle

• Elastic energy is stored in the series elastic component. Muscle spindles are stimulated

Amortization (II)

Pause between phases I and III

• Type 1A afferent nerves synapse with alpha motor neurons

• Alpha motor neurons transmit signals to agonist muscle group

Concentric (III)

Shortening of agonist muscle fibers

• Elastic energy is released from the series elastic component (SEC)

• Alpha motor neurons stimulate the agonist muscle group

What does a high stretch rate result in?

Results in greater muscle recruitment and activity during the SSC concentric phase

Flat foot landing technique

resulted in significantly longer ground contact times in comparison to active forefoot landings

What does the stretch-shortening cycle serve as

Serves as a protective function within the myotendinous structures of the musculoskeletal system

What must be incorporated in the design of a plyometric training program?

Mode, intensity, frequency, duration, volume, density, technique development and progression, and a warm-up period

What must a trainer analyze to support the needs of their athlete?

Evaluate their sport, sport position, anthropometry, and training status

Heavier athletes face exponentially higher loads in…

Gravity-assisted exercises than athletes with a lower mass

What are lower body plyometrics appropriate for?

Appropriate for any athlete and any sport or rehabilitation context

• provides an ideal and highly variable training stimulus that positively transfers training benefits to a variety of sports

What does the plyometric session design include

Includes the sagittal plane, as well as hops, bounds, jumps, depth jumps, and depth hops

Hops

Takeoff from one foot and land on the same foot. Volume is measured by distance traveled or number of foot contacts

• develops acceleration and deceleration capabilities in a single limb, with intensity defined by displacement velocity and volume defined by foot contacts

Bounds

Taekoff from one foot and landing or transitioning through to the other foot

• can be singular (ballistic bound) or reactive (multiple repetitive actions with alternating ground contact)

Jumps

Takeoff and landing with two feet that may be horizontal or vertical in nature

• Height/length of a jump determines the intensity of the action

• Volume determined by number of foot contacts

Depth jumps and depth hops

Use gravity and the athlete’s weight to increase exercise intensity

• Height of the box determines the intensity of the action and the volume by the number of foot contacts

Upper body actions need to be link with?

Linked with impulses generated through segmental actions initiated in the lower body if they are to be effective in the transfer to performance

Upper body plyometrics includes…

Throws, slams, pulls, pushes

• rapid powerful upper body movements

Throws

Single or both arms projecting a medicine ball or other external eight horizontally or vertically

• progressions include increased mass, target distance, or change of complexity (kneeling vs standing)

Slams

Double arm movement forcefully bringing a medicine ball directly down to the ground

• Progressions include increased mass, increased targte velocity

Pull

Ballistically pulling the body in a vertical direction (explosive supine row or pull up)

Push

Pressing the body away from the ground in a prone position

• Progressions: drop to ground contact, decreasing flight time to increase movement velocity, or increasing complexity through lateral/overhead movements

Lower body anchored

Suspended in prone position or sit-up position with feet anchored so that upper body is free to move

• Progression by incorporating or increasing an external resistance or movement velocity

Upper body anchored

Lying supine, holding a fixed object or a partner’s legs, while the lower body is free to move

• Progression by incorporating or increasing external resistance, movement velocity or plane of motion (Increased transverse plane involvement is more complex than sagittal plane only)

Plyometric intensity

refers to the stress placed on muscles, connective tissues, and joints during an exercise (impact)

Intensity of the drill and the ground contact time can increase when?

When changing directions

Factors that affect intensity

Points of contact, speed, technique, strength, directional change, vertical components, and the athlete’s mass