PLYOMETRICS

Definition A quick, powerful movement involving pre-stretching the muscle and activating the stretch-shortening cycle to produce a subsequently stronger concentric contraction Jump training

PLYOMETRICS Purpose To heighten the excitability of the nervous system for improved reactive ability of the neuromuscular system Eg: Increased recruitment of motor neurons Eg: Increased production of power

The physiological basis for plyometric training lies in the fact that muscles have a natural tendency to rebound when stretched rapidly. Very similar to a rubber band and shooting it across the room, the greater the stretch the further it will fly

So in the muscle, an eccentric muscle action is utilized to pre load ( stretch) the muscle so that the antagonistic concentric muscle action can be enhanced, resulting in a greater jump. Simply put you can jump higher following a landing from a jump or step down, than if you jump from a standing position.

“Plyo” “metric” All ADLs and Athletic movements require use of the stretch-shortening cycles Upper Extremity and Lower Extremity plyometric training intensities are different based on muscle mass and muscle function

Training Principles Goal: to decrease the time between the eccentric muscle contraction and the initiation of the overcoming concentric contraction. Stretch-Shortening Cycle  coupling of eccentric/concentric contractions Two components of cycle A) proprioceptive reflexes B) elastic properties of muscle fibres

NM Result Plyometric training can desensitize the Golgi Tendon Organ, allowing for increased force generated by the Musculoskeletal system GTO and Muscle spindle oppose each other and a resulting greater force is produced.

PLYOMETRICS Relies more on the rate of stretch rather then the length of stretch Greatest concentric force production when immediately preceded by eccentric contraction Time, magnitude, & velocity of stretch directly affects the ability to use stored elastic energy

Program Development When starting a plyometrics program specificity is key. Sport specific movement patterns should be broken down into basic movements Basic movements can then be progressed upon as the program develops. Prerequisites are required: Strength base/ stability/ flexibility

Plyometric Program Development Training program can be manipulated for easy or difficulty through various different ways. Direction of body movement Horizontal movement < Vertical movement Weight of the Athlete Heavier the athlete = more intense Speed of execution of the Exercise Increased speed = increased demand

External Load Adding an external load =increase demand Intensity Progress from simple to complex Volume Count # of foot contacts Beginners: foot contacts per session Advanced: foot contacts per session Frequency Full recovery: hours depending on intensity

Recovery Definition-rest time between exercise sets Goal dependent  increase in muscular power or muscular endurance? Plyometrics are anaerobic, therefore require longer recovery periods

Recovery con’t Power training  work/rest ratio of 1:3 or 1:4 Endurance training  1:1 or 1:2, usually associated with circuit training intensity volume Important to listen what body is saying and to underestimate the max to prevent injury

When to use PLYOMETRICS Rehab setting-the latter part of rehab starting in the advanced strengthening phase once the athlete has obtained appropriate strength base Training setting (uninjured athlete) - plyometrics program should follow periodization concept

Guidelines for Plyometric Programming 1. Program should be specific to goals of the athlete. Sport-specific skills should be broken down and trained in their smaller components and rebuilt to a coordinated activity-specific movement. 2. Quality is more important than quantity. Intensity should be kept at a maximum. 3. The greater the intensity the greater the recovery time.

Guidelines for Plyometric Programming 4. Can have greatest benefit at end of a normal workout because it will replicate the athlete exercising under partial or total fatigue. Use low-medium stress exercises in these situations to prevent injury. 5. Stop when proper technique can no longer be maintained. 6. Work with progression increase number of exercises increase number of reps/sets decrease rest period between sets

Guidelines for Plyometric Programming 7. No more than 3x per week during preseason (focus on volume). No more than 2x per week during season (focus on intensity). 8. Dynamic testing on regular basis to provide progression and motivational feedback 9. Proper equipment (ie. Footwear, landing surface) Key is to use ankle, knee, and hip together upon landing for proper absorption of shock and transferring the force.

Integrating Plyometrics into the Rehab Program Lower extremity plyometrics are an effective functional closed-chain exercise that can be incorporated into the sports. the eccentric prestretch adds stress to the tendinous portion of the contractile unit, and therefore is beneficial for managing tendonitis. healing tendinous tissue is stressed causing an increase in ultimate tensile strength.