Introduction to Plyometrics
When talking about plyometrics most coaches think of box jumps; this is only part of the picture. Plyometrics are a form of exercise designed to produce the greatest strength gains in as short a time as possible. Plyometrics utilize the forces of gravity to store potential energy in the muscles, then quickly turn this stored energy into kinetic energy. The in-depth jump (box jump) is the best known example; as the athlete steps off the box and lands, legs coiled (potential energy is stored), then quickly leaps to the next box (kinetic energy is utilized). The natural elastic properties of the muscle serve as excellent store houses for the energy. To gain the maximum benefits of plyometrics it is important to note that the stored energy must be immediately used in an opposite direction.
The athletes that will benefit from plyometrics are those that require speed-strength. Speed-strength is the ability to exert maximal forces during high speed movements. Football is the classic example of a speed-strength sport but, almost any sport requires some speed-strength movements. Due to this all sports will benefit from plyometric training. The experienced coach will know what movements in each sport will benefit from plyometric training and should institute exercises to develop the speed-strength components of that sport.
To reduce the risk of injury and facilitate the strength gains that plyometrics can give, the athlete must first establish a speed and resistance training base. Beginning plyometircs too early in the conditioning cycle, or with the inexperienced athlete, can be disastrous. Several criterion need to be met before instituting a plyometric training program. These criterion are:
Physical Maturity of the Athlete
The age of the athlete or the number of years that they have participated does not measure their physical maturity. The National Strength and Conditioning Association (NSCA) recommends that the strength level for the hips and legs be based on the ability to squat 1.5 to 2.5 the athlete's body weight. This should be considered the minimum standard for shock - and htgh-intensity plyometrics. The upper body levels, according to the NSCA, should be based on the ability to do five continuous clap push-ups. Larger athletes (weight > 250 lbs) should be able to bench press their body weight, while smaller athletes (<165 lbs) should be able to bench press 1.5 times their weight, and athletes of intermediate body weight (165 to 250 lbs) should use gradiation of these guidelines.
Coachability refers to the athlete being able to respond in a positive fashion to instructions and criticism. If not, plyometric training should be delayed to prevent injury, overtraining, or undertraining. If the athlete will not respond to coaching direction they oftentimes will not perform the movements properly. This can result in poor training results or injury.
Demands of the Sport
The demands of the sport must be considered when designing the plyometric program. Determine if the sport movements are mostly linear, vertical, lateral, or a combination of these movements. For example, volleyball players require vertical and lateral movement, while long jumpers emphasize horizontal movement. The intensity and volume should also be considered in the program design. During a training phase a shot-putter may use low volume and high intensity while the 400 meter hurdler may use moderate volume and intensity.
The strength and condtioning level of the athlete must be considered prior to performing plyometrics. If the athlete does not possess sufficient muscular strength or sufficient fitness levels, injury or overtraining may result.
Several factors should be considered when the decision has been made to begin plyometric training. These should include the sport specific exercises desired, proper footwear, surface types, proper equipment needs, and training area. Other areas of consideration are the frequency, volume, intensity, progression, recovery, and the direction of motion recommendations for the exercises.
Safety includes many areas, including proper footwear, resilient surface, proper equipment, and training area size. Footwear should provide sufficient ankle and arch support to prevent injury. Running shoes should be avoided due to their narrow sole and poor upper support; crosstraining shoes are the best for plyometrics.
To prevent injuries, the landing surface should possess good shock-absorbing properties. The best surface is a grass field. A good alternative would be wrestling mats. Wood, tile, concrete, and carpet should be avoided due to their poor shock-absorbing properties. The boxes used for jumps should ber sturdy, have a nonslip top, and have rounded edges. The size of the training area depends on the type of exercises being used. Long-response drills may require a straightaway of 100 meters. Bounding drills require at least 30 meters of straightaway. For box jumps, adequate ceiling height must be provided.
Frequency, volume, intensity, progression, and recovery all refer to the training session itself. Frequency is the number of workouts per week. Volume is the number of foot contacts per workout. Intensity refers to the amount of stress placed on the muscle during the workout. Progression is the change from low-intensity to medium-intensity to high-intensity levels as the athlete progresses. Recovery is the rest that is allowed between the individual sets of the drills. The linked articles will explore these aspects of the plyometric workout.
©2000 - 2009 David Edell
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Last Update for AthleticAdvisor.com: 10/24/2009 12:09:35 AM