Originally developed in East Bloc countries, plyometric exercises are used to translate the increased strength from resistance training into increased speed and power. Although plyometrics are designed for intermediate and advanced athletes, they may be able to help you improve your game.
Beginners in fitness need to go slowly to learn proper exercise technique. Improper exercise technique increases the risk of injury. Since the fitness level of each participant is unknown and there is less supervision, there is an increased risk of injury, especially if the participant has pre-existing injuries. Therefore, the risk of use in general fitness classes are too great when related to the benefits. Coaches in athletic events can gauge whether the athlete is ready for plyometrics and closely watch their technique to avoid injury.
In athletics, as well as general fitness training, there are five stages of development. The first stage is neuromuscular facilitation, also called kinesthetic awareness. This stage involves learning to control how the body moves. The second stage is developing muscular endurance, which allows a person to be able to complete the workout routine without undue fatigue. The third and fourth stages (increased muscle mass and increased strength [the ability to exert increased force]) occur at about the same time. The fifth and final stage is development of power, which is strength with speed. The fifth stage is where plyometrics is used most effectively and requires prior development of the other four athletic qualities.
Initially, resistance training, stretching, sprints and sports drills should be sufficient to improve speed and power. The rule of thumb the Soviets used for commencing lower body plyometrics was the athlete should be capable of squatting 150 percent of bodyweight. Until that time, speed can be improved significantly with strength training and sports training techniques. The athlete’s joints and muscles need to be sturdy enough to withstand the high forces generated by plyometrics. The connective tissue doesn’t increase in strength as fast as the muscles because they have less blood supply. The initial strength change produced by resistance training is via neurological adaptation; i.e., increased motor unit recruitment and muscle fiber contraction synchronicity. Soon, there is an increase in contractile proteins in the muscle fibers, also known as muscle growth. Over time the tendons, ligaments and joint capsule increase in thickness and structural integrity. Once the athlete has become strong enough, plyometric training can begin.
Plyometric training is most applicable to sports requiring speed or power as a primary requisite for victory. The sports most clearly in this category include track and field events such as high jump, long jump, pole vault, high hurdles, shot-put, discus, javelin and the hammer-throw. Other sports in this category include boxing, martial arts, ice hockey, sprint distances in running and swimming, Olympic weightlifting and football. Sports where power and speed play a less decisive role are those where strategy, endurance or raw strength are more important. These sports include, among others, basketball, baseball, badminton, wrestling, table tennis, tennis, arm wrestling, gymnastics, ski jump, downhill skiing, water skiing and surfing.
In running, jumping and many other athletic events, the athletes’ foot or hand is in contact with the ground, ball or opponent only for a fraction of a second before the next contraction occurs. The pre-stretch that occurs when running or jumping helps the next contraction be more rapid and forceful. The body has a neurological inhibition that prevents the muscles from contracting so powerfully that it damages the tendon, or the attached bone. This inhibitory mechanism is actually set too conservatively. Utilizing training methods that use the pre-stretch contraction partly reduces this inhibition, allowing a more rapid and powerful contraction than before.
There is great variability possible in plyometrics, limited only by knowledge and creativity of the coach or practitioner. Choose exercises that simulate part or all of the movements used in the sport. Choosing the safest and most effective exercises requires an intimate knowledge of movement in a given sport, and the direction force must be applied to facilitate the movement. An experienced strength and conditioning coach or trainer who doesn’t specialize in your particular sport can watch video of a sport and pick up on the main movements requiring speed and decide which specific plyometric exercises can be chosen. If an athlete has a particularly weak area of his or her game, emphasis can be placed on that movement.
Plyometrics for lower body can include: jumping, bounding, rebounding after dropping from a height (depth drops), weight-release jumps, hopping on one leg. Any of these can be performed for vertical height or vertical distance. They can also be performed in place, forward, backward or laterally. To perform weight-release jumps, hold weights in the hands and drop them as the feet leave the ground during the jump. The idea in all these methods is to rebound as rapidly as possible.
Upper body and midsection plyometrics include some of the same techniques, but primarily use medicine balls for catching and throwing in various directions with a partner, bouncing off a wall or rebounding trampoline or doing twisting movements with a medicine ball with ropes.
Volume and intensity of plyometric training must initially be low and increase over time. Within the athletes’ program, the volume of training and the intensity are inversely proportional. Bounding drills are less intense than single-leg hops, which are less intense than depth drops. The intensity of depth drops is directly proportional to the height of the jumping platform. In medicine-ball drills, intensity varies directly with the weight of the ball and the speed with which it is thrown, bounced or dropped.
The timing of plyometrics training is important in two ways. The first way is integrating the sport skill, resistance training and plyometrics programs so they are focused on the same goals. An athlete training for muscular endurance is doing light weights and high volume (total reps) and developing a fitness base. During this time, no plyometrics are performed. When the athlete is in the muscular hypertrophy mesocycle, they will be using moderately heavy weights and medium volume. Muscular hypertrophy requires enough rest to grow. Light intensity plyometrics may be used during this cycle. During the strength-training mesocycle, the athlete lifts heavy weights at a moderate speed and somewhat low volume. Low to medium intensity plyometrics may be used.
High-intensity plyometrics should be done during the time the athlete is in the power mesocycle of resistance training. During this time, the athlete is lifting explosively for sets of one to five repetitions. This is coming toward the start of the season in strength, speed and power sports.
The other aspect of timing concerns the order in which different aspects of training are performed. After a sufficient warm-up, power training is done prior to weight training, or is done on a different day. Endurance training is performed after weight training or on a different day or different time of day. Endurance training sets up the wrong kind of motor pattern for power training and strength training. Fatigue of any kind, reduces speed and coordination.
A primary example of an event that benefits from plyometrics is the long jump, which requires the athlete to use the speed from the run into the power to propel the body as far as possible vertically. This sport requires a great deal of technique as well as a high strength-to-weight ratio. Athletes who have a high percentage of fast-twitch muscle fibers, advantageous muscle insertions and can fire as many of their total muscle fibers simultaneously as possible are likely to do well in this event. The long jump consists of the approach run, the jump and the landing. The approach run is to generate the power for the jump, so training for that part of the event would be similar to the training of the 100-meter sprinters. The jump must use the speed of the run to generate maximum speed at an angle that will produce the greatest distance before returning to the ground. The landing must be done so the athlete does not fall back or land wrong and cause injury. Each part of the event must be improved to achieve maximum performance. The coach assesses the long jumpers form to determine the limiting factor in improving performance. Initially, technique practice, strength training for the primary, secondary and stabilizing muscles, and stretching for the antagonist muscles will go far toward improving performance. The midsection stabilizes the body, absorbs shock and transfers power between the lower body and the upper body. The upper body moves to maintain balance during the run and jump and helps soften the landing. Therefore, attention must be paid to train the body as a whole.
For more information about strength training for sport, see the following articles on this Web site “Resistance Training: Sport Specific” October 16, 2000; “Strength Speed and Power” October 25, 2000; “Weight Gain, Strength, Speed and Sports Performance” September 5, 2000. Sport specific routines may also be found in sections of this Web site about your sport.
Once the athlete has mastered the technique and developed sufficient and balanced strength and flexibility, plyometric techniques can be used. Since this event is very linear and straight in motion, the plyometrics can focus on forward motion and vertical height. Lateral and backward plyometric drills are not necessary. Jumping, bounding and depth drops will increase lower extremity speed and medicine ball drills can improve midsection and upper body strength.
An example in a less obvious sport is a tennis player who lacks a powerful serve. Initially, the power of the serve can be increased by practicing serves, increasing strength with barbell or cable pullovers, overhead tricep extensions and abdominal crunches, in addition to increasing the flexibility of the shoulders and waist. After the player has developed more strength and flexibility, they can proceed to plyometric medicine-ball drills such as overhead bounce pass, seated overhead passes and overhead chopping drills in the same position.
In conclusion, plyometrics is a highly effective method of developing speed and power for intermediate and advanced athletes. However, the program should be designed and taught by a competent coach or trainer. It must be integrated into the entire training program including aerobic, anaerobic, flexibility and resistance training to prevent injury and increase effectiveness.