Plyometrics
Plyometrics, also called jump training, is a training technique designed to increase muscular power and explosiveness. Originally developed for Olympic athletes, plyometric training has become a popular workout for people of all ages, including children and adolescents. Plyometric training conditions the body with dynamic resistance exercises that rapidly stretch a muscle (eccentric phase) and then rapidly shorten it (concentric phase). Hopping and jumping exercises, for example, subject the quadriceps to a stretch - shortening cycle that strengthens the muscle, increases vertical jump, and reduces the force of impact on the joints. Because plyometric exercises mimic the motions used in sports such as skiing, tennis, football, basketball, volleyball, and boxing, plyometric training often is used to condition professional and amateur adult athletes. But children and adolescents also can benefit from a properly designed and supervised plyometric routine.
Benefits
Plyometric training is associated with many benefits. First popularized in the 1970s by state sport trainers in East Germany, it’s based on scientific evidence showing that the stretch - shortening cycle prompts the stretch or myotactic reflex of muscle and improves the power of muscular contraction. Plyometric training can lead to improvements in the following:
• Vertical jump performance
• Muscle strength
• Joint protection
In addition, regular participation in a plyometric training program may help participants control their body weight. When plyometric training is combined with active warm-ups, stretching exercises, and other weight training, evidence suggests that it may significantly improve an athlete’s explosive power. Because plyometric training strengthens muscles and decreases impact forces on the joints, it may reduce the risk of injury, especially in younger female basketball and soccer players who have a risk of anterior cruciate ligament (ACL) injury that’s two to eight times higher than that of their male counterparts. ACL injury-prevention programs, such as plyometrics, are designed to enhance the proper nerve and muscle control of the knee.
Considerations
Plyometric training is associated with some risks, including an increased risk of injury, especially in participants who don’t have adequate strength to begin with. If you’re considering plyometrics, it’s important to first consult with a sports medicine doctor or therapist who can assess your suitability for a plyometric training program. Then you should select a qualified coach or trainer who can gradually introduce you to more difficult exercises. If you’re in poor physical condition or have bone or joint problems, you’re probably not a good candidate for plyometrics.
Even if you’re a seasoned athlete, it’s important to remember that any training routine that builds strength through explosive movement has an increased risk of injury. In the sport science community, reported injuries associated with plyometrics programs of depth jumping have stirred considerable debate over the safety of the technique. Any high-impact activity increases the risk of injury to lower-body joints such as the knee and ankle.
Plyometric training is usually safe and effective. Make sure you’ve received adequate screening from a sports medicine doctor or therapist and enrolled in a program led by a qualified instructor who matches the exercises to your age and fitness level and teaches proper landing techniques before gradually advancing to more difficult exercises. Beginners should only train under proper supervision, and they should start with easy, safe ground-level jump-offs onto padded surfaces such as grass or a gym mat.
The most effective plyometric programs emphasize the quality instead of the quantity of jumps, and they teach safe landing techniques such as landing from toe to heel from a vertical jump, using the entire foot as a rocker to distribute the impact over a greater surface area, and avoiding excessive side-to-side motion at the knee. To promote low-impact landings, some instructors encourage participants to visualize themselves landing as light as a feather. More complicated exercises such as depth jumping should only be introduced over time, and instructors need to assess participants’ physical condition and injury status before advancing them to the next level. If necessary, a program can be modified over time to optimize gains and prevent overtraining. Other safety considerations include the use of foam or other soft barriers and boxes and jumping surfaces that can’t twist on impact. Participants should rest for at least 48 hours between training sessions.
A thorough warm-up is essential for plyometric training. Attention should be given to jogging, stretching, striding, and general mobility about the joints involved in the planned plyometric session. A cool-down should follow each session. It is wise not to perform too many repetitions in any one session, and because it is a quality session, emphasizing speed rather than endurance, split the work into sets with ample recovery in between. An experienced athlete conducting lower-body plyometrics may make 150 to 200 contacts in a session, while athletes new to plyometric work should start with low- to medium-intensity exercise with around 40 contacts per session (e.g., 2 sets of 6 bunny hops is 12 contacts). A similar approach should be taken with upper-body plyometrics, such as the medicine ball exercises described earlier. Allow at least 1 minute of rest between each set so as to allow the neuromuscular system to recover, and allow 3 days between plyometric sessions.
For bounding exercises, use surfaces such as grass or resilient surfaces. Avoid cement floors because there is no cushioning. Choose well-cushioned shoes that are stable and can absorb some of the impact. All athletes should undergo general orthopedic screening before engaging in plyometric training. Particular attention should be given to structural or postural problems that may predispose the athlete to injury.
