Although plyometric training is not likely to result in injury, unsound, unsupervised programs could potentially result in shin splints and knee, ankle and lower back problems. These types of injuries are often a result of too many workouts per week, too many jumps per workout, incorrect form, jumping on hard surfaces, and using plyometrics at too early an age or without the necessary strength base. To avoid these injuries follow these guidelines.
- Preadolescent athletes should avoid plyometrics because of greater susceptibility to injury prior to puberty.
- Plyometrics should be postponed for athletes who do not have a sufficient base of strength. Avoid lower body plyometrics until the athlete is capable of Legs pressing 2.5 times their body weight and avoid upper body plyometrics until the athlete is able to complete 5 consecutive clap pushups.
- Athletes who do not respond well to instructions are also at greater risk of injury.
- Precede a plyometric workout with a general warm-up period consisting of walk-jog-stride-sprint cycles for one-half to three-quarters of a mile, followed by careful stretching exercises.
- Use footwear with good ankle and arch support, lateral stability, and a wide, non-slip sole.
- Perform plyometrics only on surfaces with good shock absorbing properties, such as soft grassy areas, well padded artificial turf, and wrestling mats. NEVER do plyometrics on asphalt or gymnasium floors.
- Boxes should be sturdy and have a non-slip top
- Depth jumping from objects that are too high increases the risk of injury, particularly to larger athletes, and prevents the rapid switch from eccentric to concentric activity. The average heights for depth jumps are 0.75-0.8 meters (27-30 inches). Athletes over 220 pounds should use heights of 0.5-0.75 meters (18-27 inches).
Once the safety precautions of plyometric training are understood and adhered too, a training program can be developed. First and foremost is the frequency of plyometric training. Plyometric training should be done no more than two days per week during the off-season and in only once during the in-season period. Since plyometric training is extremely strenuous, about 36-48 hours of rest is need to fully recover. Therefore, make plyometric training the very last session of the day. Also, due to the fatigue factor associated with this type of training, avoid doing heavy strength training on the same day as plyometric training unless lower body plyometric training is combined with upper body strength training or vice-versa.
To date, there is no magic number of jumps that produces the best results, but taking too few jumps is better than taking too many. Ideally, the number of jumps should not exceed 80-100 /session for beginners and athletes in early workouts, 100-120/session for intermediate athletes, and 120-140/session for advanced athletes who have completed at least 4 weeks of plyometric training.
The performance coach should also examine the intensity, or amount of stress placed upon the muscles and joints when prescribing plyometric exercise. Skipping movements provide minimum stress and are considered low-intensity exercises; box jumping, two foot take-off and landing exercises, high speed movements, and using additional weight, all increase the intensity of the workout. A sound program should progress from low-to high-intensity exercises.
Remember that as a performance coach, you are trying to improve your athlete’s power, not endurance. Thus, stress quality, not quantity to your athletes and allow adequate recovery between repetitions, sets, and workouts.