Patellar tendonitis, or jumper’s knee, is the most frequent overuse injury in volleyball players because of the high frequency of jumping activity inherent in the sport. Jumping has been studied as a risk factor for injuries in many sports. In a study comparing injuries between different sports among Dutch school children, it was found that those sports with a higher “jump rate” had a higher risk of injury during the course of one year (Backx, 1991). While it is still not possible to predict with certainty which athletes will suffer from jumper’s knee during the course of the season, recent studies have shed some light on which players may be particularly at risk for this injury.
Elite club volleyball players in Norway were studied and it was determined that those athletes who could generate the greatest power during the “counter-movement jump” (similar to a block jump) were more likely to be symptomatic with patellar tendonitis (Engebretsen, 1996). Other researchers analyzed the knee joint dynamics during jumping among Canadian national team players. They also found that those athletes who generated the highest rate of force had the highest impact forces upon landing, making them more susceptible to jumper’s knee. Other variables that correlated with development of patellar tendonitis included increased external tibial torsion at take-off for the spike jump and deep knee flexion angles at take-off and landing (Richards, 1996).
There is also some older research on Italian club players which demonstrates that jumper’s knee was more common in those who play more often than four times a week and are between 20-25 years of age.William W. Briner, Jr
Players who had been involved in volleyball for two to five years were also more likely to have symptoms (Ferretti, 1983). Plyometric training has not been specifically associated with an increased incidence of jumper’s knee in past studies. Perhaps that is because the populations that were studied were performing their plyometric training under close supervision (Ferretti). These researches also noted that patellar tendonitis is less likely to occur in those who train on relatively softer surfaces. They found a lower incidence of jumper’s knee among players who trained on wood as compared to harder concrete or linoleum surfaces. Our own data (from U.S. Olympic Festival athletes in 1995) demonstrates that volleyball injuries in general and patellar tendonitis in particular were about five times less likely to occur on sand as compared to hard indoor court surfaces.
Some basic recommendations for injury prevention that could be made from these data might include the following:
1) Since the players who are already the highest jumpers are the ones most likely to develop patellar tendonitis, it may be advisable to limit their jump training, especially if symptoms occur. These athletes will not benefit as much from jump training, anyway.
2) Watch for players who bend their knees more than 90 degrees at take-off or landing, as well as those who turn their lower legs and feet outward when they jump. They should be coached to avoid these tendencies.
3) Try to do as much jumping as possible on softer surfaces, such as sand.
- Backx, F.J.G., H.J.M. Beijer and W.B.M. Erich. (1991). Injuries in high-risk persons and high-risk sports. The American Journal of Sports Medicine, 19(2): 124-130.
- Ferretti, A., E. Ippolito, P. Mariani and G. Puddu. (1983). Jumper’s knee. The American Journal of Sports Medicine, 11(2); 58-62.
- Lian, O., L. Engebretsen L, R.V. Ovrebo and R. Bahr. (1996). Characteristics of the leg extensors in male volleyball players with jumper’s knee. The American Journal of Sports Medicine, 24(3); 380.
- Richards, D.P., S.V. Ajenian, J.P. Wiley and R.F. Zernicke. (1996). Knee joint dynamics predict patellar tendonitis in elite volleyball players. The American Journal of Sports Medicine, 24(5); 676-683.
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