No effect of eccentric training on jumper’s knee in volleyball players during the competitive season: a randomized clinical trial. (2005)

Abstract
BACKGROUND: The effect of surgery on patellar tendinopathy (jumper’s knee) is questionable, and conservative treatment protocols have not been properly documented.

PURPOSE: The aim of this study was to investigate the effect of a newly developed eccentric training program for patellar tendinopathy in volleyball players during the competitive season.

STUDY DESIGN: Randomized clinical trial.

METHODS: Patients were recruited from male and female elite volleyball teams in Norway, and the diagnosis was based on clinical examination alone. Of 51 players diagnosed with patellar tendinopathy, 29 could be included in the study. The training group (n = 13) performed squats on a 25 degrees decline board as a home exercise program (3 x 15 repetitions twice daily) for a 12-week intervention period during the final half of the competitive season. The eccentric (downward) component was done on the affected leg. The control group (n = 16) trained as usual. The primary outcome was a symptom-based questionnaire developed specifically for patellar tendinopathy (Victorian Institute of Sport Assessment score), and patients were followed up before and after the intervention period, as well as after 6 and 30 weeks. All subjects self-recorded training to document their activity level (eccentric training, volleyball training, matches, other training).

RESULTS: There was no change in Victorian Institute of Sport Assessment score during the intervention period in the training (pre, 71.1 +/- 11.3; post, 70.2 +/- 15.4) or control group (pre, 76.4 +/- 12.1; post, 75.4 +/- 16.7), nor was there any change during the follow-up period at 6 weeks or 6 months. The training group completed 8.2 +/- 4.6 weekly sessions of eccentric training during the intervention period (59% of the recommended volume), and there was no difference between groups in training or competition load.

CONCLUSION: There was no effect on knee function from a 12-week program with eccentric training among a group of volleyball players with patellar tendinopathy who continued to train and compete during the treatment period. Whether the training would be effective if the patients did not participate in sports activity is not known.

Diagnosis:  Patellar Tendinopathy

Outcome:  VISA-P, static vertical jump, countermovement jump. No difference in pain level between eccentric group and controls. Small 1.2 cm change in countermovement jump for eccentric group, but no difference in control group and no difference in either group for static jump. No trend in either group towards increasing VISA-P in eccentric vs. control group. Both groups however had average VISA-P scores increase from low 60s during pretest to mid to low 70s on graph at week 12 and week 40.

When Assessed:  3 months and 6 months

Subjects:  13 in eccentric group and 16 in control group, ~ half male half female. Subjects from clubs in elite and 1st divisions for men and women in Norway. Had to have initial VISA-P score less than 80 points. Initial VISA-P score averaged 61 in eccentric group and 65 in control.

Protocol:  25 degree decline squats, 3 sets of 15 reps, intended 2x per day for 12 weeks, subjects with continued pain after 12 weeks were encouraged to continue with exercise, starting with bodyweight taking 2 seconds to lower to 90 degrees of knee flexion. Pain recommended to be at 5/10 and increased 5 kg increments when pain at 3-4/10. Both experimental and control group did PRE with rest of team 1.6 hours per week for eccentric group and 2.0 hours for control group. Volleyball training was 5.1 hours in eccentric group and 6.1 hours in control group. Only 6/13 of the eccentric group increased their load with final load averaging 4.2 kg. Eccentric group completed 59% of recommended volume.

Other Activity:  In season elite competitive volleyball players. Eccentric 1.4 and control 1.9 hours of weight training per week. Eccentric 5.8 hours per week of volleyball training and control 6.4 hours per week.

My Comments:  Cited 3 studies indicating patellar tendinopathy is present in 40-50% of high level volleyball players. This study is particularly interesting in that both groups did a little better over time even in the course of a competition season with VISA-P scores increasing from ~low 60s to 70s. There was certainly no increase in pain, nor a decline in function over time. These researchers interpreted the results as eccentric exercise not being effective for tendinopathy in season. Also, both groups strength trained during treatment, the control group more so, which while not detailed I would assume to include weight training to the lower extremities. With the 2009 Kongsgaard study indicating that more conventional PRE is as good or better than eccentric exercise for jumper’s knee/patellar tendinopathy, one might also explain the results of this study as mild success in both groups while training in season, rather than a failure of response of the eccentric group.