Superior results with eccentric compared to concentric quadriceps training in patients with jumper’s knee: a prospective randomized study. (2005)

Abstract
BACKGROUND: A recent study reported promising clinical results using eccentric quadriceps training on a decline board to treat jumper’s knee (patellar tendinosis).

METHODS: In this prospective study, athletes (mean age 25 years) with jumper’s knee were randomised to treatment with either painful eccentric or painful concentric quadriceps training on a decline board. Fifteen exercises were repeated three times, twice daily, 7 days/week, for 12 weeks. All patients ceased sporting activities for the first 6 weeks. Age, height, weight, and duration of symptoms were similar between groups. Visual analogue scales (VAS; patient estimation of pain during exercise) and Victorian Institute of Sport Assessment (VISA) scores, before and after treatment, and patient satisfaction, were used for evaluation.

RESULTS: In the eccentric group, for 9/10 tendons patients were satisfied with treatment, VAS decreased from 73 to 23 (p<0.005), and VISA score increased from 41 to 83 (p<0.005). In the concentric group, for 9/9 tendons patients were not satisfied, and there were no significant differences in VAS (from 74 to 68, p<0.34) and VISA score (from 41 to 37, p<0.34). At follow up (mean 32.6 months), patients in the eccentric group were still satisfied and sports active, but all patients in the concentric group had been treated surgically or by sclerosing injections.

CONCLUSIONS: In conclusion, eccentric, but not concentric, quadriceps training on a decline board, seems to reduce pain in jumper’s knee. The study aimed to include 20 patients in each group, but was stopped at the half time control because of poor results achieved in the concentric group.

Diagnosis:  Patellar Tendinitis

Outcome:  VAS during sporting activity (72.7 to 22.5) for eccentric group, concentric (74.3 to 68 but 3 patients dropped out) 9/10 eccentric patients satisfied, while 0/9 concentric patients were satisfied

When Assessed:  12 weeks

Subjects:  15 men, 2 women, athletes, ave age 25

Protocol:  Single leg squats on decline board to 70 degrees knee flexion, 3 sets of 15 reps, 2x per day 7 days per week

Other Activity:  Sport-specific training allowed after 6 weeks if there was no “severe pain.”

Chad’s Comments:   The need to avoid concentric exercise for tendinopathy is starting to be refuted in more recent studies, which are finding the concentric contraction is nearly, though not as, effective at decreasing pain as the eccentric component.  It will be interesting to see which way this discrepancy shakes out in the research.  However, in my physical therapy clinic I’ve noticed tendinopathy outcomes are as good or better (and the treatments are certainly easier to teach and perform) since I started adding the concentric component back into my treatment protocols.