The effect of an eccentric-type exercise versus a concentric-type exercise in the management of chronic Achilles tendonitis
Creators: name: Niesen-Vertommen, Sherri
Publisher: name: University of British Columbia
Year: 2010

description: The main purpose of this study was to determine which method of tendon rehabilitation - the "eccentric ankle drop" exercise or the universal gym "concentric plantarflexion/dorsiflexion" exercise - produced a more effective result in terms of recovery in the treatment of chronic Achilles tendonitis. Seventeen subjects with chronic Achilles tendonitis were studied. They were selected on the basis that they had a history of athletic participation, and have had the symptoms of Achilles tendonitis greater than three weeks. Subjects were assigned to either of two groups: training using the "eccentric ankle drop" exercise or training using the "concentric plantarflexion/ dorsiflexion" exercise. Subjects were clinically examined by a physician and referred to the study, then placed on a twelve week exercise program. They were examined and tested at 0, 4, 8 and 12 weeks. Testing included the following variables: average and peak torque measured on the KIN/COM Isokinetic Dynamometer at 3 0 and 50 degrees per second, and for plantarflexor concentric and eccentric muscle contractions, a subjective evaluation of pain and return to activity rated on a scale from 1 to 10. The results showed the "eccentric ankle drop" exercise did not significantly increase in average or peak torque values at either velocity of 3 0 or 50 degrees per second more so than the "concentric plantarflexion/dorsiflexion" exercise. However, the eccentric group did demonstrate larger gains in both torque value compared to the concentric group. The plantarflexor torque values on the whole increased in a linear fashion at both velocities for both groups similarly, as indicated by the highly significant trend analysis (p&lt;.001). There was a significant difference seen in pain ratings between the groups averaged over the four testing sessions (p&lt;.01) with the eccentric group decreasing in pain more than the concentric group. Also, the eccentric exercise group produced three times as many "pain free" subjects at the end of the program than the concentric group. There was not a significant difference observed between the eccentric exercise group and the concentric exercise group with the return to activity effect. However the eccentric group over the twelve week period demonstrated a quicker return to preinjury activity than did the concentric group. The eccentric group also produced four times as many full return to preinjury activity level subjects by the end of the program than did the concentric group. Also the return to activity effect increased in a linear fashion for both groups similarly, as indicated by the highly significant trend analysis (P&lt;.001). Although no statistical significance was found between the two exercise groups (except for pain levels), the subjective measures favor the use of the eccentric exercise. Thus from a clinical standpoint, the eccentric exercise can be recommended as a more positive approach toward the conservative management of chronic Achilles tendonitis.