Lateral ankle sprain: isokinetic test reliability and comparison between invertors and evertors

Objective. Evaluate reliability of isokinetic tests for inversion and eversion in individuals with recurrent lateral ankle sprain and compare inversion to eversion muscle performance in the same ankles. Design. Reliability was evaluated by comparing the results of two ankle inversion/eversion isokinetic tests. Inversion and eversion were compared with the results presented by the tests. Background. Previous studies showed reliable isokinetic tests for ankles with no sprain history. It is unknown if such tests can also be performed in lateral sprained ankles. It is unclear whether there is difference between invertors and evertors in these ankles. Methods. Eleven men with recurrent ankle lateral sprain in one limb were tested using an isokinetic dynamometer. The tests consisted of 5 cycles of maximal contraction in 30°/s and 120°/s. Both injured and noninjured ankles were tested. Peak torque was recorded for analysis. Results. The tests are reliable and intraclass coefficient correlation varied from 0.71 to 0.95. Invertors generated higher peak torques than evertors (P=0.03) when injured ankles were tested at 120°/s. Conclusions. Isokinetic inversion/eversion tests showed to be reliable. A decrease in peak torques can be seen during higher velocity tests. The only difference between invertors and evertors was seen when injured ankles were tested at 120°/s. In this case invertors showed higher peak torques.