Monitoring the improvement of muscle performance using isokinetic dynamometry: A comparative analysis based on the full range of motion vs. the valid isokinetic sector

BACKGROUND: Isokinetic dynamometers measure moment and calculate work and power values, which are generally used to interpret muscle performance. OBJECTIVE: This study aimed to determine the differences of peak moment (PM), work, and power between FRoM and calculated valid isokinetic sector (VIS) data to define the possibility of the misinterpretation of isokinetic dynamometer data. METHODS: Fourteen professional male soccer players who had ACL reconstruction were recruited to the muscle strengthening program which was conducted four days a week for six weeks with increasing training intensity each week. Isokinetic muscle peak moment, work, and power of knee extensors and flexors were measured at angular velocities of 60, 120, 180 and 240 degrees/s. RESULTS: The results of the standard full-RoM (FRoM) report were compared with the calculated VIS data. Analyses of the FRoM data showed that PM, work, and power values for both extensor and flexor muscle groups improved significantly. However, a comparison of FRoM and VIS data showed significant differences for the work and power values at 120, 180 and 240 degrees/s. CONCLUSION: The evaluation of FRoM isokinetic data may cause improper interpretations in muscle performance, particularly for contractions with higher angular velocities.