Concentric and eccentric quadriceps torque in pre-adolescent males.

The purpose of this study was to evaluate the applicability of using the Kin Com (Chattecx Corp., Chattanooga, TN) isokinetic machine to measure concentric and eccentric quadriceps torque in a group of 12 healthy male volunteers aged 10-12 years. Each individual was tested by an experienced physiotherapist using a 60 degree per second velocity mode according to our standardized protocol. Average and peak torque values for concentric and eccentric contractions of the quadriceps were recorded; based upon the best of three maximum effort trials on each lower extremity. Retesting was performed on a randomly selected sub-group in an identical manner two weeks later. Our results showed no statistically significant difference between the original and retest values using the method error of repeated measurements and paired t-test analyses. Eccentric peak torque was greater on average than concentric. This was significant with p-values of 0.01 for the non-dominant quadriceps and 0.002 for the dominant side (paired t-test). There was no significant difference between the dominant and non-dominant sides. In conclusion, eccentric muscle testing has been reliably quantitated for the first time in children. This study has shown a practical and reproducible method of quantitative muscle strength assessment.