Assessment of Correlation between Electrogoniometer Measurements and Sports-Specific Movement in Karate Elites

To examine the intra-rater reliability of knee movement data in sagital plane obtained from electrogoniometer (EGM) in a basic, sport-specific task of karate.

A total of 23 elite karate athletes (13 females and 10 males; mean age of 16.10±1.26 yrs) participated in this study. The task was defined as performing three consecutive Zenkutsu-dachi in two sessions. The used EGM was a twin axis of Biometrics company. EGM curves were plotted in MATLAB software separately. The indices of three points in the plots corresponding to extremes of flexion and extension of knee in the first dachi were determined. There was also another (forth) point which was not in extremes of movement. As it was repeated in all curves, it was perceived as a biomechanical event and was assessed. The phases of movement between the points were scaled between 0 to 100% of activity.

Repeatability of the forth point index was assessed by intraclass correlation method. Intraclass correlation of the ratio in the first testing session was 0.666 and in second was 0.448. The interval between points were considered as phases of movement. After determining three phases of dachi, it was shown that these phases pertained a specific ratio of the total plot which were 48%, 36% and 16% of total respectively.

Dachi could be divided into three distinct phases; each of them should constitute a specific percent of the total in an elite athlete.