Development of Throwing Form Check System for Prevention and Treatment of Little League Elbow

Abstract

This paper proposed a new measurement system in order to evaluate the angle of the elbow and the shoulder in three dimension while throwing a baseball. The sensor-boards of the system are composed of a three dimensional accelerometer, a transmitter, a microcomputer and a Lithium-Ion battery. The sensor-boards were stuck by tape in parts of the body and transmit information about acceleration of the body motion. The transmitted accelerate signal are calculated in the PC with the originally developed software. This system was compared with the commercial three dimensional motion analysis system “Vicon”using high-speed cameras, and with the conventional form check method, which had been done clinically. In the comparison of shoulder joint angle with “Vicon”and the developed system, the correlation coefficient was 0.8. The inclination of the regression line was 0.48. In order to evaluate the throwing form with the conventional form check method accurately, it is required in experienced skill for the investigator. Therefore, it is preferable to apply the system with quantity evaluation in the field of sports. Using the new measurement system, it was able to check the throwing form for the little league elbow in the limited range. It will be necessary to improve the accuracy of the system and expand the range of the measurement to the lower half of the body, in the future. Then there is a possibility that the kinematic pattern of the whole body can be observed.