A method for estimating elbow joint valgus stress using smartphone video

Abstract

In baseball, pitchers, at a wide range of levels are suffering from severe elbow injuries. To reduce the risk of developing elbow injuries, pitchers should find and grasp technical tips for minimizing the valgus stress. This technical improvement is not easily done primarily due to that the pitcher cannot self-recognize how large the valgus stress applied to the elbow joint during pitching. We present our first attempt to find a way to automatically estimate elbow joint valgus stress from the video-images taken by a smartphone. Pitching motions of 13 adults with various heights, weights and baseball experiences were recorded by a smartphone and a motion capture system simultaneously, and the elbow valgus stress of each pitch was computed for both data sets with an inverse dynamics approach. The comparisons of the corresponding two sets of valgus stresses showed that the average difference was 15.31%. In the future, the application of the smartphone including the user interface will be developed, and the servicing will be examined.