Identifying influential motion patterns in javelin throwing using principal component analysis

Understanding how a series of motions is organized by the relationship between various body segments when performing a javelin throw may provide useful insights to improve the technique and optimize performance. Waveform reconstruction helps determine the details of motion patterns based on the relationships between various body segments. Therefore, we aimed to utilize principal component and waveform analyses to identify and describe the specific motion patterns that directly affect the throwing distance of javelins. The best attempts of 32 male javelin throwers participating in college athletic competitions were analysed. Principal component analysis was performed on kinematic variables obtained via three-dimensional motion analysis. The first 13 principal components, accounting for 82.19% of the variance in throwing motion, were extracted for analysis. Of these, only one principal component (PC1) was identified as the motion pattern affecting the throwing distance. PC1 was associated with an increase in run-up velocity at release. In addition, the reconstructed waveform of PC1 showed distinct characteristic motion patterns in good and poor throwers.