Exploring The Impact Of Pitch Angle On Pitcher Performance Through Cluster Analysis

: Baseball pitchers play a crucial role in determining the outcome of a game. During the pitching process, pitchers often generate maximum shoulder external rotation during the late cocking phase and transition into the acceleration phase, which affects both ball speed and accuracy. The rotation angle can involve the creation of kinetic energy, but it also influences the pitcher's accuracy and elevates the likelihood of injury. PURPOSE: This study investigates the differences in joint angles of the dominant side between elite and non-elite college pitchers. METHODS: Thirty-four college baseball pitchers were recruited without neurological or muscular injuries (average age 20.48 ± 0.9 years). We measured the joint range of motion and grip strength on the dominant side. Pitching performance was evaluated utilizing Rapsodo pitching technology during live pitching sessions. Cluster analysis based on ball speed and the spin rate was used to categorize pitchers into elite and non-elite groups. In addition, independent t-tests were performed to assess the differences in joint flexibility between the two groups. RESULTS: Based on their pitching performance, pitchers were clustered into elite (n = 23) and non-elite (n = 11). Elite pitchers had an average ball speed of 135.3 km/h and a spin rate of 2253.9 RPM, while non-elite pitchers had an average ball speed of 125.3 km/h and a spin rate of 1858.7 RPM. Elite pitchers also demonstrated significantly lower shoulder internal rotation, shoulder external rotation, and hip internal rotation angles on their dominant side (ps < .05). CONCLUSION: Our findings indicate that differences in ball speed and spin rate between elite and non-elite pitchers are not primarily associated with the flexibility of the shoulder and hip joints. Instead, the results indicate that lower shoulder internal rotation, shoulder external rotation, and hip internal rotation angles on the dominant side may be critical factors in pitching performance. KEYWORDS: flexibility, college baseball player, risk of injury