Differences among fastball, curveball, and change-up pitching biomechanics across various levels of baseball

TLDR

The study addresses ongoing debate over whether curveballs impose greater stress on young pitchers and whether professional pitchers exhibit fewer kinematic differences between fastballs and off‑speed pitches compared to lower‑level players. Researchers collected kinematic and kinetic data from 111 healthy pitchers across youth to major‑league levels while they threw fastballs, curveballs, and change‑ups in a biomechanics lab, then compared pitch‑type and level differences using repeated‑measures ANOVA. Fastballs produced higher shoulder and elbow kinetics than change‑ups, while curveball kinetics were comparable to both, and kinematic angles differed by pitch type at release and by competition level at foot contact, yet no interaction between pitch type and level was observed, indicating that pitch‑type differences are consistent across all levels and that curveballs are not more stressful for young pitchers.

Abstract

Controversy continues whether curveballs are stressful for young baseball pitchers. Furthermore, it is unproven whether professional baseball pitchers have fewer kinematic differences between fastballs and off-speed pitches than lower level pitchers. Kinematic and kinetic data were measured for 111 healthy baseball pitchers (26 youth, 21 high school, 20 collegiate, 26 minor league, and 18 major league level) throwing fastballs, curveballs, and change-ups in an indoor biomechanics laboratory with a high-speed, automated digitising system. Differences between pitch types and between competition levels were analysed with repeated measures ANOVA. Shoulder and elbow kinetics were greater in fastballs than in change-ups, while curveball kinetics were not different from the other two types of pitches. Kinematic angles at the instant of ball release varied between pitch types, while kinematic angles at the instant of lead foot contact varied between competition levels. There were no significant interactions between pitch type and competition level, meaning that kinetic and kinematic differences between pitch types did not vary by competition level. Like previous investigations, this study did not support the theory that curveballs are relatively more stressful for young pitchers. Although pitchers desire consistent kinematics, there were differences between pitch types, independent of competition level.