In Cheng et al. (2026) brand new article titled The Softball Pitching Plane (SPP): A Reliable Geometric Descriptor of Arm Trajectory and Its Relationship to Ball Velocity in Adolescent Pitchers, 49 adolescent softball pitchers (middle school and high school aged) to see if the path of the throwing arm during a windmill pitch could be described using a single geometric plane and whether staying closer to that plane was related to throwing the ball faster. Each pitcher threw 15 full-effort drop-ball pitches after completing a warm-up. Body movement was recorded using a 15-sensor electromagnetic motion-capture system, and pitch speed was measured with a Rapsodo pitching device. The researchers tracked the three-dimensional movement of the shoulder, arm, elbow, wrist, and hand. They used a mathematical method to fit a “best-fit” plane to the arm path during different parts of the pitch and found that the downswing-to-ball-release phase worked best. They then measured how much the arm moved away from this plane and used statistical models to see if this deviation was related to ball velocity.
They found:
- The wrist path during downswing to ball release fit a plane better than any other phase of the pitch
- The Softball Pitching Plane showed high reliability, meaning pitchers were consistent across trials
- Reliability values (ICC) ranged from 0.81 to 0.90
- Greater deviation from the pitching plane was linked to slower pitch velocity
- Within a pitcher: pitches that strayed more from the plane were slower
- Between pitchers: pitchers with more overall deviation threw slower on average
- For every 1 cm increase in deviation, pitch speed decreased by about 0.1–0.4 km/h
- The orientation of the plane (slope and direction) did not affect pitch velocity
Implications: The researchers concluded that the windmill softball pitch can be reliably described using a single pitching plane during the late part of the motion, and that staying close to this plane is related to throwing the ball faster. This suggests that efficient pitchers move their arms in a more consistent and organized way, without unnecessary side-to-side motion. The authors explain that movement earlier in the pitch is more variable and less focused on producing speed, which is why the downswing-to-release phase best represents performance. They also emphasize that there is no single “correct” arm slot, since the plane’s angle and direction did not matter for velocity. Instead, consistency of movement appears to be more important than exact positioning. The authors note that this study focused only on adolescent pitchers and one pitch type, so future research should test whether these findings apply to older athletes, different pitches, fatigue, or injury risk. Overall, the Softball Pitching Plane offers a new way to understand pitching efficiency by focusing on the quality and consistency of the arm path rather than individual joint angles.
Also…
There are a couple of themes that I have noticed as I have dug deeper into strength and conditioning: 1. Building based on the physical needs of the task (hitting, pitching, etc) and 2. The foundation of every program is eerily similar. This post by Gerry DeFillipo shows that football prep is very similar to baseball/softball.