A 2022 study in The Journal of Applied Biomechanics found that in collegiate and pro pitchers, changing ball weight (3 to 7 oz) significantly affected velocity and segment speeds—lighter balls sped everything up, heavier balls slowed it down—without increasing measured shoulder or elbow kinetics during the acceleration phase. The key caveat is that the study didn’t measure the deceleration phase, where heavier implements can raise eccentric demands even if acceleration torques stay the same. It also didn’t specify whether the implements were plyoballs or hard leather weighted balls, a detail that matters when translating the findings into real training decisions.
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