Chris Novellino, Anthony Fava, Nicole Bordelon, Adam Nguyen, Katherine Everhart, Gretchen Oliver, FACSM. Auburn University, Auburn, AL.

BACKGROUND: Throwing curveballs (CV) has not been recommended for youth pitchers. Though, it has been shown in healthy pitchers that the CV produces less shoulder and elbow forces than fastballs (FB). It is unknown if these lower force patterns are exhibited among pitchers reporting pain. The purpose of this study was to examine shoulder and elbow forces between the CV and FB in youth pitchers with (W) and without (WO) upper extremity (UE) pain. METHODS: Eighteen youth baseball pitchers (12.9±1.4 y, 164.7±12.6 cm, 54.8±13.9 kg) performed three maximal effort CV and FB pitches for a strike at regulation distance (18.4 m). The fastest pitch was analyzed from stride foot contact to ball release. Participants were placed in the pain group if UE pain was reported on a health history questionnaire (n=9, 13.0±1.5 y, 165.1±11.5 cm, 55.1±13.8 kg), and were matched with pitchers who did not report pain (n=9, 12.8 ± 1.2 y, 164.4±13.6 cm, 54.6±14.1 kg). An electromagnetic tracking system was used to obtain kinematic and kinetic data. A 2x2 (pitch type) mixed design MANOVA was used to determine if there was a difference in CV and FB UE kinetics between pitchers W and WO UE pain. The between-subjects factor was pain (pain/no pain) and the within-subjects factor was pitch type (FB/CV). RESULTS: The mixed design MANOVA was not significant for pain (Wilks’ Λ=.934; p=.804) and the interaction between pain and pitch type (Wilks’ Λ=.893; p=.649). However, it was significant for pitch type (Wilks’ Λ=.543; p=.032). Univariate ANOVAs for pitch type were significant for elbow valgus [F(1, 16)=10.557; p=.005] and shoulder net force [F(1, 16)=6.824; p=.019]. It was not significant for elbow net force [F(1, 16)=4.141; p=.059]. Simple effects analyses showed elbow valgus moment was significantly greater in the FB (M=42.3 N·m, SD=5.4) compared to CV (M=32.3 N·m, SD=4.4). Shoulder net force was significantly higher in the CV (M=682 N, SD=69.2) compared to the FB (M=617 N, SD=71.2). CONCLUSION: There was no difference in FB and CV upper extremity kinetics between youth pitchers W and WO pain. Youth pitchers have traditionally been cautioned against throwing the CV. The current study revealed higher shoulder net forces during the CV. However, the elbow valgus moment was significantly less for the CV than the FB. Further research is needed to understand the relationship between breaking pitches and risk of injury.

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