Dominant Arm Internal and External Rotation Strength is Related to Arm Pain in Youth Baseball Players.
Jeffrey Paskewitz, Fred Breidenbach, Philip Malloy and 2 others
PMID 39502540WHAT IT FOUND
In 65 youth baseball players, more frequent arm pain during throwing was weakly related to lower dominant shoulder external and internal rotation strength.
Shoulder range-of-motion measures did not track with pain. It does not show that strengthening shoulder muscles reduces pain.
Key findings
01Among 65 youth baseball players, dominant shoulder external rotation strength (r = -0.289, p = 0.020) and internal rotation strength (r = -0.262, p = 0.035) each had weak negative correlations with arm pain frequency during throwing.
02No significant correlations were found between arm pain frequency and other strength variables (p >= 0.118) or between arm pain frequency and shoulder range of motion, height, weight, or body mass index (p >= 0.124).
03At enrollment, arm pain frequency during throwing was reported as never by 21 (32.3%), rarely by 21 (32.3%), sometimes by 20 (30.8%), often by 2 (3.1%), and always by 1 (1.5%).
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What it does not show
The study used correlational analysis, so it cannot show that low shoulder strength caused arm pain. Shoulder strength values were not normalized, so height and weight may have affected the results. The sample was 65 players, which the authors describe as relatively small compared with other studies. Arm pain was self-reported at one timepoint, and the question did not specify a recall period. The outcome was frequency of arm pain during throwing, not a diagnosed injury or imaging finding.
Declared interests
The authors declared no conflicts of interest. The supplied text does not include a funding or sponsor statement.
The easy way to misread this
Do not conclude that strengthening shoulder muscles will reduce arm pain in youth baseball players. The study measured 65 players at one timepoint and found only weak correlations, so it cannot show that a strength program caused less pain.