Acute effects of softball pitching to fatigue on the glenohumeral internal rotation range of motion

Abstract

BACKGROUND: The effects of baseball pitching on the glenohumeral joint (GHJ) range of motion (ROM) have been widely studied. Specifically, internal rotation (IR) ROM reduction of the pitching arm, an adaptation to repeated overhead throwing, is linked to increased risk of injuries in baseball pitchers. However, there is a lack of literature on the effects of softball pitching on the GHJ ROM. HYPOTHESIS: Softball pitching to fatigue will result in significant reduction of GHJ supine IR ROM. DESIGN: Test–retest, quasi-experimental study. METHODS: Twelve softball pitchers (age: 19.5 ± 1.8 years) volunteered to participate in this study. GHJ ROM in supine IR, horizontal adduction, low flexion (shoulder joint flexed to 60°; added IR), extension with IR (shoulder joint abducted to 60° in the plane of scapula and then horizontally abducted 90° with the elbow maintained in 90° flexion; add GH IR), and supine external rotation were compared before and after a single bout of softball pitching to fatigue or a maximum of 100 pitches, whichever occurred first. RESULTS: Maximum ROM change post softball pitching was observed in horizontal adduction but not in supine IR. CONCLUSIONS: Maximum ROM change was observed in horizontal adduction. Supine IR ROM measurement may not be appropriate for assessing softball pitchers' shoulder ROM because this measurement was not affected by the softball pitching.