Change in Grip and Pinch Strength Over the Course of a Game in Professional Baseball Pitchers

Background: Baseball pitching injuries can be related to fatigue. Changes in grip and pinch strength over the course of professional baseball games are unknown.

Hypothesis: Grip and pinch strength will decrease as the number of innings pitched increases; injured pitchers will have a lower grip strength than uninjured pitchers.

Study design: Prospective cohort study.

Level of evidence: Level 3.

Methods: Minor league pitchers for 1 affiliate of a single organization were included. Changes in dominant and nondominant grip, and middle and index finger pincer strength were recorded pregame and after each inning, and compared between players who sustained a shoulder/elbow injury and those who did not.

Results: Of 41 pitchers included, 6 sustained a shoulder (n = 2) or elbow (n = 4) injury during the study period. Average grip strength for all pitchers was 124.5 ± 17 lb pregame and increased slightly after the first inning (125.2 ± 17 lb), then declined slowly after the second (120.7 ± 18.5 lb), third (119.2 ± 24 lb), and fourth (113.1 ± 19.6 lb) innings. There was a slight uptick in grip strength in the fifth (118.5 ± 23.6 lb) and sixth (121.3 ± 21.8 lb) innings, but pregame levels were not reached. Evaluating uninjured and injured pitchers, the grip strength of injured pitchers was lower at all timepoints. As a percentage of uninjured pitchers grip strength, injured pitcher grip strength was 94.8% pregame, and 97.9%, 95.4%, 81.8%, 87.7%, 82.3%, and 74.5% after the first to sixth innings, respectively.

Conclusion: Dominant arm grip strength generally declined over the course of a game in professional baseball pitchers. Injured pitchers generally had weaker grip strength and a steeper decline in grip strength during games compared with uninjured pitchers.

Clinical relevance: Incremental loss of grip strength may increase injury risk in professional baseball pitchers.