Glenohumeral internal rotation decreases over time for major league pitchers
Kibler WB. Clin Orthop Relat Res. 2011. doi: 10.1007/s11999-011-2217-z
Glenohumeral internal rotation decreased over a 4-day pitching period for major league pitchers, according to University of Kentucky researchers.
“Although decreased GIR [glenohumeral internal rotation] has been documented after throwing, its time course for recovery and the effect of pitching role have not,” the authors wrote in their abstract.
The researchers measured 45 Houston Astros starting and relief pitchers not only for GIR, but also for glenohumeral external rotation (GER) and total arc of motion (TAM), the combined GIR and GER. They calculated the measurements at five different time points, before throwing, after throwing and at 24, 48 and 72 hours later.
The GIR decreased and did not go back to baseline. The GER was not significant and the TAM decreased at 72 hours. Relief pitchers showed increased GIR, GER and TAM at all time points, but there was no difference in change between groups at all time points. “Pitching role did not affect the short-term changes,” according to the abstract.
“GIR changes should be expected after an acute throwing episode and conditioning and recovery programs should be used to modify the changes,” the authors wrote. “Because GIR is dynamic, studies on GIR should specifically state when during the pitching cycle the measurement was obtained.”