Rafael F. Escamilla, PhD, PT, CSCS, FACS; Kyle Yamashiro, DPT, PT, CSCS; Tony Mikla, DPT, MSPT, CSCS, XPS; Jeff Collins, ATC; Keith Lieppman, BA; and James R. Andrews, MD
Investigation performed at California State University, Sacramento
A glenohumeral internal rotation (IR) deficit or a total rotational motion (IR plus external rotation [ER]) deficit in the throwing shoulder, compared with the non-throwing shoulder, has been shown to increase the risk of shoulder and elbow injuries. After a pitching session, both IR and total rotational motion deficits have been shown to occur naturally for an extended period of time in asymptomatic pitchers, but it is unclear how to best control these deficits between pitching sessions.
The purpose of this study was to determine whether performing a short-duration stretching/calisthenics drill after pitching will result in an increase in IR, ER, total rotational motion, and elbow extension in professional baseball pitchers. It was hypothesized that these shoulder and elbow passive range of motion (PROM) measurements would all decrease after pitching but would subsequently return to pre-pitching values after the short-duration stretching/calisthenics drill.
Controlled laboratory study.
A convenience sample of 20 male professional baseball pitchers served as study participants. The following sequence of activities was performed for all participants: (1) a 5- to 10-minute dynamic warm-up consisting of running and light throwing, (2) elbow extension and IR and ER PROM measurements taken before pitching, (3) 40 full-effort pitches off the pitching mound, (4) 8 minutes of rest, (5) elbow extension and IR and ER PROM measurements taken after pitching, (6) a short-duration stretching/calisthenics drill (two-out drill), and (7) elbow extension and IR and ER PROM measurements taken after the two-out drill. A one-way repeated measures analysis of variance (P\.05) was employed to assess differences in elbow extension, IR, ER, and total rotational motion in the three measurement conditions (pre-pitching, post-pitching, and post-drill). To assess intra-rater and inter-rater reliability, intra-class correlation coefficients (ICCs) were calculated, and the measurement error was calculated using the standard error of measurement (SEM).
Significant differences were observed among the three conditions for ER (P = .002), IR (P = .027), and total rotational motion (P\.001), but there was no significant difference in elbow extension (P = .117). Bonferroni post hoc analyses revealed (1) significantly greater ER during pre-pitching and post-drill versus the post-pitching condition (94_ 6 7_ [pre-pitching] and 94_ 6 8_ [post-drill] vs 88_ 6 8_; P = .010 and .005, respectively), (2) significantly greater IR during pre-pitching and post-drill versus the post-pitching condition (36_ 6 10_ [pre-pitching] and 35_ 6 9_ [post-drill] vs 30_ 6 10_; P = .034 and .043, respectively), and (3) significantly greater total rotational motion during pre-pitching and post-drill versus the post-pitching condition (129_ 6 13_ [pre-pitching] and 129_ 6 13_ [post-drill] vs119_ 6 13_; P = .034 and .004, respectively). There were no significant differences in ER, IR, or total rotational motion between the pre-pitching and post-drill conditions (P . .999 for all). The intra-rater reliability (ICC3,1) was 0.91 for ER (SEM, 1.3_) and 0.90 for IR (SEM, 1.9_), and the inter-rater reliability (ICC2,1) was 0.81 for ER (SEM, 3.3_) and 0.77 for IR (SEM, 4.3_).
After a 40-pitch bullpen session, IR and ER PROM, as well as total rotational motion, were significantly lower than pre-pitching values; however, these deficits were restored back to their pre-pitching levels after the players performed the two-out drill, which may increase pitching performance and decrease the risk of shoulder and elbow injuries. More research is needed to test these hypotheses and assess the clinical efficacy of the two-out drill.
The findings from the current study will assist clinicians to better understand the positive effects of pitchers performing short duration stretching/calisthenics drills on shoulder internal and external rotation range of motion between innings when pitching in a game.
Please look out for Part 2 next month when we’ll discuss the current literature surrounding shoulder motion and the seven stretches performed in the two-out drill.