Context: The deceleration phase of the throwing motion creates large distraction forces at the shoulder, which may result in posterior shoulder tightness and ensuing alterations in shoulder range of motion (ROM) and may result in an increased risk of shoulder injury. Researchers have hypothesized that various stretching options increase this motion, but few data on the effectiveness of treating such tightness are available.
Objective: To evaluate the acute effects of "sleeper stretches" on shoulder ROM.
Design: Descriptive with repeated measures.
Setting: Biomechanics laboratory and 2 separate collegiate athletic training facilities.
Patients or other participants: Thirty-three National Collegiate Athletic Association Division I baseball players (15 pitchers, 18 position players; age = 19.8 +/- 1.3 years, height = 184.7 +/- 6.4 cm, mass = 84.8 +/- 7.7 kg) and 33 physically active male college students (age = 20.1 +/- 0.6 years, height = 179.6 +/- 6.6 cm, mass = 83.4 +/- 11.3 kg) who reported no recent participation (within 5 years) in overhead athletic activities.
Intervention(s): Range-of-motion measurements of the dominant shoulder were assessed before and after completion of 3 sets of 30-second passive sleeper stretches among the baseball players. The ROM measurements in the nonthrower group were taken using identical methods as those in the baseball group, but this group did not perform any stretch or movement between measurements.
Main outcome measure(s): Internal and external glenohumeral rotation ROM and posterior shoulder motion (glenohumeral horizontal adduction).
Results: In the baseball group, posterior shoulder tightness, internal rotation ROM, and external rotation ROM were -3.5 degrees +/- 7.7 degrees , 43.8 degrees +/- 9.5 degrees , and 118.6 degrees +/- 10.9 degrees , respectively, before the stretches and were -1.2 degrees +/- 8.8 degrees , 46.9 degrees +/- 9.8 degrees , and 119.2 degrees +/- 11.0 degrees , respectively, after the stretches. These data revealed increases in posterior shoulder motion (P = .01, effect size = 0.30) and in internal shoulder rotation (P = .003, effect size = 0.32) after application of the stretches. No other differences were observed in the baseball group, and no differences were noted in the nonthrower group.
Conclusions: Based on our results, the sleeper stretches produced a statistically significant acute increase in posterior shoulder flexibility. However, this change in motion may not be clinically significant.
Keywords: flexibility; soft tissue; throwing athletes.