Abstract
Objectives:
The aim of this study was to determine whether a static stretch of posterior deltoid could reduce the glenohumeral internal rotation deficit (GIRD) and the total arc of movement deficit (TAMD) in professional swimmers after competition.
Methods:
Participants: A total of 74 professional swimmers aged from 16-33 years volunteered to participated in the study. Their competition experience were more than 2 years at national level. All the subjects were informed in written and verbal form and signed their informed consent before being assessed. Design and procedures: A randomized repeated measures design was used to assess the glenohumeral rotation in 3 moments: prior to the race, just after finishing their trial and after performing a static passive stretch of posterior deltoid muscles of 90-sec. In randomized order the computer selected 20 subjects as a control group (CG) who didn’t perform the stretching. The experimental group (EG) included 54 swimmers. The glenohumeral internal and external rotation (IR and ER) were recorded by a video camera (IPhone 6 S, version 10.1), in sagittal plane, with the center of the screen at shoulder high. Subjects were laying on supine position over a massage table, with the glenohumeral joint at 90° of abduction, the elbow at 90° of flexion, and the researcher controlling the scapula movements by pushing the shoulder over coracoid apophasis. The App Thechnique (Ubersense ©) was used to measure the glenohumeral rotation degrees between the vertical line (controlled by a plumb) and the forearm segment.
Results:
The multifactorial ANOVA showed that there were significant differences on GIRD and TAMD between the experimental and the control group performing the stretching F(2,70)=49.150, P=0.000, η2p=0.992. The experimental group reduced the GIRD a16.2% and the TAMD a 6.7%. The dominant IR mean values changed significantly from 66.3±12.5 to 79.2±10.4 degrees for EG (P=0.00) and non-significantly for CG, from 74.6±12.7 to 77.6±13.9 degrees (P=0.11). The dominant TAM means changed significantly in EG from 173.2±16.8 to 192.0±17.0 degrees (P=0.00) and non- significantly for CG 181.5±21.7 to 188.2±23.3 degrees (P=0.12).
Conclusion:
To apply a static passive stretching on posterior deltoid during 90-sec reduced GIRD and the TAMD in professional swimmers after competition, which suggest a reduced risk of shoulder injury in these overhead athletes.