Effect of a Novel Stretching Technique on Shoulder Range of Motion and Voluntary Contraction in Overhead Athletes With Glenohumeral Internal Rotation Deficits "GIRD"

To examine and compare the effect of a novel stretching technique and traditional stretching on glenohumeral range of motion, strength, maximum voluntary contraction, pain, and subject satisfaction in overhead athletes with glenohumeral internal rotation deficits through a randomized clinical study. The investigators hypothesize that this type of novel intervention will help subjects with GIRD to restore range of motion, experience less pain and maintain the strength and motor unit recruitment following the novel intervention. This will help us to assess the potential beneficial effect of such intervention and to fill the gap in knowledge and help health care professionals to adequately select the right treatment modality.

Independent Variable

• Type of Intervention:

• Traditional Stretching (Modified Sleep Stretch). VS
• Novel Stretching (Active Shoulder Internal Rotation while Bridging) 2. Time
• Pre VS post intervention Dependent Variables

• Glenohumeral internal rotation ROM
• Maximal glenohumeral external rotation isometric strength.
• Mean motor unit recruitment (EMG) of the glenohumeral external rotator (infraspinatus) and internal rotators (pectoralis major and latissumus dorsi)
• Pain
• Subject satisfaction

Instrumentation :

• Glenohumeral internal & external rotation ROM: will be measured at baseline and at week four-post intervention for all participants. We will use the digital inclinometer. Research by (Kolber et al.,2011 ) showed this instrument to be reliable with an intra-rater ICC =0.87 and inter-rater ICC =0.93
• Electronic push/pull dynamometer: At the end feel ROM, and before ROM is measured, the therapist will apply the same amount of pressure to all subjects to ensure reliable/ valid ROM measurements.
• Maximal Glenohumeral External Rotation Isometric Strength will be measured using a MicroFET2 handheld digital dynamometer. This device was shown to be reliable with an intra-rater ICC =0.85 and inter-rater ICC =0.85.
• Maximum Voluntary Contraction: will be measured using a 44 Delsys Bagnoli portable surface electromyography (sEMG) system.
• Pain: will be measured using the Numeric Pain Rating Scale (NPRS). The NPRS has shown to have a valid, reliable and appropriate for use in clinical practice

Procedures:

All participants will perform the static stretching (SS) conditions by themselves. The two stretching techniques will be home-based program.

Inclusion criteria

• Participants must be between the age of 18 and 45.
• Perform overhead sports activities in the past 3 months.
• Participants are required to display ≥ 20° less glenohumeral internal rotation ROM in their dominant shoulder compare to the non- dominate shoulder.
• Participants will be included with or without pain during shoulder activities.

Exclusion criteria

• Will exclude participants who are still recovering from previous surgery of the shoulder and elbow complex in the past 3 months, and currently receiving medical intervention for the shoulder.