The primary purpose of this study is to determine if the loss of internal rotation following a throwing session is best restored through soft tissue stretching with the sleeper stretch or with scapular repositioning with the 90/90 hip lift with balloon blow exercise. This study will progress the body of research related to internal rotation deficits with regards to baseball throwers. The research will be relevant to clinicians who treat patients with baseball players with internal rotation loss.

High school baseball players will be the targeted subjects for this study. They will perform two exercises (one per week) designed to increase shoulder internal rotation over the course of three weeks with one week of rest between intervention weeks. The primary outcome will be shoulder internal rotation range of motion improvements over the course of one week's time. There are no known adverse risks to either intervention.

Purpose of the Study: The primary purpose of this study is to determine if the loss of internal rotation following a throwing session is best restored through soft tissue stretching with the sleeper stretch or with scapular repositioning with the 90/90 hip lift with balloon blow exercise. This study will progress the body of research related to internal rotation deficits with regards to baseball throwers. The research will be relevant to clinicians who treat patients with baseball players with internal rotation loss.

Specific Aim: To determine if the glenohumeral internal rotation deficit (GIRD) is more effectively restored following a throwing session by performing the sleeper stretch (SS) or the 90/90 hip lift with balloon blow exercise (BBE).

Hypothesis: BBE will improve GIRD more effectively and quickly than the SS.

This is a prospective randomized trial comparing the efficacy of two exercises designed to improve shoulder internal rotation. Subjects meeting study criteria will be randomly allocated to each group as shown in the following CONSORT allocation diagram. Randomization will be performed via random number generator.

Each subject will participate in two week-long interventions with at least one week separating the two intervention weeks. During the week of intervention, the subject will have his baseline IR measured. He will then be instructed in how to perform a single exercise designed to improve internal rotation range of motion. Approximately half of the subjects will perform the Sleeper Stretch the first week, then the Balloon Blow Exercise the second week. The remaining group of subjects will perform the Balloon Blow Exercise during the first week, then the Sleeper Stretch the second week. Both exercises will be instructed by a physical therapist who commonly prescribes the exercises in the clinical setting. A written handout detailing the exercise instructions, frequency, and duration of the stretch will be provided for the subjects' reference (submitted with IRB application). The subject will perform this exercise throughout the week as directed by study personnel. Baseline measures of glenohumeral internal rotation (IR) with the shoulder positioned at 90 degrees of abduction in the scapular plane will be obtained using a goniometer, as described by Manske. These measurements will be repeated after the initiation of the intervention exercise at the following intervals: 2 hours, 1 day, 2 days, 3 days and 4 days. All measures of IR will be taken 3 times and the average of the three measures used in data analysis. The investigator performing the measures will be blinded to participant group assignment. When the subject completes both intervention weeks, he will be asked if he had a personal preference for either exercise.

Inclusion Criteria:

1. Active participation in competitive high school baseball at the time of study participation.
2. Ability to read, write, and speak the English language.

Exclusion Criteria:

1. Prior surgery to the dominant (throwing) shoulder
2. Any current upper extremity injury or limitation that restricts full participation in sport
3. Latex allergy secondary to use of latex material of the balloon
4. Any known inability to be physically present for daily testing during the weeks of the study