Author Names: Reed M., Begalle R., Laudner K.
Reviewer Name: Kendall Bietsch, SPT
Reviewer Affiliation(s): Duke University School of Medicine, Doctor of Physical Therapy Division
Paper Abstract: Background: Posterior shoulder tightness (PST), defined as limited glenohumeral (GH) horizontal adduction and internal rotation motion, is a common occurrence in overhead athletes, particularly baseball and softball players, as a result of the extreme forces on the GH joint and the high number of throwing repetitions. Despite clinical evidence suggesting the use of joint mobilizations and muscle energy techniques (MET) for treating PST, there currently are no data examining the overall effectiveness of joint mobilizations and MET to determine optimal treatment for posterior shoulder tightness. Purpose: To compare the acute effectiveness of MET and joint mobilizations for reducing posterior shoulder tightness, as measured by passive GH horizontal adduction and internal rotation ROM, among high school baseball and softball players. Study Design: Randomized controlled study. Methods: Forty-two asymptomatic high school baseball and softball players were randomly assigned to one of three groups (14 MET, 14 joint mobilization, 14 control). Glenohumeral passive adduction and internal rotation ROM were measured in all participants in a pre-test post-test fashion. Between testing, the joint mobilization group received one application of GH posterior joint mobilizations. The MET group received one cycle of MET applied to the GH horizontal abductors. The control group received no intervention. Posttests measures were completed immediately following intervention or a similar amount of time resting for the control group and then again 15 minutes later. Results: One-way analyses of covariance showed that the MET group had significantly more horizontal adduction ROM post-treatment compared to the control group (p = 0.04). No significant differences existed between groups in horizontal adduction (p > 0.16) or internal rotation (p>.28) or at the 15-minute posttests (p > 0.70). Conclusion: The results of this study indicate the application of MET to the horizontal abductors provides acute improvements to GH horizontal adduction ROM in high school baseball and softball players, while joint mobilizations provide no improvements. Level of Evidence: 1
NIH Risk of Bias Tool: Quality Assessment of Controlled Intervention Studies
- Was the study described as randomized, a randomized trial, a randomized clinical trial, or an RCT: Yes
- Was the method of randomization adequate (i.e., use of randomly generated assignment)?: Yes
- Was the treatment allocation concealed (so that assignments could not be predicted)?: No
- Were study participants and providers blinded to treatment group assignment?: No
- Were the people assessing the outcomes blinded to the participants’ group assignments?: No
- Were the groups similar at baseline on important characteristics that could affect outcomes (e.g., demographics, risk factors, co-morbid conditions)?: Yes
- Was the overall drop-out rate from the study at endpoint 20% or lower of the number allocated to treatment?: Yes
- Was the differential drop-out rate (between treatment groups) at endpoint 15 percentage points or lower?: Yes
- Was there high adherence to the intervention protocols for each treatment group?: Yes
- Were other interventions avoided or similar in the groups (e.g., similar background treatments)?: Cannot Determine, Not Reported, or Not Applicable
- Were outcomes assessed using valid and reliable measures, implemented consistently across all study participants?: Yes
- Did the authors report that the sample size was sufficiently large to be able to detect a difference in the main outcome between groups with at least 80% power?: No
- Were outcomes reported or subgroups analyzed prespecified (i.e., identified before analyses were conducted)?: Yes
- Were all randomized participants analyzed in the group to which they were originally assigned, i.e., did they use an intention-to-treat analysis?: Yes
Key Finding #1: In asymptomatic high school baseball and softball players, a single application of muscle energy techniques (MET) on the shoulder horizontal abductors produced significant increases in horizontal adduction ROM.
Key Finding #2: The effects of the MET treatment were acute/transient, with the improvements in glenohumeral ROM and posterior shoulder tightness (PST) lasting fewer than 15 minutes. However, this study suggests that athletes may see more prolonged results when performing MET immediately prior to participating in sport activity.
Key Finding #3: Utilizing MET on the horizontal abductors may assist in treating adolescent baseball and softball players with PST due to muscular limitations (versus capsular limitations).
Reviewer Paper Summary: This randomized controlled trial compared the effectiveness between joint mobilizations versus muscle energy techniques (MET) for treating posterior shoulder tightness (PST) in youth baseball and softball players. Effectiveness was measured by analyzing the degree of change between pretest and post-test passive glenohumeral (GH) adduction and internal rotation across 3 groups: the joint mobilization, MET, and control groups. The intervention in the joint mobilization group (n=14) consisted of fifteen, one-second, grade III posterior glenohumeral mobilizations with a one-second rest period between oscillations (total treatment time: 30 seconds). The MET group’s intervention (n=14) involved four application cycles of the following: a three-second passive stretch of the shoulder horizontal abductors followed by a 5-second period of active horizontal abduction into manual resistance at 25% of their maximal capacity. The control group (n=14) remained in a supine position for 60 seconds between the pretest and post-test ROM measurements. Compared to the control group, the single application of MET on the shoulder horizontal abductors produced significant, transient increases in horizontal adduction ROM in asymptomatic high school baseball and softball players. There were no significant differences between joint mobilizations and MET, or joint mobilizations and the control group. The authors therefore suggest that MET may be beneficial in assisting the prevention and treatment of shoulder injuries associated with PST. Future research is recommended to study how to achieve longer-lasting results of MET.
Reviewer Clinical Interpretation of this paper: This study shows that utilizing MET significantly improves shoulder horizontal adduction ROM compared to joint mobilizations in youth baseball and softball athletes with PST. However, the paper states that these changes are transient and do not last longer than 15 minutes. Considering the acuity of these changes, it may be helpful to couple shoulder horizontal abduction MET with immediate therapeutic exercise in a PT treatment session for a patient with PST. Following MET immediately with therapeutic PT exercises may allow the athlete to work more optimally in the newly acquired shoulder ranges of motion, and therefore improve PST outcomes. Implementing a combined approach of MET + therapeutic exercise to prevent or treat PST may lead to more effective PST treatment outcomes, compared to using exercise alone, MET alone, or using joint mobilization. This may be useful for clinicians to consider when creating a plan of care for youth baseball and softball players with posterior shoulder tightness.
