A single session of a muscle energy technique (MET) applied to the glenohumeral joint (GHJ) horizontal abductors of asymptomatic collegiate baseball players made a significant improvement in GHJ horizontal adduction range of motion (ROM) immediately after the intervention, a recent research article reports.

The study, “A Randomized Controlled Trial of the Immediate Effects of Muscle Energy Techniques on Posterior Shoulder Tightness,” involved 61 baseball players from three NCAA Division I schools. The players, who volunteered to participate in the study, were asymptomatic. A history of previous surgery or any dominant-side upper extremity injury in the previous six months were exclusion criteria.

Subjects in the study were randomly assigned to one of three groups: MET for the GHJ horizontal abductors, MET for the GHJ external rotators and a control group. Each participant attended one session, which began with a measurement of dominant-arm GHJ external and internal rotation ROM, as well as GHJ horizontal adduction ROM.

Following the baseline ROM measurements, a single session of MET was applied to either the GHJ horizontal abductors or the GHJ external rotators, depending on the player’s group assignment. The post-intervention measurements of ROM were taken immediately after this application of MET, which was about two minutes after the baseline measurements were obtained. Those subjects in the control group simply rested on the examination table for the two minutes between ROM measurements.

The researchers in this study describe MET as “a manual therapy intervention that can be used to stretch or lengthen muscles and fascia lacking in flexibility.” They explain that “MET requires the patient to create a force by activating targeted musculotendinous unit against a precisely directed counterforce applied by the clinician, followed by relaxation and a passive stretch applied by the clinician.”

For this study, the subjects were asked to perform a five-second isometric contraction at about 25-percent maximal effort, against the practitioner’s opposing force. After this contraction, the practitioner applied a 30-second active assisted stretch. This was repeated a total of three times.

Results of the research show that subjects in the group that received MET for the GHJ horizontal abductors had a significantly greater increase in GHJ horizontal adduction ROM following the intervention, as compared to the group that received MET for the external rotators, as well as the control group.

“The use of muscle energy technique for the glenohumeral horizontal abductors may assist in gaining posterior shoulder flexibility in baseball players and individuals prone to tightness of the posterior shoulder structures,” the study’s authors conclude.

Authors: Stephanie D. Moore, Kevin G. Laudner, Todd A. McLoda and Michael A. Shaffer.

Sources: School of Kinesiology and Recreation, Illinois State University, Normal, Illinois, and University of Iowa Sports Medicine, Iowa City, Iowa. Originally published in the Journal of Orthopaedic & Sports Physical Therapy (2011) 41.

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