Date of Award
Master of Science (MS)
School of Kinesiology and Recreation
Noelle M. Selkow
Context: Overhead sports are at an increased risk of shoulder injury, particularly when scapular posture is restricted. Pectoralis minor length has been linked to scapular malpositioning and forward shoulder posture. Upper extremity blood flow has also been linked to shortened pectoralis minor length, which could lead to thoracic neurovascular occlusion. Swimmers specifically may be at an increased risk for shoulder injury if the pectoralis minor is shortened. Stretching of the pectoralis minor has been suggested as a treatment to correct shortening of the muscle, however research examining muscle energy technique (MET) applied to the pectoralis minor is limited. Objective: To determine the effect of MET on forward shoulder posture, pectoralis minor length, and upper extremity blood flow in asymptomatic collegiate swimmers. Design: A controlled laboratory study with repeated measures. Setting: Swimming facilities or athletic training room of respective participants. Participants: Thirty-six NCAA Division I female collegiate swimmers participated. Participants were placed into one of two groups: Treatment group (n= 22): age= 19.7 Â± 1.2yrs, height= 170.2 Â± 5.0cm, mass= 67.8 Â± 6.7kg and Control group (n= 14): age= 19.6 Â± 1.3yrs, height= 169.0 Â± 4.6cm, mass= 67.2Â± 5.8kg). Interventions: The MET group received two treatments of MET for forward shoulder posture each week, separated by 48 hours, for a total of 6 weeks (12 total treatments). No treatment was applied to the control group. Main Outcome Measures: Baseline, week 3, and week 6 forward shoulder posture, pectoralis minor length, and upper extremity blood flow were assessed. Forward shoulder posture was measured using the double square technique. Pectoralis minor length was measured using calipers. Blood flow was measured using non-invasive diagnostic ultrasound. Separate repeated measures ANCOVAs were completed for each dependent variable. Alpha was set a priori at α≤.004 using a Bonferroni correction. Results: Significance was found in the resting condition of the dominant arm only, where blood flow was greater in the control group compared to the MET group at week 6 (p=.001). There were no other significant findings for the other blood flow positions (p>.01) or at any time point for forward shoulder posture (p>.44) and pectoralis minor length (p>.22). Conclusions: MET had no effect on forward shoulder posture or pectoralis minor length when compared to the control group. However, the blood flow of the dominant arm while in the resting position was higher for the control group when compared to the MET group at week 6. The results of this study are in contrast to those found in previous studies; therefore the benefits of MET for the shoulder should continue to be investigated. Word Count: 425
Gross, Elizabeth, "The Effect of Muscle Energy Technique on Forward Shoulder Posture, Pectoralis Minor Length, and Upper Extremity Blood Flow in Collegiate Female Swimmers" (2015). Theses and Dissertations. 325.