Comparison of Immediate Effects of Three Types of Static Self-Stretching on Pectoralis Minor Length and Round Shoulder Posture Angle in Young Adult Females
Keywords:Stretching, Pectoralis minor muscle, Round shoulder posture
Round shoulder posture is one of the most common postural disorders. The tightness of pectoralis minor muscle is a factor associated with postural abnormalities. Furthermore, the inflexibility of pectoralis minor muscle may be the main cause of scapular dyskinesis and may lead to shoulder impingement. Stretching of pectoralis minor is one method to increase the muscle length. However, the pectoralis minor muscle stretch has several methods. The study aimed to compare the immediate effects of three static self-stretching methods on pectoralis minor muscle length and round shoulder posture angle. 17 female subjects aged between 18-30 years measured were recruited. Their measured pectoral muscle length and round shoulder posture angle were before stretching the pectoralis minor muscles by themselves. After that, the participants were randomly selected to stretch theirpectoralis minor muscle 1 way per day using 3 methods for 3 consecutive days, which includes active scapular retraction stretching (ASR), unilateral corner stretching (UC) and low load prolong stretching (LLP) methods. Finally, the length of their pectoralis minor muscle and the angle of round shoulders were measured immediately after the stretch. The data obtained were statistically calculated using Paired ttest to compare pectoralis minor length index and round shoulders posture angle between pre- and post-test in all three groups and one way ANOVA to determine the differences between the three methods of stretching muscles using the post - hoc analysis statistics. The result showed that the three static self-stretching methods could increase pectoralis minor muscle length and decrease round shoulder posture angle. However, it was found that LLP method increased the pectoralis minor muscle length and decreased the round shoulders posture angle statically significant greater than UC method and ASP method. (p<0.05) Therefore, the stretching method can be appliedto people with round shoulders posture or people with the tightness of pectoralis minor muscle to increase muscle length, decrease scapular dyskinesis and mayreduce the risk of subacromial impingement.
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