Tendon Diameter of Rotator Cuff and Strength of the Shoulder External/Internal Rotator Muscles in Elite Thrower

Bang, In Keol; Lee, Jeong Pil; Kim, Young Joo; Kim, Chul; Kim, Gwang Hae; Reu, Hyun Woo; Oh, Jae Keun

Abstract

OBJECTIVE
To know the characteristics of muscle strength and tendon diameter of rotator cuff in the elite thrower and correlation between both parameters. METHOD: Twenty-four elite throwers (male 16, female 8) without pain and injury were included. Dominant hand was right side in all subjects. Thickness and width of rotator cuff except teres minor were measured with ultrasonography. Concentric strengths of shoulder internal (IR) and external rotators (ER) were measured with isokinetic device.
RESULTS
There was no difference between dominant and nondominant shoulder in tendon diameter except that thickness and width of dominant infraspinatus were greater than nondominant. ER/IR peak torque ratio was about 1.0 in both sides. There were significant correlations between subscapularis thickness and IR strength, infraspinatus width and ER strength, supraspinatus thickness and ER strength, supraspinatus width and ER strength, infraspinatus thickness and IR strength, infraspinatus width and IR strength in nondominant side, and subscapularis thickness and ER strength in dominant side.
CONCLUSION
It is possible that external rotation peak torque is increased in elite thrower. Muscle strength could not be expected by tendon diameter except nondomiant subscapular thickness and infraspinatus width. This study will be the basis of the next study about elite thrower.