ECCENTRIC AND CONCENTRIC STRENGTH OF THE SHOULDER AND ARM MUSCULATUREIN COLLEGIATE BASEBALL PITCHERS

Many pitching injuries occur during deceleration of the upper extremit y when the muscles of the shoulder and arm are acting eccentrically. P ublished information regarding eccentric muscular strength in baseball pitchers is nonexistent. The purpose of this study was to assess bila teral isokinetic eccentric and concentric muscular strength of the sho ulder's external and internal rotator muscles and the elbow's flexor a nd extensor muscles in a group of collegiate baseball pitchers (N = 25 ). Isokinetic strength was assessed at 1.6, 3.7, and 5.2 rad/sec. Our findings indicate that the internal rotator muscles were always strong er than the external rotator muscles and that the concentric and eccen tric external-to-internal strength ratios ranged from 62% to 81%. The eccentric strength of the shoulder rotator muscles averaged 114% that of concentric strength. The concentric and eccentric elbow extension-t o-flexion strength ratios ranged from 71% to 110%; eccentric strength averaged 33% higher than concentric strength. No differences were note d between dominant and nondominant limbs for any of the strength measu res or ratios. Clinically, the findings of this study can serve as a r eference during the evaluation, rehabilitation, and conditioning of th rowing athletes.