Postoperative eccentric and concentric isokinetic strength for the shoulder rotators in the scapular and neutral planes.

Abstract

Considerable variability exists for isokinetic testing of the shoulder rotators, leaving the clinician in a quandry concerning the most appropriate method for patient evaluation. The purpose of this study was to evaluate concentric and eccentric rotational strength in the scapular and neutral planes for the surgical and nonsurgical shoulders. Fifteen males consented to be tested during a 90-minute isokinetic session. Both shoulders for each patient were tested concentrically (240 degrees/sec) and eccentrically (120 degrees/sec) in the scapular and neutral planes. Patient positioning was maintained through the use of a goniometer, plumb line, and floor grid system. Following a warmup, five maximal effort reciprocal internal and external rotation concentric and eccentric contractions were evaluated using multiple two-way analyses of variance (shoulder x plane) with repeated measures. Results indicated no statistically significant differences between the surgical or nonsurgical shoulders for either concentric (p = .063-.247) or eccentric (p = .460-.840) modes, regardless of test plane. No statistically significant differences were observed eccentrically between test planes (p = .06-.470), but the scapular plane produced significantly higher (p = .005) peak torques concentrically. Generally, the external rotators were 53.0% (concentrically) and 63.0% (eccentrically) of the internal rotator strength for either shoulder. Clinically, concentric and eccentric testing of the postoperative shoulder patient can occur in either the scapular or the neutral plane. However, the scapular plane may be preferred since it is more functionally relevant and less injurious to the rotator cuff. A full, functional recovery may be expected for the rotator cuff repair patient.