Isokinetic strength relationships in shoulder muscles.

The purpose of this study was to extend and refine former findings which related to strength characteristics of the major muscle groups operating on the glenohumeral joint. Based on preliminary isokinetic evaluation of five women and five men, which indicated that overall dominance was not associated with significantly stronger muscles, the dominant shoulders of 30 normal non-athletic subjects, 15 women and 15 men, were tested concentrically and eccentrically, at 60, 120 and 180 degrees /s. The descending order of muscle strength at both contraction modes and for both genders was: extensors, adductors, flexors, abductors, internal rotators and external rotators. Inter-muscle groups' strength correlation coefficients have indicated significant, moderate-fairly strong, relationships in men but not in women. The implications of these findings in terms of testing and shoulder muscle conditioning are discussed. RELEVANCE:--Analysis and interpretation of shoulder muscle dysfunction, and implementation of conditioning protocols, require the availability of normative values pertaining to the common modes of contraction and relative to an acceptable and velocity setup. This study provides a representative data base of normal subjects which may serve for these purposes.