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.

Concentric and eccentric torque variations of the quadriceps femoris in patellofemoral pain syndrome.

The purpose of this study was to investigate the extent of torque reduction in the quadriceps femoris in subjects complaining of patellofemoral pain syndrome compared to subjects with sound knees. Fifty-five patients (21 women and 34 men) and 30 healthy subjects (15 women and 15 men) took part in this study. Using the KINCOM isokinetic dynamometer, quadriceps torque was assessed at 30°/s, 60°/s, and 120°/s, both in the concentric and eccentric modes. Findings demonstrated a significant (P < 0·01) reduction of between 30% and 40% in the patients when compared with the control group. This reduction was not speed or mode-specific. Men were stronger than women by a margin of 22% and 14% for the concentric and eccentric modes in the control group. Parallel figures for the patellofemoral pain syndrome group were 25% and 17%. Good to high correlations were found between peak and average torque in both groups. There were no significant differences between the muscles referring to the dominant versus the non-dominant legs of the control group.

Thigh muscle activity and anterior cruciate ligament insufficiency.

The purpose of this study was to examine the dynamic relationship between the quadriceps femoris and hamstrings in anterior cruciate ligament (ACL) insufficiency. Thirty-five young active patients with an untreated complete tear of the ACL took part in the study. Using a KINCOM isokinetic dynamometer, the dynamic capacity of each muscle group at 30° in concentric and eccentric exertion in both the deficient and sound knee was measured. Findings demonstrated a significant reduction (P<0.05) in the torque produced by the deficient-side quadriceps compared to the sound side but no significant variations in the hamstring torque. Discussion of the findings considers a possible involvement of neurophysiological inhibition of the quadriceps as a cause for the observed weakness.