Gender effect on the scapular 3D posture and kinematic in healthy subjects

Abstract

Populations considered for shoulder analysis are often composed of various ratios of men and women. It is consequently hypothesized that gender has no significant effect on the joint kinematic. However, the literature reports, for the shoulder, differences in the range of motion between genders. The specific influence of gender on the scapulo-thoracic kinematics has not been studied yet. The dominant shoulder of two populations of men and women composed of 11 subjects each were evaluated in three dimensions for three distinct motions: flexion in the sagittal plane, abduction in the frontal plane and gleno-humeral internal/external rotation with the arm abducted at 90°. Posture, kinematics and range of motion were studied separately. For flexion and abduction and with regard to the scapular kinematic, external rotation was significantly larger for women than men. The differences were of at least 5° at 120° of humeral elevation. Upward rotations were identical. Women also showed larger average active humero-thoracic range of motion. The mean differences were of 13°, 7°, 12° and 5° for abduction, flexion, internal rotation and external rotation, respectively. No difference was observed between the scapular resting positions of both populations. The observed differences concerning both the scapular and humeral patterns would indicate that the shoulder behaviour of men and women should not be expected to be similar.

Analysis of scapular kinematics in three planes of shoulder elevation: A comparison between men and women

“…In the present study, a consistent, lowspeed task was used. In contrast, the participants in the investigation by Schwartz et al 15) performed a given task at their own speed which, although low, was unknown, a factor which may have affected scapular kinematics. There were also differences in the data processing methodology.…”

“…Passive elements (tightness of the shoulder capsule and coracohumeral and glenohumeral ligaments) limit the motion of the glenohumeral joint 15) . The scapula and humerus are stabilized by muscle activation.…”

“…A difference has been shown between healthy men and women in shoulder muscle activation, with men exhibiting superior muscle activation in the main force direction 21) . It is suggested that weaker muscle strength in women than in men may result in greater joint laxity 15,22) . Generalized joint hyper-71 JPFSM : Gender difference in scapular kinematics during shoulder elevation The daggers indicate significant gender differences: †, P < 0.05; † †, P < 0.01.…”

“…However, it has often been assumed when comparing asymptomatic and symptomatic subjects that there is no gender difference 6,12,13) . Recent reports, though, suggest that gender may influence scapular kinematics 14) , and there have been a few studies exploring gender differences [14][15][16] .…”

“…Studies indicating a gender difference in scapular kinematics 15,16) have demonstrated that external rotation of the scapula was significantly greater in women than in men for flexion and abduction at 120°, with the mean differences being 13° for flexion and 7° for abduction. However, these authors investigated only two planes of elevation, i.e., flexion and abduction, and did not assess scapular plane elevation.…”