Three-dimensional kinematic analysis of upper limb movements between individuals with and without subacromial...

Subacromial shoulder pain (SSP) accounts for 44-65% of all cases of shoulder pain. Kinematic alterations in the upper limbs have been observed in individuals with SSP, although there is no consensus on such alterations in the literature. Therefore, the present study aimed to compare the three-dimensional kinematics of the scapula, trunk, and arm during shoulder flexion-extension and abduction-adduction movements in individuals with SSP and a control group using statistical parametric mapping (SPM). We evaluated 117 participants [61 with SSP and 56 in the control group (CG)]. The three-dimensional kinematic analysis was performed starting from arm extension/adduction (0%), moving to flexion/abduction, and ending returning to extension/adduction, respectively (100%) in both groups. SSP group flexed more their trunk (0-100%, p < 0.001) and rotated scapula internally (0-20%, p < 0.001 and 75-100%, p < 0.001); rotated upwards (17-32%, p < 0.005 and 58-87%, p < 0.003) and posteriorly tilted (28-79%,p < 0.001 and 81-95%,p < 0.006) less than CG group during arm abduction-adduction. Through arm flexion-extension, the SSP group flexed (38-82% p < 0.009) less their trunk, rotated upwards (5-10% p = 0.021) less their scapula, and posteriorly tilted scapula (0-100% p < 0.001) more than CG. Combining conventional variables used to describe motion in individuals with SSP, such as minimum and maximum values, range of motion, and results provided by SPM can furnish a detailed description of the compensations and limitations of the patient, enabling a better understanding of the function of the scapular girdle as well as improvements in the evaluation process and clinical decision making.