Dependence of grip strength on shoulder position and its implications for ergonomics practice

Abstract

Grip strength (GS) variability due to positional changes in the upper extremity joints is of importance while designing workstations and work methods. This study was conducted to analyze the GS variations due to positional changes at shoulder joint when some important variables were under control. The GSs of dominant and nondominant hands were measured in eight shoulder (0 degrees, 45 degrees, 90 degrees, and 135 degrees of flexion and abduction) and standard test positions (STP). One hundred and thirteen subjects 20-30years old completed the study. At the dominant side, no significant difference was observed in the pairwise comparisons between STP and the others. Maximum and minimum GSs were obtained in 0 degrees abduction and 45 degrees flexion and abduction, respectively. At the nondominant side, GSs were significantly lower (p<0.001) in the corresponding test positions and demonstrated more variability. The findings of this study can contribute to the available knowledge to guide occupational ergonomists in their practices.