A Comparative Study of Left and Right Hand Grip Strength in Different Positions of Shoulder and Elbow

There are numerous daily tasks that require a stronger grip in various positions other than the standardized testing protocol for handgrip strength. Therefore, in the clinical practice it is necessary to understand how deviations from standard position can affect grip strength. This study has investigated the differences in left and right grip strength in different positions of shoulder and elbow combinations.

Grip strength of forty healthy subjects was tested with a hydraulic dynamometer in six testing positions. The tests consisted of three positions, in which the elbow was maintained in full extension combined with varying degrees of shoulder flexion (i.e. 0°, 90° and 180°) and other three positions in which the elbow was maintained at 90° flexion combined with varying degrees of shoulder flexion (i.e. 0°, 90° and 180°).

In right hand, the highest mean grip strength measurement of 38.9 with SD 14.1, when the shoulder was positioned in 180° of flexion with elbow fully extended. Whereas, the lowest mean grip strength measurement of 35.6 with SD 12.0 was recorded in 180° of shoulder flexion with elbow flexed at 90°. In left hand, the highest mean grip strength measurement of 36.4 with SD 11.9 when the shoulder was positioned in 180° of flexion with elbow fully extended. Whereas, the lowest mean grip strength measurement of 33.5 with SD 9.2 was recorded in 180° of shoulder flexion with elbow flexed at 90°. The results of ANOVA, in left hand showed significant difference (p=0.005) in grip strength across all six testing positions and significant difference (p=0.0000) for the total subjects. For right hand findings of ANOVA suggested significant difference (p=0.00092) in grip strength across all six testing positions and significant difference (p=0.0000) for the total subjects. Consequently, the Bonferroni correction for multiple comparisons was done, yielding an experiment-wise alpha level of 0.05. This value indicated statistically significant differences existed in the total sample and among the all positions for both left and right hand. In both left and right hand more significant differences were found in 180° shoulder flexion with elbow flexed at 90° and 180° shoulder flexion with elbow fully extended.

The changes in left and right hand grip strength observed with variations in shoulder and elbow position. Grip strength improved with the increasing flexion angle of shoulder joint. It is vital that when measuring grip strength, one understands how small changes in body position can result in altered grip strengths.