A literature review of the effect of handedness on isometric grip strength differences of the left and right hands.

When estimating preinjury grip strengthfor compensation and rehabilitation purposes, two methods have been identified in the literature: (a) comparison with the unaffected hand and (b) reference to grip strength normative data. The literature is divided about whether a significant difference exists between the grip strengths of a person's two healthy hands. Some researchers argue that handedness affects the grip strength ratio. According to these authors, there is considerable variation in the definition of handedness, its effect on grip strength ratios, and the methods of assessing handedness as it relates to grip strength. The complexity of defining and accurately evaluating handedness is discussed in this literature review. Inappropriateness of the current use of self-report questionnaires for determining handedness for grip strength purposes is highlighted. The impact of the effect of handedness on grip strength ratios cannot be clarified until a consistent definition and evaluation method for assessing handedness is developed. This handedness definition then needs to be applied to appropriately designed hand grip strength studies.