Hand span influences optimal grip span in male and female teenagers.

Purpose: To determine if there is an optimal grip span for determining the maximum handgrip strength in male and female teenagers, and if the optimal grip span was related to hand span. If they are related then the second aim was to derive a mathematic equation relating hand span and optimal grip span.
Methods: One hundred healthy teenage boys (15.1 +/- 1.1 y) and 106 girls (15.4 +/- 1.3 y) were evaluated (age range, 13-18 y). Each hand was randomly tested on 10 occasions using 5 different grip spans, allowing a 1-minute rest between attempts. The hand span was measured from the tip of the thumb to the tip of the small finger with the hand opened as wide as possible.
Results: The results showed that an optimal grip span to determine the maximum handgrip strength was identified for both genders, and the optimal grip span and hand span correlated in both genders.
Conclusions: The results suggest that there is an optimal grip span to which the dynamometer should be adjusted when measuring handgrip strength in teenagers. The optimal grip span was influenced by hand span in both genders. For males the optimal grip span can be derived from the equation y = x/7.2 + 3.1 cm, and for females from the equation y = x/4 + 1.1 cm. where y is the optimal grip span and x is the hand-span. These equations may improve the reliability and accuracy of the results and may guide clinicians and researchers in selecting the optimal grip span on the hand dynamometer when measuring handgrip strength in teenagers.