Abstract
The aim of this study was to examine bilateral isometric muscle strength (IMS) in right-handed boys. To determine the association between the magnitudes of right handedness (MRH) and (a) the interside difference indexes of IMS of certain muscle categories, (b) age, and (c) some anthropometric characteristics. This was a cross-sectional study. A convenience sample of 94 right-handed boys between 6 and 10 years of age was investigated. The Edinburgh Handedness Inventory was used to evaluate hand dominance and its magnitude. IMS of eight muscle groups was measured and the interside difference was determined. Five interside difference indexes were calculated for the upper limb, lower limb, hand grip, key pinch, and total side. All interside difference indexes of IMS were less than 5%, in favor of the dominant right side. The majority (86.1%) of our boys scored high to moderate MRH, whereas the minority (13.8%) scored low MRH. The hand grip interside difference index (beta=0.40, P=0.000), the key pinch interside difference index (beta=0.23, P=0.003), age (beta=0.24, P=0.034), and height (beta=0.33, P=0.039) are the best set of predictors of the dominance score and in turn the MRH. The results of this study, carried out on right-handed boys aged 6-10 years, indicated a standard difference in IMS between dominant and nondominant sides of all studied muscle strength categories. Furthermore, it was found that the hand grip interside difference index, the key pinch interside difference index, age, and height could influence the MRH.