Laterality, manual strength and precision performance

Right handers are frequent in some particular sports, and this is probably related to a technical and tactical advantage for them (1), but sometimes athletes in typical left-handers’ roles are not strongly left-handed. The aim of this study was to investigate differences in performance by athletes who use their right or left hand consistently in both daily activities and their sport (R=right-handers; L=left-handers) and by athletes who are right-handed in daily activities but left-handed in their sport (I=inconsistent). Methods Laterality assessment through the Edinburgh test(2) and resulting from the hand used in the sport; identification and comparison of manual Maximal Strength (MS), Kinesthetic Strength Differentation (KSD) and Movement Frequency (MF) in R, L, I (R hand vs L hand); identification and comparison of the best and worst hand for each in R, L, I. MS and KSD were measured by dynamometer in different hand-grip trials of maximal strength and 75% MS. MF was measured by counting the maximal comma numbers performed when writing for 30 seconds(3). Subjects Medium-high level athletes (N56; R=22, L=22, I=12), highly trained (hours per week: avg 9.8 – SD 3.04) in open-skill sports: handball (21), basketball (7), volleyball (9), fencing (5), judo (1), hockey (9), table-tennis (2) and squash (2). Results Comparison of right and left hands (Mann-Whitney test): in the MS test, only the R group shows significant differences (p<0,01); in the KSD test only the I group shows significant differences (p<0.05); in the MF test all 3 groups show significant differences (p<0.01). Comparing the 3 groups as regards the best hand (Wilcoxon test), only the KSD test shows significant differences between R (left hand) and I (left hand) (p<0.01). In the L (right hand) and I (right hand) groups, the differences are in the weakest hand (p<0.05). Conclusions In the MS test the best results are achieved with the hand preferred for sports; in the KSD test the opposite is the case for R and L. By contrast, in the MF test the best results are attained by R and L with the sports hand, but by I with the preferred for daily activities. References 1. Grouios et al (2000). Do left-handed competitors have an innate superiority in sports? Percept Mot Skills, V. 90; 1273-1282 2. Oldfield R.C. (1971). The assessment and analysis of handedness: the Edinburgh inventory. Neuropsychologia V. 9, Is 1; 97-113 3. Carbonaro G. et al (1988). La valutazione dello sport nei giovani. Società stampa sportiva, Roma