Comparing Dominant and Non-Dominant Hand Performance With Force Changes In a Two Hand Equilibrium Task: A Challenge to Dominant Hand Theories

Objective: Although most studies believe that the dominant hand performs better than the non-dominant hand in performing various tasks, there is still the challenge among researchers as to why the non-dominant hand performs better than the dominant hand in certain situations and tasks. The aim of this study was to compare dominant and non-dominant hand performance with force changes in a two-handed balance task. Methods: The samples of this study consisted of 30 male and female subjects with age (y) Mean±SD of 28±6.5. This research was conducted in Shiraz Health Center. In this study, a Huber device was used to measure hand function. Results: The results of the independent t-test showed that when the force on the handle sensor was the same in both hands, the performance of the dominant and non-dominant hand did not differ significantly (P>0.05). However, the dominant hand performed better when the dominant hand-applied more force and the non-dominant hand performed better than the dominant hand when the non-dominant hand applied more force to the handles (P<0.05). Conclusion: The results of this study showed that the performance of the superior hand is not always better than the non-superior hand and the performance of both hands depends on the type of task, synthetic factors (force), and the amount of attention to each hand. These results support the theory of dynamic systems and the specialized hemisphere model in hand control

Synergy patterns of brain activity during learning of the dart throwing skill with the dominant and non-dominant hand

The mechanism and neural origin of the differences between the two hands in motor control and learning are still unknown. The aim of the present research is to examine the changes in synergy patterns in different brain regions while learning the dart throwing skill with the dominant and non-dominant hand. The sample population consisted of 10 students aged 23±2.5 divided into two groups of dominant and non-dominant hand. To record brain activities, a 32-channel wireless Electro-encephalography (EEG) system was used. Data were recorded through three stages of pre-test (pre-training), acquisition (after 4 weeks of training) and retention (after one week of non-training). EEG signals were analysed in alpha, beta and gamma bands. EEG analysis showed that the synergy patterns during acquisition and retention stages were significantly similar to each other and largely different from the pre-training stage in all three bands. Increasing activity levels of the contralateral cortical areas and formation of a different activity pattern after learning in the two groups, were other results obtained. Learning a new motor skill requires relatively lasting changes in the brain map and synergy patterns of brain activities are different for motor learning when the dominant or non-dominant hand is used. Keywords: Brain activity; Dart throwing; Motor learning; Motor skills; Synergy pattern