title: Hand dominance during constant force isometric contractions: evidence of different cortical drive commands.
abstract: The purpose of this study was to investigate force variability and sensoriomotor strategies of dominant and nondominant hands of right and left-handed subjects during a submaximal isometric force production task. Twelve right-handed adults (9 men and 3 women; 23 ± 3 year) and twelve left-handed adults (4 men and 8 women; 24 ± 3 year) performed an isometric constant force contraction sustained at 30 and 50% of maximal force for 10 s. Surface EMG signals were obtained from forearm flexors and extensors. Force signals were analyzed in the time (CV of force) and frequency (0-10 Hz) domain. The neural activation of the involved muscles was investigated from the EMG structure using the cross-wavelet spectra of the interference EMG signals of six different frequency bands of the EMG signals were quantified (5-13, 13-30, 30-60, 60-100, 100-150 and 150-200 Hz). The major findings were: (1) dominant and nondominant hands of right- and left-handed subjects exhibited similar CV of force; (2) the power spectrum of force is influenced by handedness, with greater 1-3 Hz oscillations for left-handed subjects when compared to right-handed subjects; (3) right-handed subjects have greater 30-60 Hz neuromuscular activation when compared to left-handed subjects. Our results indicate that right-handed individuals may rely preferentially in visual feedback to carry out a task with visual and proprioceptive feedback because of the left hemisphere specialization on the visuomotor control.
authors.affiliation: Department of Biological Sciences, Universidade Estadual do Sudoeste da Bahia, Jequié, BA, Brazil.
authors.forename: Rafael
authors.initials: R
authors.lastname: Pereira
authors.forename: Ivna Vidal
authors.initials: IV
authors.lastname: Freire
authors.forename: Cláudia Virgínia Galindo
authors.initials: CV
authors.lastname: Cavalcanti
authors.forename: Carla Patrícia Novais
authors.initials: CP
authors.lastname: Luz
authors.forename: Osmar Pinto
authors.initials: OP
authors.lastname: Neto
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D002540:Cerebral Cortex / Q000502:physiology*; D054022:Cerebrum / Q000502:physiology; D004576:Electromyography; D056228:Feedback, Sensory; D005260:Female; D007839:Functional Laterality; D006225:Hand / Q000294:innervation*; D018737:Hand Strength; D006801:Humans; D007537:Isometric Contraction; D008297:Male; D009043:Motor Activity; D018482:Muscle, Skeletal / Q000294:innervation*; D009434:Neural Pathways / Q000502:physiology; D010775:Photic Stimulation; D011434:Proprioception; D013997:Time Factors; D055815:Young Adult