Controle postural em mulheres destras durante tarefas de alcance e preensão

Abstract

Laterality is a multidimensional phenomenon, manifesting in terms of lateral preferences and performance asymmetries. The dominance of rightside preference is observed in approximately 90% of various populations. The literature provides evidence that differences in movement control between the right and left sides are due to neural specificities related to each hemisphere. The coordination between posture and movement is essential for human functionality, and measuring potential differences in the displacement of the pressure center under different task conditions of reaching and grasping for both upper limbs can offer valuable insights into the theme of postural control and laterality. Objective: To investigate the effect of a reaching and grasping task under different conditions on the control of orthostatic posture. Methods: A cross-sectional study was conducted with 30 female participants (24±3 years, mean ±SD), who performed a reaching and grasping task under different conditions using the right and left upper limbs. The evaluation of variables related to the displacement of the pressure center (elliptical area, mean velocity, medial-lateral excursion, and anterior-posterior excursion) was performed using a force platform, aiming to make comparisons both between the upper limbs and between the task conditions. Results: Concerning the disparities between the right and left limbs, a uniform increase in the values of the Lateral Symmetry Index (LSI) was observed for all variables related to the displacement of the pressure center, in the middle-to-left condition when performed with the right hand, while lower values were recorded in the middle-to-right condition when executed with the left hand. Furthermore, the forward-reaching condition promoted increases in the medial-lateral excursion, indicative of greater displacement when the right hand was used. Conclusion: A dynamic manual task causes almost the same postural oscillation when performed with the left and right upper limbs. Our proposition suggests that the disparities observed in the variables of the pressure center displacement between the task conditions are associated with the direction of the movement, particularly when it crosses the body's midline.