O efeito da lateralidade sobre o esforço percebido, controle postural e recrutamento muscular nas variações do exercício quadrúpede

Abstract

Introduction: Laterality is a manifestation of the cerebral hemispheres that expresses the preference of one of the limbs to perform motor tasks. The literature lacks information on the effects of handedness in static activities involving closed kinetic chain (CKC) postural control, such as quadruped exercises (QE), when one of the upper limbs (UL) is part of the base of support (BS). From a clinical standpoint, understanding possible differences related to the laterality of the UL in the BS during QE in healthy individuals can be useful in understanding motor patterns and prescribing these exercises. Objective: To investigate how handedness affects muscle recruitment patterns, postural control, and perceived effort in QE. Methods: Thirty female volunteers performed three QE (classic bird-dog - CB; reverse bird-dog - RB; homolateral bird-dog - HB). Surface electromyography (sEMG) was bilaterally recorded in the transversus abdominis (TA), multifidus (MD), longissimus thoracis (LT), and iliocostalis (IC) muscles. Stabilometry was obtained by recording the center of pressure (CoP) of the hand on a pressure mat, and perceived effort was measured using the Borg scale. Results: The overall mean muscle activation did not show significant differences between the QE and palm BS. In the intramuscular comparison, the TA muscle was the only one to show a significant difference, with the preferred side being more recruited (p < 0.05). Regarding muscle activation between palm BS, the contralateral TA, LT, and IC muscles showed higher activation in both CB and RB conditions (p < 0.05), but not in HB. Unlike the others, the MD muscle demonstrated the highest activations on the ipsilateral side to the palm BS in all QE (p < 0.05). Regarding the elliptical area of the CoP, the HB condition presented higher values regardless of the palm BS used compared to the other conditions (p < 0.05), however, only CB showed a significant difference between palm BS, indicating a larger elliptical area on the non-preferred side (p < 0.05). As for perceived effort, the HB condition proved to be the most challenging QE (p < 0.05), but no significant differences were observed between palm BS in each QE. Conclusion: Handedness seems to have little influence on QE for the analyzed outcomes, as despite the preferred hand enjoying a greater motor repertoire, which consequently allowed for greater stability in exercises with contralateral BS, it did not result in different degrees of muscle activation and perceived effort, emphasizing caution when interpreting results without considering intervening factors.