Transmissão de força miofascial entre grande dorsal e glúteo máximo contralateral entre indivíduos com e sem lombalgia crônica

Abstract

The thoracolumbar fascia (TLF) plays an important role in lumbar stabilization and is considered a path of transmitting myofascial force. The superficial layer of this fascia connects to the latissimus dorsi (LD) and gluteus maximus (GM) muscles, enabling the transmission of oblique force between the trunk and lower limbs. Chronic low back pain can modify the mechanical properties of the TLF, which can reduce the efficiency of the myofascial force transmission. The objective of this study was to investigate whether there is a difference in the myofascial force transmission between LD and contralateral GM between individuals with and without chronic low back pain. Forty-eight individuals divided into a low back pain group and a control group participated in the study. Lumbar stiffness variables were evaluated, using a non-invasive digital myotonometer, and passive hip properties (resting position, torque and hip stiffness) were evaluated using an isokinetic dynamometer in two test conditions: relaxed LD and contracted LD. Mixed analysis of variance was used to evaluate the main and interaction effects for the variables of interest. In the presence of an interaction effect, pre-planned contrasts were used to investigate the direction of the interactions. LD contraction increased lumbar stiffness in both groups (p < 0.001), but there was a change in the resting position towards a more lateral rotation of the hip and an increase in passive torque only in the control group (p < 0.001). Furthermore, LD contraction increased passive hip stiffness in both groups, with the hip in the chronic low back pain group already showing greater stiffness than the control group, even in the relaxed LD condition. The present study identified that the myofascial force transmission between LD and contralateral GM via FTL is reduced in individuals with chronic low back pain.