Contribuições complementares das rotações sagitais e axiais das articulações e do pé do membro de apoio para a progressão anterior do corpo na marcha

Abstract

Introduction: In gait the joint rotations (movement and position) of the stance lower limb seem to be complementary to the function of producing and stabilizing the position and progressive anteroposterior displacement of the pelvis. The purpose of this study was to investigate the contributions of the lower limb joints in the sagittal and axial planes to the generation of anteroposterior position and displacement of the pelvis, and whether these contributions are significant. In addition, this study investigated if these contributions are complementary to produce and stabilize the anteroposterior position of the pelvis, within cycle and among different cycles and, if complementary, how and when the complementarities occur. Materials and methods: Eleven healthy young adults participated in the study, who underwent three-dimensional kinematics analysis of the right lower limb during the stance phase of walking, with a self-selected comfortable speed, on an electric treadmill. To calculate the time series of the contributions of the joints to produce the anteroposterior position of the pelvis, a geometric model of linked segments was used, as well as partial derivatives of each joint, in each frame. Friedman and Wilcoxon tests were used to verify if the contribution of each joint was significant. In order to characterize the individual influences of each joint for the anterior displacement of the body, the coefficient of influence (i.e. partial derivative) was first calculated. The displacement of the pelvis generated by each joint, in percentage and in meters, was also calculated. For the complementarity of the joints within a cycle, the coefficient of multiple determination (CMD) was used. The error (root mean square error) was calculated to verify if the position of the pelvis was stabilized between different cycles. In sequence, the existence of complementarities among different cycles was analyzed, considering high negative covariations (r -0.5), frame by frame, between the contribution of one joint and the contributions of the other joints. Results: The contributions that were considered significant were from all joints in the sagittal plane and the ankle in the axial plane. In the same cycle, the joints that contributed to the anteroposterior displacement of the pelvis, in order of greater contribution to lower contribution were: forefoot, ankle (sagittal plane), knee, midfoot joint complex, rearfoot, hip and ankle (axial). The mean coefficient of influence of the joints of the foot together was 1.6 cm/°. The CMD value for the complementarity test within cycle was considered high (0.897 ± 0.095). Intra-step (within cycle) complementarity was demonstrated through the contribution curves together, showing how the joints behave to generate the linear anteroposterior position of the pelvis. There was an inter-subject variation in the complementarity among steps (among cycles), both in the joints that participate, and in the instants of the stance phase in which these functional compensations occur, stabilizing the anteroposterior position of the pelvis. Conclusion: The individual and complementary functional contributions of lower limb joints in gait stance were revealed. This allowed to characterize functional compensations of movement, in the same cycle and in different cycles, which helps to guide future research and clinical reasoning to address these compensations and possibly related dysfunctions.