Análise da cinemática tridimensional e sinergia muscular de mulheres com dor femoropatelar

Abstract

Introduction: Patellofemoral pain (PFP) has a multifactorial etiology and among the factors associated with PFP, the biomechanical are the most discussed in the literature. Kinematics changes in trunk, pelvis and lower limbs are normally associated with PFP patients, but not all changes appear in all patients and in all assessed tasks. Identify which task that most differentiates the subjects with and without PFP could help to make clinical decision regarding assessment of these patients and then guide the identification of possible causes of kinematic changes, since muscle strength appears to be unrelated with kinematic. We know that muscle activities depend on the neural control that activates the musculature by muscle synergies and the motor control could be influenced by pain, to investigate if there are changes in neuromuscular organization could contribute to a better understanding of PFP and help to improve the treatment and assessment strategies to PFP patients. Objective: 1. Identify which functional tasks differentiates the three-dimensional kinematic of women with and without PFP. 2. Analyze the muscle synergies of women with PFP and correlate with the kinematic of the trunk, pelvis and lower limbs during the lateral step down (LSD). Methods: 1. Cross-sectional study that evaluated 35 women with PFP and 35 asymptomatic women during the execution of seven functional tasks. Three-dimensional kinematic data were analyzed through the Movement Deviation Profile (MDP). To identify which task presented the most differences between the groups, the Z-score of the mean MDP was calculated. 2. Cross-sectional study with 15 women with PFP and 14 asymptomatic submitted to three-dimensional kinematic and electromyography (EMG) assessment during the LSD. Muscle synergies were extracted from EMG signals using a non-negative matrix factorization algorithm. Kinematics data were analyzed through MDP. The data were compared by independence t test and correlated by Pearson correlation test. Results: 1. For all tasks, the groups presented differences, but according with Z-score the LSD (7.97) and forward step down (7.62) were the tasks that most differentiate the kinematic of the groups. 2. Women with PFP showed no differences in the minimum number of muscle synergies necessary to explain most variability of EMG (VAF) to perform the LSD, but showed higher VAFtotal and VAFmuscle for rectus femoris and vastus medialis compared to asymptomatic women. For PFP, the lower the similarity in the muscle participation in each muscle synergies (W2, W3 e Wmean) compared to control, the higher the differences in trunk, pelvis and lower limbs during the LSD. Conclusion: Step down tests are the tasks that most differentiate the kinematic of women with and without PFP, the LSD was the tasks with the highest sensitivity to detect differences. During the LSD, PFP women showed poor muscle control and coordination, mainly for the rectus femoris and vastus medialis muscles and these findings have correlation with the higher changes kinematics during the task execution.