Hip eccentric torque, gluteal muscles activation and trunk and lower limb kinematics during single-leg squat and functional performance in individuals with isolated patellofemoral osteoarthritis

Abstract

Previous studies have observed that with patellofemoral pain (PFP), there is a decrease in the abduction, extension and external rotation strength of the hip, decrease gluteal muscles activation as well as an increase in the ipsilateral inclination of the trunk, contralateral pelvic drop, hip adduction and knee abduction during activities with unilateral support of body weight. Considering that, a significant number of patients with patellofemoral osteoarthritis (PFOA) have a history of PFP, it is speculated that the mechanical causes of PFP and OAPF may be similar. Therefore, the objective of this study will be to compare the eccentric strength of the hip muscles, gluteal muscles activation and the tridimensional kinematics of the trunk, pelvis, hip and knee during the single leg squat and the functional capacity between subjects with and without PFOA isolated. Eccentric torque of the hip abductors, hip extensors and hip external rotators will be evaluated by isokinetic dynamometer Biodex Multi-Joint System 3. The kinematic analysis during the single-leg squat, will be evaluated using Vicon system, by means of six cameras (Bonita 10) and in this task will be evaluated the electromyographic of surface (EMG) signal of the gluteus medius and gluteus maximus; the 30s chair stand test, 40m fast-paced walk test, and the stair climb test will be applied to assess functional capacity; the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and will be applied last. The t-test Student for independent samples or the Mann-Whitney test will be used to compare the maximal eccentric strength of the hip and EMG data between the groups. For the kinematic variables will be used the two-way ANOVA with post hoc of Bonferroni. Finally, the Pearson or Spearman correlation coefficient will realize the analysis of the relationship between maximal strength of the hip, EMG signal of hip muscles and trunk and lower limb kinematics, WOMAC domains and performance in functional tests. The significance level for all tests will be 5% (p d 0.05). (AU)