Effects of a 12-week hip abduction exercise program on the electromyographic activity of hip and knee muscles of women with patellofemoral pain: A pilot study

Abstract

Aims: The purpose of our study was to compare the hip and knee muscle activity before and after a hip abduction exercise program in women with patellofemoral pain (PFP). Methods: Eleven women with PFP were included in our pre/post design study. Participants were assessed before and after 12-week hip abduction exercise program. All participants performed 6 stair climbing repetitions, 3 sets of rope jumps over 30 s and 5 sets of 8 squats to standardize the physical activity level before data collection. We recorded the electromyographic activity from gluteus medius, vastus medialis (VM) and vastus lateralis (VL) for double-legged squat with and without isometric hip abduction. Additionally, participants were asked to perform a step-down test to assess objective function (maximum number of repetitions over 30 s) and completed a clinical evaluation. Results: Longer duration of VM (Mean difference [95% CI]) = -0.97 [-1.48; -0.46], ES [effect size] = 0.66) and VL (-0.81 [-1.35; -0.27], ES = 0.54) were found after the hip abduction exercise program only for free squat. The participants also performed higher number of step-down repetitions (-3.54 [-5.84; -1.25], ES = 1.03) after the hip abduction exercise program and showed improvement in pain reports. Conclusion: A 12-week hip abduction exercise program changed the quadriceps muscle activation pattern and improved pain and objective function of women with PFP. The exercises promoted a longer VM and VL activation duration. Additionally, they promoted a clinical improvement in the patients with PFP.

Relationship of anteversion of the femoral neck with patellofemoral pain syndrome in young women not practicing regular physical activity

“…Patellofemoral pain syndrome (PFPS) is defined by the presence of anterior knee (retropatellar) pain, related to the increase of contact pressure (stress) in the patellofemoral joint, being the most common athlete's knee problem, especially in runners. PFPS etiology is not well established, nevertheless, it's related to multifactorial causes like direct trauma or any activity that may cause patellofemoral joint compression, like long periods of sitting, squatting, going up and down stairs, which makes it harder to diagnose [1][2][3] .…”

“…PFPS also makes up 3% of all diseases that attack the knee 1,4 . PFPS risk factors include quadriceps muscle weakness and biomechanical misalignments in the Q angle, tibiofemoral angle, external static rotation of the knee, tibial lateral torsion and hyperpronation of the foot, which affect the distribution of forces acting on the knee joint, since their adequate alignment is necessary for a harmonious functioning between the hip and knee joints [1][2][3]5 . The proximal portion of the femur is influenced by both the frontal and axial plane.…”