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.

As medidas de confiabilidade das análises da arquitetura muscular pela ultrasonografia são importantes referências para estudos aplicados de mecânica muscular. O objetivo deste estudo foi determinar a confiabilidade das medidas de espessura muscular (EM), ângulo de penação (AP) e comprimento da fibra (CF) do músculo Vasto Lateral (VL). As imagens de ultrassom foram obtidas em um grupo (N=14; 22 ± 1,75 anos) em duas visitas (sessenta medidas por indivíduo). Foi calculado o coeficiente de correlação intraclasse (CCI), coeficiente de variação (CV) e erro típico da medida (ETM). Os resultados demonstram alta confiabilidade: CCI AP (0,83 a 0,99), EM (0,96 a 0,99) e CF (0,80 a 0,99); CV AP (3,68 a 6,34%), EM (3,12 a 3,84%) e CF (3,98 a 6,33%) e ETM AP (0,18 a 0,59º); EM (0,014 a 0,15mm) e CF (0,07 a 1,47mm). Essas medidas devem ser consideradas em estudos que analisam o impacto na arquitetura muscular em programas de condicionamento do Vasto Lateral.

Reliability of the measurements of the muscle architecture variables by ultrasound are important references for applied studies of muscle mechanics. The aim this study was to analyze the reliability of measurements of Vastus Lateralis (VL) muscle thickness (MT), pennation angle (PA) and fiber length (FL). Ultrasound images were obtained in two days (N=14, 22 ± 1,75 years) with a total of sixty measurements in each subject. Reliability was determined by intraclass correlation coefficient (ICC), coefficient of variation (CV) and typical error of measurement (TEM). Results show high reliability: MT (0,96 a 0,99), PA (0,83 a 0,99) and FL (0,80 a 0,99) ICC; MT (3,12 a 3,84%), PA (3,68 a 6,34%) and FL (3,98 a 6,33%) CV; MT (0,014 a 0,15mm), PA (0,18 a 0,59º) and FL (0,07 a 1,47mm) TEM. These measures should be considered in studies of the impact of conditioning programs in the architecture of the vastus lateralis muscle.