title: Quantitative MRI of vastus medialis, vastus lateralis and gluteus medius muscle workload after squat exercise: comparison between squatting with hip adduction and hip abduction.
abstract: The aim of the present study was to evaluate the use MRI to quantify the workload of gluteus medius (GM), vastus medialis (VM) and vastus lateralis (VL) muscles in different types of squat exercises. Fourteen female volunteers were evaluated, average age of 22 ± 2 years, sedentary, without clinical symptoms, and without history of previous lower limb injuries. Quantitative MRI was used to analyze VM, VL and GM muscles before and after squat exercise, squat associated with isometric hip adduction and squat associated with isometric hip abduction. Multi echo images were acquired to calculate the transversal relaxation times (T2) before and after exercise. Mixed Effects Model statistical analysis was used to compare images before and after the exercise (ΔT2) to normalize the variability between subjects. Imaging post processing was performed in Matlab software. GM muscle was the least active during the squat associated with isometric hip adduction and VM the least active during the squat associated with isometric hip abduction, while VL was the most active during squat associated with isometric hip adduction. Our data suggests that isometric hip adduction during the squat does not increase the workload of VM, but decreases the GM muscle workload. Squat associated with isometric hip abduction does not increase VL workload.
authors.affiliation: Departamento de Ciências da Saúde Aplicadas ao Aparelho Locomotor.
authors.forename: Augusto P
authors.initials: AP
authors.lastname: Baffa
authors.forename: Lilian R
authors.initials: LR
authors.lastname: Felicio
authors.forename: Marcelo C
authors.initials: MC
authors.lastname: Saad
authors.forename: Marcello H
authors.initials: MH
authors.lastname: Nogueira-Barbosa
authors.forename: Antonio C
authors.initials: AC
authors.lastname: Santos
authors.forename: Débora
authors.initials: D
authors.lastname: Bevilaqua-Grossi
keywords: T2; gluteus medius; muscle functional magnetic resonance; proton relaxation time; quantitative MRI; squat exercise; vastus medialis