title: The effect of back squat depth on the EMG activity of 4 superficial hip and thigh muscles.
abstract: The purpose of this study was to measure the relative contributions of 4 hip and thigh muscles while performing squats at 3 depths. Ten experienced lifters performed randomized trials of squats at partial, parallel, and full depths, using 100-125% of body weight as resistance. Electromyographic (EMG) surface electrodes were placed on the vastus medialis (VMO), the vastus lateralis, (VL), the biceps femoris (BF), and the gluteus maximus (GM). EMG data were quantified by integration and expressed as a percentage of the total electrical activity of the 4 muscles. Analysis of variance (ANOVA) and Tukey post hoc tests indicated a significant difference (p < 0.001*, p = 0.056**) in the relative contribution of the GM during the concentric phases among the partial- (16.9%*), parallel- (28.0%**), and full-depth (35.4%*) squats. There were no significant differences between the relative contributions of the BF, the VMO, and the VL at different squatting depths during this phase. The results suggest that the GM, rather than the BF, the VMO, or the VL, becomes more active in concentric contraction as squat depth increases.
authors.affiliation: The Department of Health and Exercise Science, Furman University, 3300 Poinsett Highway, Greenville, South Carolina 29613, USA. tony.caterisano@furman.edu
authors.forename: Anthony
authors.initials: A
authors.lastname: Caterisano
authors.forename: Raymond F
authors.initials: RF
authors.lastname: Moss
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Pellinger
authors.forename: Katherine
authors.initials: K
authors.lastname: Woodruff
authors.forename: Victor C
authors.initials: VC
authors.lastname: Lewis
authors.forename: Walter
authors.initials: W
authors.lastname: Booth
authors.forename: Tarick
authors.initials: T
authors.lastname: Khadra
mesh_terms: D004576:Electromyography; D015444:Exercise / Q000502:physiology*; D006615:Hip; D006801:Humans; D018482:Muscle, Skeletal / Q000502:physiology*; D013848:Thigh; D014891:Weight Lifting / Q000502:physiology*