Electromyographic activity in superficial muscles of the thigh and hip during the back squat to three different depths with relative loading

Issue: Vol. 5 No 3

Published by Journal of Fitness Research, 08/12/2016. Volume 5.3

Tags: Biceps Femoris , Gluteus Maximus , Squat Depth , Surface EMG , Vastus Lateralis , Vastus Medialis Oblique.

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  1. Benjamin Hammond
    Faculty of Arts & Sciences, Edge Hill University
  2. Pascual Marques-Bruna (Corresponding Author)
    Faculty of Arts & Sciences, Edge Hill University
  3. Eric Chauhan
    Faculty of Arts & Sciences, Edge Hill University
  4. Craig Bridge
    Faculty of Arts & Sciences, Edge Hill University


Introduction: Inconclusive previous research on squat depth and the evoked electromyography (EMG)activity muddles our understanding of muscle recruitment in the back squat. This study determined EMGactivity as a function of squat depth in four superficial muscles of the lower limb using relative loading.

Method: Eight resistance trained males (mean ± SD age: 21 ± 1 years) performed back squats to partial,parallel and full depth using depth-relative 5-repetition–maximum loads. Muscle activity in the vastus medialis oblique (VMO), vastus lateralis (VL), gluteus maximus (GM), and biceps femoris (BF) during the concentric and eccentric phases of the squat was determined using surface electromyography. Peak (PeakEMG), mean (Mean EMG), and integrated (iEMG) EMG normalised to their respective maximum voluntary isometric contraction (MVIC) for each muscle were evaluated.

Results: Three-way Anovas and Sidak post-hoc analysis revealed significant effects for squat type (p =0.021 - 0.001), squat phase (p = 0.001), and muscle (p = 0.001). The significant differences were between the partial and the parallel squat (p = 0.016 - 0.001); for iEMG significant effects were also found between the partial and full squat (p = 0.001). The VMO elicited the highest EMG activity (e.g., Peak EMG 93.4 ± 36.9%MVIC; parallel squat, concentric) and the BF the lowest (e.g., Peak EMG 49.9 ± 14.7%). Greater GM activity occurred in parallel squats compared to full squats (mean difference in Peak EMG = 9.1% MVIC).

Conclusion: The findings suggest that squatting to the parallel position or lower induces optimal contractile stimulation of the quadriceps. Squatting to parallel depth maximises EMG activation of the GM, possibly due to a more advantageous external moment arm or a reduction in neural drive.

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Article Title

Electromyographic activity in superficial muscles of the thigh and hip during the back squat to three different depths with relative loading

Journal Title

Journal of Fitness Research Volume 5.3

Online Publication Date


Author Names

Benjamin Hammond
Pascual Marques-Bruna (Corresponding Author)
Eric Chauhan
Craig Bridge
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