Hip thrust and back squat training elicit similar gluteus muscle hypertrophy and transfer similarly to the deadlift

Abstract

Purpose: We examined how set-volume equated resistance training using either the back squat (SQ) or hip thrust (HT) affected hypertrophy and various strength outcomes.

Methods: Untrained college-aged participants were randomized into HT or SQ groups. Surface electromyograms (sEMG) from the right gluteus maximus and medius muscles were obtained during the first training session. Participants completed nine weeks of supervised training (15-17 sessions), before and after which we assessed muscle cross-sectional area (mCSA) via magnetic resonance imaging and strength via three-repetition maximum (3RM) testing and an isometric wall push test.

Results: Glutei mCSA growth was similar across both groups. Estimates [(-) favors HT; (+) favors SQ] modestly favored the HT compared to SQ for lower [effect ± SE, -1.6 ± 2.1 cm²], mid [-0.5± 1.7 cm²], and upper [-0.5 ± 2.6 cm²], but with appreciable variance. Gluteus medius+minimus [-1.8 ± 1.5 cm²] and hamstrings [0.1 ± 0.6 cm²] mCSA demonstrated little to no growth with small differences between groups. Thigh mCSA changes were greater in SQ for the quadriceps [3.6 ± 1.5 cm²] and adductors [2.5 ± 0.7 cm²]. Squat 3RM increases favored SQ [14 ± 2.5 kg] and hip thrust 3RM favored HT [-26 ± 5 kg]. 3RM deadlift [0 ± 2 kg] and wall push strength [-7 ± 13 N] similarly improved. All measured gluteal sites showed greater mean sEMG amplitudes during the first bout hip thrust versus squat set, but this did not consistently predict gluteal hypertrophy outcomes.

Conclusion: Nine weeks of squat versus hip thrust training elicited similar gluteal hypertrophy, greater thigh hypertrophy in SQ, strength increases that favored exercise allocation, and similar strength transfers to the deadlift and wall push.

Keywords: Hip thrust; back squat; gluteus maximus; strength.

Figure 1.. Study design overview

Figure depicts study design overview described in-text. Abbreviations: PRE, pre-intervention testing visit; POST, post-intervention testing visit; HT, barbell hip thrust; SQ, barbell squat; body comp., body composition testing using bioelectrical impedance spectroscopy; MRI, magnetic resonance imaging; sEMG, electromyography.

Figure 2.. Wall push demonstration

Figure depicts the wall push test with one of the co-authors (M.D.R.) and shows force tracing..

Figure 3.. CONSORT diagram

Figure depicts participant numbers through various stages of the intervention. All participants were included in data analysis unless there were technical issues precluding the inclusion of data (e.g., EMG clipping)..

Figure 4.. Surface electromyogram (sEMG) amplitudes during the back squat and barbell hip thrust

During the first session, all participants performed both back squats and barbell hip thrusts while we recorded sEMG amplitudes. (a) Representative sEMG electrode placement is depicted on a co-author in panel. (b) Data depict mean (left) and peak (right) sEMG amplitudes during one 10RM set of hip thrusts and one 10RM set of back squats. As 34 participants partook in this test, sample sizes vary due to incomplete data from electrode slippage or clipping. Bars are mean ± SD, and individual participant values are depicted as dots. (c) Representative data from one participant..

Figure 6.. Gluteus musculature mCSA changes following back squat and barbell hip thrust training, assessed using MRI

Figure depicts pre-to-post intervention MRI-derived muscle cross-sectional area (mCSA) summed values for (a) left + right (L+R) upper gluteus maximus, (b) L+R middle gluteus maximus, (c) L+R lower gluteus maximus, (d) L+R gluteus medius+minimus. Data include 18 participants in the hip thrust group and 16 participants in the back squat group. Graphs contain change scores with individual participant values depicted as dots. (e) Three pre and post representative MRI images are presented from the same participant with white polygon tracings of the L+R upper gluteus maximus and gluteus medius+minimus (top), L+R middle gluteus maximus (middle), and L+R lower gluteus maximus (bottom)..

Figure 7.. Thigh musculature mCSA changes following back squat and barbell hip thrust training, assessed using MRI

Figure depicts MRI-derived muscle cross-sectional area (mCSA) average change scores for left and/or right (a) quadriceps, (b) adductors, and (c) hamstrings. Data include 18 participants in the hip thrust group and 16 participants in the back squat group. Bar graphs contain change scores with individual participant values depicted as dots. (d) A representative pre- and post-intervention MRI image is presented with white polygon tracings of the quadriceps (denoted as Q), adductors (denoted as ADD), and hamstrings (denoted as H)..

Figure 8.. Strength outcomes following back squat and barbell hip thrust training

Figure depicts change scores for (a) 3RM barbell back squat values, (b) 3RM barbell hip thrust values, (c) 3RM barbell deadlift values, and (d) horizontal ground reactive forces (GRF) during the wall push as demonstrated in Figure 2. Data include 18 participants in the hip thrust group and 16 participants in the back squat group. .