Hip thrust and back squat training elicit similar gluteus muscle hypertrophy and transfer similarly to the deadlift.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 37877099 · doi:10.3389/fphys.2023.1279170
What was done
Untrained college-aged adults (n = 34) were randomized to 9 weeks of set-volume-equated resistance training performing either barbell hip thrusts (HT, n = 18) or back squats (SQ, n = 16) across 15–17 supervised sessions. Surface electromyography (sEMG) of the gluteus maximus and medius was measured during the first session. Muscle cross-sectional area (mCSA) of the gluteal and leg muscles was assessed before and after training via MRI. Strength was evaluated using three-repetition maximum (3RM) tests (squat, hip thrust, deadlift) and an isometric wall push test.
What was found
Gluteal mCSA increases were similar between groups (effect ± SE favoring HT [-] or SQ [+]): lower gluteal mCSA (-1.6 ± 2.1 cm²; 95% CI: -6.1 to 2.0), mid-gluteal (-0.5 ± 1.7 cm²; 95% CI: -4.0 to 2.6), and upper gluteal (-0.5 ± 2.6 cm²; 95% CI: -5.8 to 4.1). Gluteus medius/minimus (-1.8 ± 1.5 cm²; 95% CI: -4.6 to 1.4) and hamstrings (0.1 ± 0.6 cm²; 95% CI: -0.9 to 1.4) showed minimal growth in both groups. Squat training produced greater mCSA increases in the quadriceps (3.6 ± 1.5 cm²; 95% CI: 0.7 to 6.4) and adductors (2.5 ± 0.7 cm²; 95% CI: 1.2 to 3.9). Strength gains showed exercise specificity: 3RM squat favored SQ (14 ± 2 kg; 95% CI: 9 to 18) and 3RM hip thrust favored HT (-26 ± 5 kg; 95% CI: -34 to -16). Deadlift 3RM change (0 ± 2 kg; 95% CI: -4 to 3) and wall push force (-7 ± 12 N; 95% CI: -32 to 17) improved similarly. Initial gluteal sEMG amplitude was higher during hip thrusts but did not predict hypertrophy.
Why it matters
Hip thrusts and back squats induce equivalent gluteal hypertrophy and deadlift strength transfer, but squats offer broader lower-body muscular development for the quadriceps and adductors. Furthermore, higher acute gluteal EMG activity during hip thrusts failed to produce greater gluteal growth.
Limits
The sample size was small (34 total participants) and restricted to untrained college-aged individuals, limiting direct generalization to trained lifters. The 9-week duration is relatively short, and wide confidence intervals around gluteal growth estimates indicate notable measurement variance.