Comparison of Muscle Activation Between Back Squats and Belt Squats.
Level 3 - non-randomized controlled study
Non-randomized within-subject comparative crossover study (graded by design analogy for biomechanics research)
PubMed 28595237 · doi:10.1519/JSC.0000000000002052
What was done
Thirty-one participants (16 men and 15 women) underwent anthropometric assessments, a familiarization session, and two testing sessions to evaluate 5 repetition maximum (5RM) loads for traditional barbell back squats and machine belt squats. Surface electromyography (sEMG) measured muscle activation across four bilateral muscle groups: vastus medialis, vastus lateralis, rectus femoris, and gluteus maximus. Regression models were also calculated to estimate belt squat loads based on back squat load, training experience, and anthropometrics.
What was found
Back squats produced significantly higher muscle activation in the gluteus maximus compared to belt squats on both the left side (0.84 ± 0.45 vs. 0.69 ± 0.22, p = 0.015) and right side (0.86 ± 0.45 vs. 0.71 ± 0.29, p = 0.004). Specific EMG values for the quadriceps muscles (vastus medialis, vastus lateralis, rectus femoris) were not numerically reported in the abstract.
Why it matters
Belt squats unload the spine by placing resistance at the hips, making them a common alternative for lifters managing axial loading constraints. These findings suggest that while belt squats serve as an alternative exercise, they recruit the gluteus maximus less than traditional back squats at matched 5RM intensities.
Limits
The study evaluated a small sample of 31 individuals, and the abstract does not state whether the order of testing conditions was randomized. Long-term training adaptations, spinal loading, and detailed quadriceps EMG data were not provided in the abstract.
Cited by
- supports Belt squats eliminate axial loading on the spine compared to traditional barbell squats.