For muscle growth, the trials favour squatting at least to parallel, with deeper squats growing more glute and inner-thigh muscle. In one 10-week trial, full squats grew the glutes about three times as much as half squats (6.7% vs 2.2%), while the front of the thigh grew about equally at both depths2.
Depth changes which muscles do the work. That is why the answer depends on which muscle you are asking about.
What the depths mean
Squat depth is usually described by how far the knee bends. A straight leg is 0°.
- Half squat: knees bent to about a right angle (90°). Thighs stay well above horizontal.
- Parallel squat: the top of the thigh roughly level with the floor.
- Full (deep) squat: as low as a person can go with control. In the main trial below, that was about 140° of knee bend5.
Muscle volume is the size of a whole muscle, measured with MRI (a body scanner that images the muscle in slices). It is the most direct measure of growth these trials used.
In plain terms: "half" stops around a right angle at the knee; "full" goes as low as the hips and ankles allow.
What was studied
The key trial, by Kubo and colleagues, randomly assigned 17 men to full squats (8 men) or half squats (9 men). Both groups squatted twice a week for 10 weeks2. The men were untrained, and the sets were heavy: three sets rising from 60% to 90% of their one-rep max (the heaviest load they could lift once), then sets of eight5. MRI measured four muscle groups before and after2.
| What | Full squat | Half squat |
|---|---|---|
| Men | 8 | 9 |
| Knee bend at the bottom | about 140° | about 90° |
| Sessions | 2 a week, 10 weeks | 2 a week, 10 weeks |
| Measure | MRI muscle volume | MRI muscle volume |
An earlier trial by Bloomquist and colleagues compared deep squats (0–120° of knee bend) with shallow squats (0–60°) in 17 male students for 12 weeks1. A third, by Pallarés and colleagues, trained 53 resistance-trained men at full, parallel or half depth for 10 weeks and measured strength rather than size3.
What the studies found
Glutes and inner thigh grew more with full squats. In the Kubo trial, gluteus maximus volume rose 6.7% with full squats and 2.2% with half squats. The adductors, the inner-thigh muscles, rose 6.2% and 2.7%. Both gaps were statistically significant2.
Muscle volume change after 10 weeks, half vs full squats · %
Half squat (about 90°) Full squat (about 140°)
The front of the thigh grew about equally. The knee extensors (the quads) grew 4.9% with full squats and 4.6% with half squats, and both increases were significant2. The rectus femoris, the one quad muscle that also crosses the hip, did not change in either group. Neither did the hamstrings2.
Very shallow squats fell behind even for the quads. In the Bloomquist trial, deep squats (to 120°) produced greater increases in front-thigh muscle area than shallow squats (to 60°)1. So 60° was not deep enough for the quads, while 90° was, in these two trials.
Strength followed the depth trained. Full-squat max rose 31.8% with full-squat training and 11.3% with half-squat training. Half-squat max rose 24.2% with full-squat training and 32.0% with half-squat training, a gap that was not statistically significant2. In trained men, only the full-squat group improved its max at all three depths tested; the half-squat group showed no gains in strength or jump and sprint tests3.
In plain terms: the deeper the squat, the more the glutes and inner thigh grew; the quads needed at least a right angle at the knee.
The nuance
Why depth matters for the glutes. The glutes extend the hip, and a deeper squat bends the hip further, so the glutes work through a longer range. This is the usual mechanical explanation, not something these trials measured directly. The same idea, training muscles through their stretched range, runs through the research on lengthened partials versus full range of motion.
"Full" does not have to mean "as deep as physically possible." The 2025 glute review looked at four squat studies. Its authors wrote that "ROM matters for GMax hypertrophy; however, squatting till parallel should be enough"5. ROM is range of motion and GMax is the gluteus maximus. They also noted that not everyone can reach full depth, and that working within one's own limits matters more5.
The quads are less picky past a right angle. Kubo's half squat reached 90° and matched the full squat for quad growth2. Bloomquist's shallow squat stopped at 60° and did not1. Between those two, the evidence is thin.
The hamstrings barely grow from squats at any depth. They did not change in either Kubo group2. For what the squat trains, see back squat muscles worked.
Broader evidence points the same way. A 2021 meta-analysis of 16 range-of-motion studies found full range produced more lower-body growth than partial range, with an effect size of 0.88 (an effect size expresses a difference in units of spread; 0.88 is large)4.
How the squat-depth evidence built up
- 2013BloomquistDeep (0–120°) beat shallow (0–60°) for front-thigh muscle area, 17 students
- 2019KuboFull beat half for glutes and adductors on MRI; quads equal, 17 men
- 2020PallarésFull squats raised strength at every depth in 53 trained men
- 2021Pallarés meta-analysisFull range grew more lower-body muscle across 16 studies
- 2025Krause Neto reviewParallel or deeper grows the glutes; parallel "should be enough"
In plain terms: to parallel or below covers the glutes and quads; half squats still grow the quads but leave glute growth on the table.
What this means in practice
The trials describe what happened to groups, not what depth fits one body. The groups that grew the most glute and inner-thigh muscle squatted to about 140° of knee bend, with heavy loads, twice a week25. Depth that a person can reach with control, at parallel or below, is the range the 2025 review pointed to5.
Going deeper usually means lifting a lighter load at first. That is expected: a full squat is a longer lift. Over weeks the load climbs again; see what progressive overload is and how much weight to start with. Weekly sets matter as much as depth; see how many sets per muscle group per week.
The studies at a glance
| Study | Who was studied | Key result | Year |
|---|---|---|---|
| Bloomquist et al., *Eur J Appl Physiol*1 | 17 male students, 12 weeks | Deep squats (0–120°) grew more front-thigh muscle area than shallow squats (0–60°) | 2013 |
| Kubo et al., *Eur J Appl Physiol*2 | 17 untrained men, 10 weeks, MRI | Glutes +6.7% full vs +2.2% half; adductors +6.2% vs +2.7%; quads similar | 2019 |
| Pallarés et al., *Eur J Sport Sci*3 | 53 trained men, 10 weeks | Full squats raised strength at all depths; half squats showed no gains | 2020 |
| Pallarés et al., *Scand J Med Sci Sports*4 | 16 studies pooled | Full range grew more lower-body muscle than partial range (effect size 0.88) | 2021 |
| Krause Neto et al., *Front Physiol*5 | 12 glute studies, 318 people | Squatting to parallel or deeper grew the glutes; parallel "should be enough" | 2025 |
| Hammami et al., *J Funct Morphol Kinesiol*6 | 28 trained boys about 14 years old, 8 weeks | Estimated thigh size grew with both depths, no significant difference; full squats better for body fat and bar speed | 2025 |
Limits worth knowing
- Small trials. The two MRI and muscle-area trials had 17 men each21.
- Men only in the growth trials. The review pooled 144 women and 174 men across all glute studies, not only squat studies5.
- Mostly untrained. Kubo's men were untrained; results in experienced lifters may differ.
- Abstract only for Kubo, Bloomquist and both Pallarés papers. For Kubo, the knee angles and loads come from the full-text review that describes it5.
- No joint or comfort outcomes are covered here. This page is about muscle growth and strength only.
Latest research
The newest squat-depth trial we opened is a 2025 study of 28 trained 14-year-old tennis players over 8 weeks6. Thigh size grew with both full and half squats, with no significant difference between them; full squats did outperform half squats for body fat and bar speed6. It is a weak test of the question: thigh size was estimated from tape measurements and skinfolds rather than scanned, and the glutes were not measured6. It does agree with Kubo that the front of the thigh grows at either depth. We found no newer MRI trial of squat depth in adults.
The short version
- Deeper squats grew more glute and inner-thigh muscle than half squats in the key MRI trial.
- The quads grew about equally at a right-angle depth and at full depth, but less with very shallow squats.
- A 2025 review concluded that parallel should be enough for the glutes.
- The evidence is a handful of small trials, mostly in untrained men.
Educational overview only — not medical advice.
