When it comes to squats, one of the most debated topics in the gym and sports science world is squat depth. Should you go ass-to-grass (ATG) or stop at parallel? Is there a real benefit to going deep for glute development, or are partial reps at 90° just as effective?
Let’s dive into the science behind squat depth and what it means for your training.
What does the research say about squat depth?
Squat depth is generally categorized as:
- Partial squat: ~90° knee angle or higher
- Parallel squat: hip crease flush with knees (~90°)
- Deep squat (ATG): hips go below the knees, my favorites;)
Differences in muscle activation
Several studies show that deeper squats activate more muscles, especially the glutes and adductors. For example:
- Bryanton et al. (2012) found that deeper squats increase mechanical demands on the glutes and hamstrings.
- Kubo et al. (2019) compared full vs. partial squats for 10 weeks and found greater increases in gluteal muscle and adductor size in the deep squat group.
- Contreras et al. (2020) confirmed that full squats result in more total glute activation over the full range of motion.
Summary: If your goal is maximum growth of the glutes, then full depth (as deep as your mobility allows without compensation) is probably the best option.
What about partial squats at 90°?
It’s not just about going deep. There are strategic reasons to train squats at 90° or even higher:
Load management and strength gain
- Partial squats allow you to lift heavier weights, which means you can train with higher absolute loads. This can improve neuromuscular efficiency and joint-specific strength at certain angles.
- A study by Hartmann et al. (2012) showed that partial squats led to greater improvements in vertical jump and sprint performance in athletes compared to full squats. Why? Because most explosive movements occur in a more upright, 90° range of motion.
Mental and joint recovery
- For people with knee or hip problems, partial squats can be a safer way to maintain strength without aggravating joint stress.
- Partial ROM squats can also be great during deload weeks or if you are focusing on speed and strength rather than hypertrophy.
Growth of glutes: Full versus partial squats
If your main goal is gluteal muscle hypertrophy, you want to do the following:
- Prefer full-range squats, ideally below parallel. They stretch the glutes under load, an important factor in muscle growth.
- Combine with hip thrusts or Romanian deadlifts, which also load the glutes in an extended and shortened position.
But that doesn’t mean partial squats are useless – far from it. Incorporating partial squats with heavy loads can still support gluteal muscle development by adding volume, strength at specific joint angles and neural adaptation.
What is the best strategy?
The answer depends on your goal:
Don’t get caught up in the endless discussion about squat depths would be my advice. Use them wisely depending on your goals. It’s a great movement and can be used in different ways, so instead of asking “Which is better?”, ask “When is each movement best?”.
