Single-Leg Low Box Squat
What Is the Single-Leg Low Box Squat?
Single-Leg Low Box Squat is a compound exercise that primarily targets the quadriceps and also engages the glutes and hip stabilizers. It is an advanced-level movement that lowers one leg down to a low box through a deep range of motion.
The low box sets the depth target for a single-leg squat that sits close to a full Pistol Squat. Touching down lightly before standing back up builds the quad and glute strength, ankle and hip control, and balance a single leg needs to control that much range without a spotting hand or a higher resting point. It has no standard sport test or competition role; it belongs to bodyweight and unilateral leg-strength programming, where it closes the gap between a controlled single-leg squat and the full movement.
Box height is what separates this exercise from the Single-Leg Box Squat: a higher box stops the movement near knee height, while this low box takes the hip well below the knee, closer to the depth of a full Pistol Squat. That extra depth asks more of the quads and glutes through a longer range and increases the balance demand on the standing ankle and hip, so the exercise reads as a harder step on the same progression rather than a different movement.
It suits lifters who already own the higher-box version and can control it for a full set without the knee caving in or the free leg touching down. Someone who cannot yet do that is better served raising the box back up a few inches rather than pushing through the lower depth, since the difficulty here comes from range and balance, not external load.
Muscles Worked
- Vastus Lateralis
- Primary
- Vastus Medialis
- Primary
- Gluteus Maximus
- High
- Gluteus Medius
- Medium
- Rectus Femoris
- Medium
- Gastrocnemius (Medial Head)
- Minimal
Instructions
- Set a low box behind you, roughly shin height, and stand on one leg a short stride in front of it.
- Extend your free leg forward off the ground and reach both arms out in front of you for counterbalance.
- Brace your core and keep your weight on the standing foot, from heel through midfoot.
- Push your hips back and bend the standing knee, lowering under control while keeping the knee tracking over your toes.
- Let your free leg rise as you descend to keep it off the floor, and let your torso lean forward to stay balanced over the standing foot.
- Lower until your hips lightly touch the box, without sitting your full weight down or bouncing off it.
- Drive through the standing leg to return to full hip and knee extension, keeping the knee stable and avoiding any inward collapse.
- Complete all reps on one leg before switching sides.
Common Mistakes
Skipping the progression
Starting at a low box before owning the higher-box version leaves the knee and hip without the control the extra depth demands.
Knee caving inward
The standing knee drifts toward the midline on the way up, usually from weak hip abductors rather than the quads.
Dropping onto the box
Losing control of the descent and falling the last few inches instead of lowering under tension turns the set into a series of bounces.
Using the box to rest and push off
Sitting the full body weight down and shoving off the box borrows momentum that the standing leg should be producing.
Letting the free leg drop or touch down
The non-working leg brushing the floor hands the standing leg a second point of support it is not supposed to have.
Injuries
Single-Leg Low Box Squat is a medium risk exercise when performed with proper technique.
Most of the strain lands on the knee, which works through a deep flexion range under the full weight of one leg, and on the standing hip and ankle, which hold the balance that a two-legged squat does not require. Knee valgus, the knee drifting inward as you stand up, is the most common fault that turns this load into joint stress rather than muscle work.
Keep the box there to catch you rather than treating it as optional, control the descent instead of dropping onto it, and stop the set once the standing knee starts caving in or the free leg needs to touch down for balance. Build ankle and hip mobility before adding depth, since limited dorsiflexion or hip flexion is what usually forces the knee or torso to compensate.
Anyone with existing knee pain in deep flexion, or who cannot yet control the Single-Leg Box Squat at a higher box, should build strength there first. Stop the exercise and raise the box back up if balance breaks down or the knee tracks inward on more than an occasional rep.
- Primary Focus
- Quads
- Equipment
- Body weight and plyo box
- Modality
- Strength
- Difficulty
- Advanced
Alternative Exercises
Frequently Asked Questions
- Q: How is this different from the Single-Leg Box Squat?
The box is lower and the squat goes deeper. The Single-Leg Box Squat stops around knee height; this version lowers the hip well below the knee, which is a harder step on the way to a full Pistol Squat.
- Q: Do I need to sit all the way down on the box?
No. Touch it lightly to confirm depth and keep moving, rather than sitting your full weight down and resting between reps.
- Q: What do I do with my free leg?
Keep it extended out in front of you and off the ground for the whole rep. A slight bend is fine if a straight leg is not available yet, as long as it stays clear of the floor.
- Q: Is this the same as a Pistol Squat?
Not quite. It is a regression that uses the low box to cap the range and give you a light touchpoint, where a full Pistol Squat has no box and no touchpoint at all.
- Q: How do I know I am ready to lower the box further?
You should be able to control several reps on each leg without the knee caving in or the free leg touching down before taking the box any lower.