Frog Squat

What the frog squat actually trains

A frog squat is a deep bodyweight squat performed with the heels together or nearly touching and the toes turned well out to the sides.

The quadriceps do most of the work, particularly through the deepest part of the range. The adductors are stretched hard by the turned out position, the calves are loaded as the heels rise, and the abs stabilise a torso that has nowhere to lean.

The stance is what makes it different. In a normal squat, a wide base and moderate toe angle let you split the work between your hips and your knees. Bring the heels together and the hips have nowhere to travel backwards to, so the only way down is by bending the knees. That makes this the most knee dominant squat pattern most people will ever do, sissy squats aside.

It also makes it very deep. With the knees free to travel forward and the hips staying more or less over the feet, most people can drop until their hamstrings rest on their calves, which is a range they never reach in a loaded squat.

Two honest points follow.

The first is that this is largely mobility work. Getting into and out of a fully flexed knee and ankle position under control, repeatedly, is genuinely useful, and it transfers to your deep squat position with a barbell. That is a real benefit.

The second is that it is unloaded. Kubo and colleagues found deep squat training produced greater muscle growth than shallow squatting, but the loads involved were substantial. Bodyweight in this position does not approach them. This is not a leg builder and it is not pretending to be one.

Setting up and executing

Stand with the heels together or nearly touching, and turn the toes out to roughly forty five degrees each.

Hold the arms out in front of you for balance and brace the abs lightly.

Sit straight down, keeping the chest as tall as you can manage. The knees will travel forward well past the toes, which is exactly what should happen in this stance.

Let the heels lift if they need to. Most people cannot hold this position flat footed at depth, and fighting it just limits the range.

Descend until the hamstrings meet the calves, or as deep as you control, and pause for a beat rather than rebounding out.

Push back to standing, and repeat.

The mistakes that cost you the most

Fighting the heel lift is the most common one and it comes from applying a barbell squat rule to a movement it does not apply to. With a loaded bar on your back, heels lifting means the load is drifting forward and the lift is going wrong. With bodyweight and the heels together, rising heels are just what deep ankle and knee flexion looks like in that stance. Let them come up.

Folding the chest forward defeats the purpose. The moment you lean, the hips take over and the knee dominant quality that made this worth doing disappears. Keep the chest tall even if it costs you depth at first.

Bouncing at the bottom skips the position you came for. Pause, feel the deepest range, then stand.

Rushing the range is the injury risk here, small as it is. Full knee flexion under any load is a position most people spend no time in, and building tolerance to it takes weeks. Work to the depth you control.

And expecting it to build legs is the framing mistake. Bloomquist and colleagues showed depth matters, but their subjects were squatting with heavy loads. Depth without load is a mobility stimulus, not a hypertrophy one.

Sets, reps and rest by goal

Higher reps, short rest, and no attempt to make it heavy.

For muscle gain, three sets of twelve to twenty with a minute, understanding that the contribution is modest. For strength, three sets of ten to fifteen with ninety seconds, where the strength in question is positional rather than maximal. In a fat loss phase, three sets of fifteen to twenty five with forty five seconds.

The useful progressions are range and time, not load. Add depth over weeks. Add a two or three second pause at the bottom. Slow the descent to four seconds.

Schoenfeld and colleagues found a dose response between weekly hard sets and hypertrophy, which is worth reading here as an argument for putting your leg volume somewhere else and using this as preparation.

Refalo and colleagues found training close to failure is not necessary for growth, which matters little here since failure on an unloaded squat is a conditioning event rather than a muscular one.

Where it fits in your split

In the warm up of a lower body session, or as a finisher.

On push, pull and legs it goes on legs day, before the main squatting. On a bro split it opens leg day. On an upper and lower split it prepares you for deep squatting. On a full body programme it is a fast warm up needing no equipment. On a bodyweight programme it is one of several squat patterns worth rotating through.

The best use is genuinely as preparation. Two sets of ten frog squats before you get under a bar does more for your squat depth than static stretching, because it takes the knees and ankles through the range you are about to load.

The second use is at home, in a bodyweight leg circuit, where its knee dominance complements more hip dominant patterns.

What it should not be is the centrepiece of your leg training. If your legs are the priority and you have access to weights, put the time into loaded squatting and keep this in the warm up.

Two or three times a week is fine, since there is nothing to recover from.

Variations worth knowing

The air squat uses a shoulder width stance and a more natural toe angle, splitting the demand between hips and knees rather than concentrating it at the knee.

The Cossack squat travels side to side over a wide stance and adds a substantial adductor stretch, which pairs well with this in a mobility sequence.

A deep squat hold sits in the bottom position for thirty to sixty seconds rather than repping it, which builds tolerance to the position faster than repetitions do.

Heels elevated air squats put plates under the heels and reach similar depth while keeping the whole foot down, which suits people who want the knee flexion without the balance demand.

The sissy squat takes knee dominance to its logical extreme, extending the hips while the knees flex fully, and genuinely loads the rectus femoris.

And the goblet squat is where to go once this pattern is comfortable, since it keeps the upright torso and adds the load that actually builds muscle.

What the evidence says

Kubo and colleagues trained squats at different depths and found greater quadriceps and gluteal growth with full depth, which establishes depth as valuable and, by implication, makes a case for training the mobility to achieve it.

Hartmann and colleagues reviewed knee and spinal loading across squat depths and found no evidence that deep squatting harms the knee in trained people, which is the direct answer to anybody worried about a heels together, knees forward position.

Escamilla's analysis of knee biomechanics during the squat found that forces on the knee are well tolerated through a controlled range, supporting deep unloaded work as a preparation strategy rather than a hazard.

Schoenfeld's review of squatting kinematics explains why stance width and foot angle change the balance between hip and knee extension, which is exactly the mechanism a narrow, turned out stance exploits.

Pedrosa and colleagues found training at long muscle lengths produced favourable adaptations, which supports spending time in deep positions, though their work involved loaded training rather than bodyweight movement.

Schoenfeld and colleagues on volume and Refalo and colleagues on proximity to failure supply the programming context, and together they explain why an unloaded squat contributes little to hypertrophy regardless of how many you do.

Common questions

Is it bad that my heels come up?

No. With the heels together and the toes turned out, most people physically cannot stay flat footed at depth. The rising heel is a consequence of the stance rather than a technique error, and unlike a loaded barbell squat there is no load drifting forward to worry about.

Does this build muscle?

Barely, past the first few weeks of training. It is unloaded, and while Kubo and colleagues showed that squat depth drives growth, that finding came from heavy training. Treat this as mobility work and pattern practice, and get your leg growth from loaded squatting.

How is it different from an air squat?

The stance. An air squat uses a shoulder width base and splits the work between hips and knees. A frog squat brings the heels together, which removes the option of sitting the hips back and forces almost all the movement into the knees. It is deeper and considerably more demanding on ankle and knee mobility.

Is deep knee flexion safe?

Yes, for healthy knees. Hartmann and colleagues reviewed joint loading across squat depths and found no evidence that deep squatting damages the knee in trained individuals. What does cause trouble is going from no deep work at all to a lot of it in a week, so build the range gradually.

Can I add weight to it?

You can hold a light dumbbell at your chest, and it does help. But once you are doing that, you have built a narrow stance goblet squat, and a normal stance goblet squat is a better exercise for the same effort. Use the frog squat unloaded and load a different pattern.