How is this different from a pistol squat?

The movement is the same, but holding the straps removes most of the balance challenge and lets your arms take a little of the load when you need it. That makes it a practical way to build strength through the full range before trying the unassisted Pistol Squat.

How do I make it easier or harder?

Leaning back further against the straps lets them carry more of your weight, so it gets easier, while standing more upright leaves less help available. You can also change the depth, slow down the lowering phase or hold just one strap to make it harder.

Why is the free leg held out in front?

Holding the free leg straight in front is what makes this a pistol pattern, and it counterbalances the hips as they sit low behind the standing foot. In a lab study of 17 healthy adults doing unassisted single-leg squats, gluteal activity while lowering was higher with the free leg extended in front, pistol style, than with it bent and held behind the body.

How deep should I go?

Go as low as you can while keeping the standing heel down, the knee in line with the toes and the lowering slow and controlled. A full rep ends with the hips close to the standing heel, but building toward that over a few weeks is better than forcing it on the first day.

How many reps should I do?

Because it is a hard body-weight exercise for one leg at a time, 3 to 4 sets of 5 to 10 controlled reps per leg suits most people. Once you can do 10 clean reps with very little help from the straps, it is time to stand more upright or try the unassisted version.

TRX Single-Leg Squat

What Is the TRX Single-Leg Squat?

TRX Single-Leg Squat is a compound exercise that primarily targets the quads and also engages the glutes, the adductors and the muscles that keep the hip, knee and ankle steady. It is an intermediate-level movement in which you hold a pair of suspension straps for balance while squatting all the way down on one leg, with the other leg held straight out in front. That is the same shape as the Pistol Squat, with the straps taking away most of the balance problem.

The straps are what make this variation useful. They let you sit into a deep single-leg squat and stand back up before you have the strength and control for an unassisted pistol, and you can lend yourself a little arm help through the hardest part of the rise. Coaches use it as the bridge between two-legged squatting and the full pistol, and as a way to build single-leg strength and expose differences between the left and right legs without any added load.

The quadriceps of the standing leg do most of the work, because the knee bends through nearly its full range while one leg carries your body weight. The glutes work hardest near the bottom and through the first part of the rise, and the adductors help extend the hip out of the deepest position. The gluteus medius and the muscles around the outside of the hip keep the pelvis level and the knee in line with the foot, while the calf and foot muscles control the ankle as the shin travels forward. The more you lean back and pull on the straps, the more the work shifts to your arms and the less your leg has to do.

This exercise suits anyone working toward a pistol squat, runners and field-sport athletes who want more single-leg strength, and people training at home with only a suspension trainer. Before trying it, you should be able to do a full-depth Bodyweight Squat and a controlled Bodyweight Bulgarian Split Squat. If the full depth is still too much, start with the two-legged TRX Squat or stop each rep at a depth you can control and lower a little further each week.

Muscles Worked

MuscleActivation

Vastus Lateralis: Primary
Vastus Medialis: Primary
Gluteus Maximus: High
Rectus Femoris: High
Adductor Magnus: Medium
Gluteus Medius: Medium
Biceps Femoris: Low
Rectus Abdominis: Low
Soleus: Low
Tensor Fasciae Latae: Low

Instructions

Adjust the straps to mid-length and stand facing the anchor point, holding a handle in each hand.
Step your feet together and lean back slightly until the straps are taut, with your arms straight and reaching up toward the anchor at about head height.
Shift your weight onto one foot and lift the other leg off the floor, reaching it straight out in front of you.
Sit your hips back and down on the standing leg, letting your straight arms rise toward the anchor as you lower.
Keep the standing heel flat and the knee tracking in line with the toes as the shin moves forward.
Lower under control until your hips are close to your standing heel, or as deep as you can control, with the free leg held straight and just off the floor.
Drive through the whole standing foot to stand back up, using the straps only for balance and as little pull as you need.
At the top, set the free foot down to reset if needed, then repeat for all reps before switching legs.

Common Mistakes

Pulling up with the arms
Rowing yourself out of the bottom with the straps turns a leg exercise into an arm exercise, so use them only to steady yourself and add as little help as you need.
Heel lifting
Letting the standing heel come off the floor shifts the load onto the toes and the front of the knee, and usually means the ankle lacks mobility or the depth is more than you can control.
Knee caving inward
Allowing the standing knee to drift inside the foot strains the knee and hip, so keep it tracking in line with the toes throughout.
Letting the straps go slack
Losing tension in the straps on the way down removes the support right where balance is hardest and causes a sudden drop or jerk at the bottom.
Dropping into the bottom
Collapsing through the last part of the descent instead of lowering under control loads the knee at its deepest bend and skips the hardest part of the exercise.

Injuries

TRX Single-Leg Squat is a medium risk exercise when performed with proper technique. The straps make a loss of balance much less likely than in an unassisted pistol, but the standing knee still bends very deeply under your full body weight. The front of the knee, around the kneecap and patellar tendon, takes the most stress, followed by the ankle as the shin moves forward and the hip if the pelvis tips or the knee drifts inward.

Check that the anchor is secure and the straps are even before every set, and keep light tension on them the whole time so you never drop onto slack straps. Keep the standing heel flat and the knee pointing in the same direction as the toes, and only go as deep as you can control on the way down and on the way up. If the heel lifts, reduce the depth and work on ankle mobility rather than forcing the range.

To make it easier, lean back a little more against the straps, use a shallower depth, or go back to the TRX Squat or the Bodyweight Bulgarian Split Squat. To progress, stand more upright so the straps can help less, slow the lowering phase, hold only one strap, and eventually move on to the unassisted Pistol Squat.

Stop the set if you feel sharp pain in the knee, pain at the front of the knee that builds with each rep, a pinching feeling at the front of the ankle or hip, or if the knee keeps collapsing inward no matter how much you lean on the straps.

Overview

Primary Focus: Quads
Equipment: Suspension trainer and body weight
Modality: Strength
Difficulty: Intermediate

Alternative Exercises

Other Names for the TRX Single-Leg Squat

The TRX Single-Leg Squat is also known as:

TRX Pistol Squat
TRX Assisted Pistol Squat

Frequently Asked Questions

Q: How is this different from a pistol squat?: The movement is the same, but holding the straps removes most of the balance challenge and lets your arms take a little of the load when you need it. That makes it a practical way to build strength through the full range before trying the unassisted Pistol Squat.
Q: How do I make it easier or harder?: Leaning back further against the straps lets them carry more of your weight, so it gets easier, while standing more upright leaves less help available. You can also change the depth, slow down the lowering phase or hold just one strap to make it harder.
Q: Why is the free leg held out in front?: Holding the free leg straight in front is what makes this a pistol pattern, and it counterbalances the hips as they sit low behind the standing foot. In a lab study of 17 healthy adults doing unassisted single-leg squats, gluteal activity while lowering was higher with the free leg extended in front, pistol style, than with it bent and held behind the body.
Q: How deep should I go?: Go as low as you can while keeping the standing heel down, the knee in line with the toes and the lowering slow and controlled. A full rep ends with the hips close to the standing heel, but building toward that over a few weeks is better than forcing it on the first day.
Q: How many reps should I do?: Because it is a hard body-weight exercise for one leg at a time, 3 to 4 sets of 5 to 10 controlled reps per leg suits most people. Once you can do 10 clean reps with very little help from the straps, it is time to stand more upright or try the unassisted version.