Skip to content
Crucible Fit
  • The Crucible
  • The Week
  • Programs
  • Train Your Way
  • Pricing
Get Crucible
  • The Crucible
  • The Week
  • Programs
  • Train Your Way
  • Apple Watch
  • Pricing
  • FAQ
  • Training Guides
Get Crucible
Crucible Fit

A daily functional fitness test for iPhone, Apple Watch and Android. Stations, reps and the Crux, sized to your readiness and your kit.

Download on the App StoreGet it on Google Play

Crucible Fit

  • The Crucible
  • The Week
  • Programs
  • Train Your Way
  • Apple Watch
  • Pricing

Explore

  • Training Guides
  • Exercise Library
  • FAQ
  • Press
  • Support

Legal

  • Terms and Conditions
  • Privacy Policy
  • Consumer Health Data Notice

CRUCIBLE FIT™ and Crux by Crucible Fit are trademarks of Crucible Fit, LLC.

© 2026 Crucible Fit, LLC. All rights reserved. Apple, the Apple logo, iPhone and Apple Watch are trademarks of Apple Inc., registered in the U.S. and other countries. App Store is a service mark of Apple Inc. Google Play and the Google Play logo are trademarks of Google LLC.

  1. Home
  2. /
  3. Exercises
  4. /
  5. Core & Abs
  6. /
  7. Bosu Ball Balance Single Leg Squat

Exercise guide

Bosu Ball Balance Single Leg Squat

  • Advanced
  • Compound
  • Rep-based
  • Lower legs
  • Upper legs
  • Waist

This advanced unilateral exercise develops exceptional lower-body strength and ankle stability while forcing the core to stabilize against an unstable surface. It primarily targets the quadriceps and glutes while engaging the calves and obliques for balance.

Reviewed by the Crucible Fit team · Updated June 2026

Watch the Bosu Ball Balance Single Leg Squat demonstrationVideo and instructions for every movement are in the Crucible Fit app.

Muscles worked

Primary

  • Calves
  • Glutes
  • Hamstrings
  • Quadriceps

Secondary

  • Deltoids
  • Rotator cuff
  • Serratus anterior

Equipment

  • Bosu ball

Setup

  1. Place the Bosu ball on the floor with the dome side facing up.
  2. Step one foot onto the center of the dome, ensuring your weight is evenly distributed across the tripod of your foot.
  3. Lift the opposite leg off the floor, extending it slightly forward or bending the knee behind you for balance.
  4. Engage your core and find a fixed focal point at eye level to help maintain stability.

How to do it

  1. Inhale as you slowly hinge at the hips and bend your standing knee to lower into a squat, keeping your chest upright.
  2. Lower yourself until your thigh is nearly parallel to the floor, or as deep as your balance allows without losing form.
  3. Exhale and drive through the mid-foot of the standing leg to return to the starting position.
  4. Maintain a controlled tempo, focusing on a slow 3-second descent to maximize stability.

Form checklist

  • Keep the standing knee tracked directly over the second toe to prevent valgus collapse.
  • Maintain a neutral spine and keep the chest lifted throughout the movement.
  • Keep your hips level and avoid tilting or hiking the hip of the non-working leg.
  • Ensure the core remains braced to minimize the wobbling of the Bosu ball.

Pro tips

  • Imagine 'gripping' the dome with your toes to activate the intrinsic muscles of the foot and improve proprioception.
  • Keep your arms extended in front of you as a counterbalance to manage the shifting center of gravity.

Make it harder

  • Perform the exercise with the Bosu ball flipped over (flat side up) to significantly increase the instability.
  • Hold a light kettlebell in a goblet position or in the hand opposite to the working leg to add a rotational stability challenge.

Frequently asked

What muscles does the bosu ball balance single leg squat work?
The bosu ball balance single leg squat primarily targets the calves, glutes, hamstrings, and quadriceps, and also works the deltoids, rotator cuff, and serratus anterior as secondary muscles.
What equipment do you need for the bosu ball balance single leg squat?
The bosu ball balance single leg squat uses bosu ball.
Is the bosu ball balance single leg squat good for beginners?
The bosu ball balance single leg squat is rated advanced. Build a base with simpler variations first, then progress to it with light load and strict form.

Related exercises

  • Band DeadliftBeginner · calves, glutes, hamstrings, quadriceps, and trapezius
  • Barbell Hang Clean Below The KneesAdvanced · calves, glutes, hamstrings, quadriceps, and trapezius
  • Barbell Mixed Grip DeadliftIntermediate · calves, glutes, hamstrings, quadriceps, and trapezius
  • Barbell SnatchAdvanced · adductors, calves, deltoids, erector spinae, glutes, hamstrings, lats, and quadriceps

Train it with Crucible Fit.

Every movement in this library is in the app with video and instructions, ready for your own sessions on the days between Crucibles. Your first Crucible is on us.

Download on the App StoreGet it on Google Play

See how a Crucible works