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  3. Exercises
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  5. Core & Abs
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  7. 90 To 90 Switch

Exercise guide

90 To 90 Switch

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

The 90/90 switch is a dynamic mobility and stability exercise that improves hip internal and external rotation while engaging the core and glutes to stabilize the pelvis.

Reviewed by the Crucible Fit team · Updated June 2026

Watch the 90 To 90 Switch demonstrationVideo and instructions for every movement are in the Crucible Fit app.

Muscles worked

Primary

  • Abs
  • Glutes
  • Obliques
  • Quadriceps

Secondary

  • Hip flexors

Equipment

  • Body weight

Setup

  1. Sit on the floor with your front leg bent at a 90-degree angle in front of you, shin parallel to your chest.
  2. Position your back leg out to the side, also bent at a 90-degree angle, with the knee aligned with your hip.
  3. Sit tall with your torso upright; place your hands on the floor behind you for support if needed.

How to do it

  1. Inhale to brace your core, then lift both knees off the floor while keeping your heels pinned to the ground.
  2. Rotate your hips through the center, pivoting on your heels until your legs reach the opposite 90/90 position.
  3. Exhale as you lower your knees to the floor on the new side, ensuring both knees maintain their 90-degree angles.
  4. Repeat the movement in the opposite direction, alternating sides with a slow, controlled tempo.

Form checklist

  • Keep your chest lifted and avoid rounding your lower back.
  • Maintain a 90-degree angle at both the knees and the hips.
  • Keep your heels in contact with the floor throughout the entire rotation.
  • Minimize torso leaning by using your obliques to stay upright.

Pro tips

  • At the end of the switch, actively drive the trailing knee into the floor to maximize internal rotation and glute engagement.
  • Imagine your pelvis is a bowl of water; try to keep it level as you rotate to maximize hip isolation.

Make it harder

  • Perform the switches with your hands off the floor (arms crossed or reaching forward) to increase core and hip demand.
  • Add a hip extension by driving your hips forward into a tall kneeling position once you reach the end of each switch.

Frequently asked

What muscles does the 90 to 90 switch work?
The 90 to 90 switch primarily targets the abs, glutes, obliques, and quadriceps, and also works the hip flexors as secondary muscles.
What equipment do you need for the 90 to 90 switch?
The 90 to 90 switch requires no equipment — just your body weight.
Is the 90 to 90 switch good for beginners?
The 90 to 90 switch is rated intermediate. Build a base with simpler variations first, then progress to it with light load and strict form.

Related exercises

  • 90 To 90Beginner · abs, glutes, obliques, and quadriceps
  • Barbell Lunge TwistIntermediate · abs, glutes, hamstrings, obliques, and quadriceps
  • Bosu Ball Step-Up High Knee Air TwistIntermediate · abs, calves, glutes, hamstrings, obliques, and quadriceps
  • BrettzelIntermediate · abs, glutes, obliques, 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.

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