Exercise guide
90 To 90
- Beginner
- Compound
- Rep-based
- Lower legs
- Upper legs
- Waist
The 90-90 rotation is a foundational mobility and core exercise that improves hip internal and external rotation while activating the obliques and glutes. It is highly effective for opening up the hips and building functional rotational stability.
Reviewed by the Crucible team · Updated June 2026
Muscles worked
Setup
- Sit on the floor with your knees bent and feet flat, positioned wider than shoulder-width apart.
- Place your hands on the floor behind your hips for support, leaning back slightly to maintain a tall spine.
- Flex your feet toward your shins to protect your knee joints throughout the movement.
How to do it
- Exhale and slowly rotate both knees to the right, aiming to touch the floor with the outside of your right leg and the inside of your left leg.
- Inhale as you rotate your knees back through the center starting position.
- Exhale and repeat the movement to the left side, maintaining a slow and controlled tempo.
- Focus on moving through the hips rather than just shifting your weight side to side.
Form checklist
- Maintain a 90-degree angle at both the front and back knee during the rotation.
- Keep your chest lifted and avoid slouching or rounding your lower back.
- Ensure your feet stay in their wide stance and don't slide closer together.
- Keep your sit bones as close to the floor as possible during the transition.
Pro tips
- Think about 'prying' your hips open by driving the trailing knee toward the floor to maximize internal rotation.
- Engage your obliques to control the descent of your knees rather than letting gravity pull them down.
Make it harder
- Remove your hand support and hold your arms out in front of your chest to force the core to stabilize the torso.
- At the end of the rotation, drive your hips forward and upward into a tall kneeling position to further engage the glutes.
Frequently asked
- What muscles does the 90 to 90 work?
- The 90 to 90 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?
- The 90 to 90 requires no equipment — just your body weight.
- Is the 90 to 90 good for beginners?
- Yes. The 90 to 90 is a beginner-friendly movement and a strong foundation to build on.
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