How to do it
- Lie on your back with your arms straight up over your shoulders and your hips and knees bent to 90 degrees.
- Press your lower back into the floor.
- Slowly extend one leg and the opposite arm, stopping just short of the floor.
- Return to the start under control.
- Repeat on the other side.
Key cues
- Low back stays on the floor
- Move slowly
- Stop just above the floor
- Other limbs hold still
- Leg straightens fully
Common mistakes
- Letting the lower back arch off the floor
- Moving too fast
- Touching your heel or hand to the floor
- Letting the still arm and leg drift
Muscles worked
- Primary
- Abs
- Secondary
- Obliques
Equipment
Exercise mat.