How to do it
- Lie on your back with your arms by your sides, or your hands under your hips for support.
- Press your lower back into the mat and, if you can, lift your head and shoulders with your chin tucked.
- Lift your straight legs a few inches off the floor.
- Kick them alternately up and down in a small range, at a steady pace.
- Keep going for the set, stopping if your lower back starts to arch.
Key cues
- Lower back pressed into the mat
- Legs straight
- Small, steady kicks
- Feel it in your abs, not your hips
- Chin tucked
Common mistakes
- Letting the lower back arch off the floor
- Lowering the legs further than your back can stay flat
- Letting the hip flexors do the work instead of the abs
Muscles worked
- Primary
- Abs
- Secondary
- Obliques and hip flexors
Equipment
Exercise mat.