How to do the Jackknife, step by step
- Lie flat on your back, arms overhead.
- Raise your arms and legs at the same time.
- Bring your hands to your feet in the middle.
- Lower back down under control.
Common mistakes and how to fix them
- Legs bendkeep them straight, or tuck your knees as an easier version.
- Dropping downlower slowly.
How to scale the Jackknife
If you can't do the movement cleanly yet or the workout is too heavy, use one of these variations:
- V-up with bent knees
- Crunch
Also known as
Jack knife
These descriptions are general guidance and don't replace a coach. Have someone at your box show you new movements, and stop if anything hurts.