How to Do the Jackknife Sit-Up
💪 Abdominals🏋️ Body Only📊 Beginner🏷️ Strength
How to perform it
- Lie flat on the floor (or exercise mat) on your back with your arms extended straight back behind your head and your legs extended also. This will be your starting position.
- As you exhale, bend at the waist while simultaneously raising your legs and arms to meet in a jackknife position. Tip: The legs should be extended and lifted at approximately a 35-45 degree angle from the floor and the arms should be extended and parallel to your legs. The upper torso should be off the floor.
- While inhaling, lower your arms and legs back to the starting position.
- Repeat for the recommended amount of repetitions.
Muscles worked
The Jackknife Sit-Up primarily targets your Abdominals. You'll need body only.
Make it count toward your goal
Random sets rarely move the needle. In NYUS, the Jackknife Sit-Up slots into a plan built for your goal — sets, reps and progression auto-suggested, logged in two taps, and folded into a weekly review that adapts what comes next.