Core · Resistance Band
Band Jackknife Sit-up
How to do the band jackknife sit-up, the muscles it works, and the mistakes to avoid. Pulled straight from the Kovo app's exercise library.
- Equipment
- Resistance Band
- Difficulty
- Intermediate
- Logged as
- Weighted reps
- Movement
- Flexion
- Mechanic
- Isolation
How to do it
Anchor a resistance band low behind your head and lie on your back holding the band overhead with both hands, legs extended. In one motion, sit up while lifting your straight legs toward your hands so your body folds into a V, pulling the band as you crunch. Lower back down under control and repeat.
- 1Your upper abs crunching hard as your torso and legs meet in the middle
- 2The band adding resistance as you fold up into the V
- 3Hip flexors helping draw your legs up toward your hands
Common mistakes
- Yanking with your arms instead of crunching with your abs
- Letting your lower back slam down on the return
- Bending your knees heavily to shorten the lever
Muscles worked
The band jackknife sit-up mainly works the upper abs and lower abs, with the hip flexors, obliques, and quads assisting.
- Upper AbsPrimary
- Lower AbsPrimary
- Hip FlexorsSupport
- ObliquesSupport
- QuadsSupport
- ForearmsMinor
- LatsMinor
- Front DeltsMinor
Kovo programs the band jackknife sit-up for you and tracks it every session.
We build your whole program, drop the right lifts into each workout, and adjust your weights as you get stronger. Free on iOS and Android.
More abs & core exercises
- How to do the ab wheel rollout
- How to do the ankle tap plank
- How to do the ankle taps
- How to do the resistance band dead bugs
- How to do the resistance band pallof press
- How to do the rollout
Last reviewed June 2026.