Abs · Body weight · Intermediate
How to do Jackknife Sit-up
The jackknife sit-up is a bodyweight exercise targeting the abdominal muscles. It involves simultaneously lifting the legs and upper body to meet in the middle, engaging the core and hip flexors.
- Primary muscle
- Abs
- Also works
- Hip flexors
- Equipment
- Body weight
- Level
- Intermediate
- Category
- Abs
How to do Jackknife Sit-up, step by step
- Lie flat on your back with your legs extended and your arms overhead.
- Engage your core and lift your legs and upper body simultaneously, reaching your hands towards your toes.
- Pause for a moment at the top, then slowly lower your legs and upper body back down to the starting position.
- Repeat for the desired number of repetitions.
Station taken, or training at home? Alternatives to Jackknife Sit-up →
Muscles worked
Jackknife Sit-up works your abs as the main mover, with help from your hip flexors.
Track Jackknife Sit-up in SPLYT
Jackknife Sit-up is already in SPLYT’s exercise library. Log your sets, reps and weight on iPhone or Apple Watch, with last time’s weights already filled in.
