If you’re sick of crunches and planks, we hear you.
Add variety to your exercise routine and try jackknife sit-ups – but be prepared for a challenge.
Because working your core muscles has so many health benefits—like achieving a flatter stomach—many of us don’t get enough core exercise.
Jackknife sit-ups (or V-ups) are popular now because you only need your body and a mat to perform them. That’s right, no fancy tools needed!
Jackknife sit-ups are beginner-friendly, low-impact, and can help build your abdominal muscles (rectus abdominis).
Also, there are plenty of ways to modify and increase the intensity of these exercises. So, get ready to shred your six-pack.
Jackknife Sit-Up: Step-by-Step Instructions
Follow these steps to increase your core strength. Floor or carpet burns are the worst, so grab a mat to cushion your spine before you start.
- Lengthen your body on your mat. Lie flat on your back and keep your lower back neutral (avoid a rounded or arched spine).
- Extend your legs long and reach your arms above your head.
- Rotate your arms and legs a few inches off the mat (yet pressing your tailbone into the mat).
- Take a deep breath, and on your exhale lift your head and pull your arms and legs into a V-shape (raise about 30-45 degrees away from the mat).
- In your lift, keep your legs straight and your arms parallel to your thighs.
- Lower down to your starting position.
- Repeat these steps for 10 to 12 repetitions and 2 to 3 sets.
How to make jackknife sit-ups easier
We understand that this exercise is difficult. Build up the burn with these simple variations that will still shake your muscles.
- Try single-leg jackknife sit-ups, alternately lifting one leg.
- Work through jackknife sit-ups with bent elbows and knees instead of straight arms and legs.
How to make jackknife sit-ups harder
Now that you’ve worked through the basics of the jackknife sit-up, we’ve come up with some ideas that can help you up the challenge and add some flair.
- Hold a weight (dumbbell, medicine ball or weight plate) in your hands! The added weight will definitely help jack up your jackknife intensity.
Benefits of Jackknife Sit-ups
“Put down the jackknife and take direct aim [abdominals] and strengthens the entire core,” explains Alexa Cohen, personal trainer at Crunch Union Square in New York City.
With a strong core, you may have more endurance for your other favorite activities.
Jackknife Exercise Alternative
Perhaps you’ve mastered the jackknife sit-up, and you’re looking to expand your horizons. Here are jackknife sit-up exercise options for you to try.
Side jackknife sit-up
- Come to your side and bend your bottom elbow to 90 degrees.
- Press your hips into the mat and lengthen your legs. Bend your upper arms and place your hands behind your head.
- Crunch your elbows into your hips to engage your oblique muscles. Simultaneously lift your upper leg towards the ceiling.
Stability ball jackknife
- From a high plank position with your hands under your shoulders, lift your hips into the air and place your feet on a stability ball.
- Contract your abdominal muscles to close the distance between your chest and balls.
- Keep your hips down and push the ball forward on the contraction.