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Jack knife on Ball

Jack knife on Ball

The Jack knife on Ball is a fantastic exercise that targets your core muscles, particularly the rectus abdominis (your "six-pack" muscles), obliques, and hip flexors. This exercise is performed on a stability ball, which adds an extra challenge by engaging your balance and stability muscles. By lying on your back with your hands stretched overhead and your legs extended, you begin the movement by crunching your body into a V-shape. Simultaneously, you raise your legs off the ground while reaching your hands towards your feet. The exercise is named "Jack knife" because your body resembles the shape of a folding jack knife at the peak of the movement. The Jack knife on Ball is a multi-joint exercise that involves both flexion of the trunk and flexion of the hips. This combination creates a highly effective workout for your abs and hip flexors. Additionally, the instability provided by the ball further engages your deep core muscles, improving your overall balance and stability. Adding the Jack knife on Ball to your workout routine can help strengthen your core muscles, enhance your posture, and improve your overall functional fitness. However, it is important to perform this exercise with proper form and ease into it gradually to avoid any potential strain or injury. With consistent practice, you'll be well on your way to achieving a stronger and more defined midsection.


  • Start by lying on your back on an exercise ball, with your feet flat on the floor and your arms extended above your head.
  • Engage your core and lift your upper body and legs off the ball, bringing them together towards the center of your body.
  • At the same time, try to touch your toes with your fingertips, forming a 'V' shape with your body.
  • Hold the position for a second and then slowly lower your body back to the starting position.
  • Repeat for the desired number of repetitions.

Tips & Tricks

  • Engage your core muscles throughout the exercise to maintain stability and control.
  • Start with a smaller range of motion and gradually increase as you build strength and stability.
  • Keep your gaze forward to maintain proper spinal alignment.
  • Exhale as you lift your upper body and inhale as you lower back down, focusing on controlled breathing.
  • Use your arms for balance and support, placing them on the sides of the ball.
  • Maintain a controlled and slow tempo for each repetition to maximize muscle activation.
  • Ensure the ball remains stable throughout the exercise by using a properly inflated ball.
  • Consider consulting with a fitness professional to learn proper form and technique for this advanced exercise.
  • Gradually increase the difficulty of the exercise by extending your arms overhead while performing the jackknife.
  • Perform a thorough warm-up prior to attempting the exercise to prepare your body for the movement.


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