How to Do a Jack Knife Sit Up

Step-by-Step Guide

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   Step 1: Lie flat on the floor with your legs straight.

   At the peak of this step, you should be balancing only on your bottom.
   
   Your legs should be straight at about a 35-45˚ angle from the floor and your arms should be parallel to your legs. ,,, Lie with your stomach on the ball.
   
   Slowly walk your hands out until the ball is under your ankles. , Do not drop your hips or arch your back.
   
   Instead, tighten your abs to support your body. ,, Repeat until you've completed 2 to 3 sets. , In order to start seeing/feeling results, aim to do 2 to 3 sets 4 days a week for 6 weeks.
   
   For faster results, increase the number of sets/times per week you do this exercise.
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   Step 2: Extend your arms straight back behind your head.

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   Step 3: Exhale and as you do so

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   Step 4: raise both your arms and legs to meet at the top of the jackknife position.

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   Step 5: Inhale and lower your arms and legs to return to the starting position.

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   Step 6: Repeat.

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   Step 7: To make this exercise more challenging

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   Step 8: use an exercise ball.

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   Step 9: Exhale and bend at the knees to bring the ball in towards your torso.

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    Step 10: Inhale and straighten your legs to return to the starting position.

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    Step 11: Do 10 to 12 repetitions of this exercise per set.

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    Step 12: Keep it up over time.

Detailed Guide

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