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Jack Knife

What it does?

The 'jackknife' is an advanced exercise for the abdominals which focuses on the core stabilisers and lower abs

What you need?

A swiss/gym ball

How do you do it?

- Get yourself into a press-up position with your shins or feet resting on the top of a swiss ball
- Lift your bum up slightly for good posture
- From this position, begin to pull the ball in towards your body by driving your knees towards your chest
- Pause briefly at the end of range then extend your legs to return the ball to the start position
- Use a tempo of 2-3 seconds in, 2-3 seconds out
- Repeat 8-10 times and do 3 sets

Key Points

- Control the movement with your abdominal muscles whilst performing the movement
- Prevent your back from sinking by using your abs



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