Jackknife

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Purpose

Strengthens abdominal muscles, all stabilizers, and many other muscles.

Starting Position (Figure 1)

  • Roll out over the ball until your feet are on the ball.

  • Straighten your body as a rigid plank from head to toe.

  • Pull your abdominal muscles in.

  • Place your hands at the level of your shoulders, and a comfortable width apart.

Movement

  • Inhale.

  • Exhale and hold your breath as you hold your spine in perfect alignment and drop your knees straight to the floor.

  • The ball will roll towards you (Figure 2).

  • Inhale as you press the ball straight out behind you again.

 

Pace

3 seconds up

Do not hold

3 seconds down

 
 

Reps

Repeat 8-10 times

 
 

Sets

2

 
       
 

Tips

  • Do not lift your hips as you drop your knees.

  • Keep your body in perfect alignment.

  • Do not let your head drop or your lower back sag down.

  • Do not strain your neck or shoulders.

  • To increase the difficulty of this exercise, hold one leg straight out behind you as you do the exercise.

General Caution and Disclaimer

As with any exercise, always exercise caution.  If you have any concern about your ability to perform an exercise, consult your physician first.  If an exercise begins to hurt you in any way, discontinue the exercise immediately.

 

2008 Hydration Health & Fitness, LLC

 

 

 

Figure 1

Figure 2