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Jackknife Sit Up
This is a much harder version of the vertical Leg crunch. You can vary the intensity by varying the legs. Straight leg is harder, and bent knee is easier. Also, arms extended over head is harder and the lower you have your arms becomes easier. Keep in mind that harder exercises tend to have a greater risk of injury. On this exercise, risk is to your back. Try to keep your spine from coming off the floor. If it does, bend your knees and limit how far down your legs go.
Benefits
Helps flex the spine and maintain control over abdominal muscles and helps stabilize your spine and pelvis.
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Body Parts Used
Main focus is on the rectus abdominus.
Instructions
- Lie on your back on a mat or floor.
- Extend your arms over our head and have legs extended straight.
- Exhale as you tighten your abs as you simultaneously bring your arms and legs up at the same time to touch together at the top. Analogous to closing a book with both hands.
- Inhale as you return to nearly the starting position. Stop just before touching down and repeat for as many repetitions as desired.
- To make it easier, bend your knees and lower your amrs. This decreases the amount of weight that must be lifted by decreasing the lever length.
Similar Exercises
Sample Routine
Go here to see samples of complete ab workout routines.
Note: One exercise alone is not sufficient for any goal. All exercises should be part of a comprehensive exercise program. Also, see my list of exercises for more.