Description

The jackknife sit-up is an advanced abdominal exercise that targets the rectus abdominis for core strength and stability.

Starting Position

Lie flat on your back with arms extended overhead, legs straight, and feet slightly off the ground.

Technical Execution

Exhale as you raise your upper body and legs towards each other, forming a V shape, then lower back down with control.

Range of Motion

The range of motion should involve bringing the upper body and legs together as close as possible, then returning to the starting position.

Variations

Variations include bent-knee jackknife sit-ups or adding a twist at the top for oblique engagement.

Common Mistakes

Common mistakes include using momentum to swing the legs, straining the neck, and not engaging the core muscles properly.

Practical Advice

To perform the jackknife sit-up correctly, focus on controlled movements, engage the core throughout, and breathe steadily.

Additional Notes

This exercise requires good flexibility in the hamstrings and hip flexors to achieve the full range of motion.

Difficulty Level

Advanced

Equipment Needed

Body Weight

Primary Muscles

abdominals

Secondary Muscles