Bent & Straight-Leg Jackknife

How to: Bent & Straight-Leg Jackknife

Primary Muscles Used:Abs, Rectus Abdominis

Exercise Families:Trunk Flexion

Trainer:Kayla Itsines

1. Start by lying straight on your back on a yoga mat with your legs extended out in front of you and your arms extended above your head. Engage your abdominal muscles by drawing your belly button in towards your spine and elevate your legs off the mat slightly. This is your starting position.
2. Inhale. Exhale. Bend your knees and using your abdominals, draw them in towards your chest, ensuring that your feet stay together. At the same time, bring your hands forward towards your feet, slowly lifting your head, shoulder blades and torso off the mat.
3. Inhale. Slowly lower your arms and extend your legs to return to the starting position, but without lowering your feet to the floor.
4. Exhale. While keeping your legs extended, slowly raise your legs upwards until they form a 90-degree angle with your hips. At the same time, bring your hands forward and upward towards your feet, slowly lifting your head, shoulder blades and torso off the mat.
5. Inhale. Slowly lower your arms and legs to return to the starting position, but without lowering your feet to the floor. You should feel tension in your core throughout the movement. Continue alternating between bent- and straight-leg jackknifes for the specified number of repetitions. Each jackknife is equivalent to one repetition.