Instructions:

1. Lie flat on your back with your knees bent and feet flat on the ground.
2. Place your hands behind your head with your elbows pointing outwards.
3. Engage your abs and lift your upper body off the ground, bringing your right elbow towards your left knee.
4. At the same time, extend your right leg straight out and lift it off the ground.
5. Pause for a moment, then return to the starting position.
6. Repeat the movement, this time bringing your left elbow towards your right knee and extending your left leg.
7. Continue alternating sides for the desired number of repetitions.