Performing the: A Step-by-Step Tutorial Band jack knife sit up
As you start to sit up, bend your knees and pull your legs towards your chest.
At the same time, bring the resistance band over your head and towards your knees, keeping your arms straight.
Hold this position for a second, making sure to engage your abdominal muscles.
Slowly lower yourself back to the starting position, stretching your arms and legs out, and repeat the exercise for your desired number of repetitions.