Wipers

Hang from a pull up bar and position yourself in a horizontal L - lean back so your back is close to parallel to the floor and hold your legs upwards, so they’re pointing towards the sky. From here, rotate your legs from one side and then the other, in a similar motion to windscreen wipers. Keep your body as still as possible and have your abs do the work.

There’s a short video demonstrating this exercise on this page. For more resources to help your calisthenics journey, check out courses here.