4. Barbell Windshield Wiper
Start lying on the ground holding a barbell up as you would for a bench press. Bring your legs up and then lower them to one side of the body – the straighter your legs the harder the move becomes.
An alternative would be to lower your legs down straight and then, as you bring them back up, rotate towards one side of the barbell.
This is a great exercise because it forces your upper body to stabilise against a load while activating your lower half.
The weight you put on the barbell will depend on your level of fitness.