The Plank Pull through will work your hip flexors, obliques, lower back and shoulders as well as particularly challenging your abdominal muscles.
Set yourself up in a press up position with your feet slightly wider than usual and a weight just outside and behind you right wrist. From here, reach your left hand across under your body grabbing the weight, lifting and pulling it across placing it back down in the equivalent position on the other side of your body.
Throughout this exercise you should be thinking about trying to minimise any rocking in our hips that may occur when you reach across or pull through. If you are finding that you are rocking a significant amount, you can try pulling the weight less far across your body, or using a lighter weight.