Window washers - with barbell (Lower trunk rotation strengthening, legs to ceiling, supine - with barbell)

Lie face up on a mat, holding a barbell directly above your shoulders.
Flex your hips to 45 degrees and fully extend your legs up towards the ceiling.
Keeping your back on the floor, lower your legs to the side so that they touch the floor at approximately 90 degrees to the body.
Return to the starting position and repeat on the opposite side.