A pendulum is a swinging weight that swings back and forth in a pendulum clock to keep the time. And exactly with this swinging movement I will train my lateral abdominals today.
I lay down on my back and lift my legs straight up in the air. Then I start to swing my legs first to the left stopping right before touching the floor and then I bring them to to the right side; like the reversed pendulum of a clock. But I’m quite sure that that one will swing longer than my legs.
I wish you a good swinging!