Grab a towel or pillow on a comfy surface to support your forearm to try a side bend lift.
You'll want your shoulder directly above your elbow. Your top arm's hand can hold onto the lower forearm for support. Then lie sideways on one hip with your legs in a straight line.
Beginners can put one foot in front the other to advance it, stack one foot on top of the other or leave the top leg up in the air.
Tense your stomach muscles like a fist, push into your forearm and bottom foot and lift your hip to the ceiling and then back down again. You'll also want to make sure your head is not leaning on your shoulder. If you want to work harder, take your top arm to the ceiling.
Try to see how many times you can lift and lower in 60 seconds. Then roll on over to the other side.