Does anyone do or know those that do exercises going on each side.

Lifting each leg 25 time each? Done with one person or the individual themself.

It apparently improves rigidity.

One side to side exersise that helps me is laying in bed ...put arms straight down /palms down ..pull bent knees up as far as you can toward face (feet are off the bed)...then roll from side to side over your arms. Use the balance of your arms against the bed and use your muscles to turn back the other way. It is not easy at first, but it will also train your body for turning over in bed and getting out of bed... which so many people find difficult later on. You have to create new muscle memory You Can Do IT. Someone can help you at first to push your knees over and help you come back to the other side until your body learns what muscles to build up and use to accomplish this. Just having someone turn you back and forth in this way will loosen stiffness the whole way along your back. I started doing this exersise years ago in Florida when trying to strengthen my core to try to learn to flip a kayak. *Never got the kayak flipped over and back up, but I didn't have one that fit me snug so we could move as one...think I would have made it if fitted properly.

Just wanted to add to exercise...if you put your arms out to the side and use them as a brace and balancer...it is much easier at first (bendiing and straightening your elbows to help you boost your bent up legs to the other side of the bed. It can even help you to get up as you learn to use the momentum generated. When you are ready to get up...just swing your feet over the side and push up at the same time with the arm on that side of the bed. ..this will sit you up. You can also do this with hands around the underside of your bent up knees. Just keep you shoulders flat as possible on the bed while doing this so you are just turning at the waist. It will really improve torso strength