@Perry --- Hi! My extension is 0 in both legs and flexion is 135 in both legs so Yes, I can ride a real bicycle. I live near stores and gyms so if there is no threat of rain, I ride a bicycle to go pick up little things from the grocery stores, etc. And I teach yoga for a living so I plan to go back to teaching in another 7 weeks which will be a full 4 months from my bilateral total knee replacements. Well, I said "PLAN" it may not happen. I may not be well enough to resume teaching yoga in which case I will simply have to wait a bit longer. As you may have read on Bonesmart---The knees dictate what we can and cannot do.
There are so many on this Forum who know so much more than I do so I hesitate to give advice but this is what I found to have worked for me to gain more Range of Motion. Here's what I do to quickly gain extension and flexion:
1) Relax first, don't worry about what the knees will let me do or not. Consider watching a comedy, a funny video on You Tube, read a joke from the internet, play with your pets, whatever gets you in a relaxed and happy mood. Do this first because it naturally loosens your body all over. Tightness dissipates on its own from your feeling good and happy. If you can laugh, all the better. That really loosens you up.
2) Then just do heel slides but the first few reps, don't go to the point of pain or tightness, just do what feels comfortable but do slide the heels back and forth to get the motion going.
3) Then slide the heel to the point where you feel tight. Then HOLD it there. Don't push past that point of tightness. Just stay there where you first feel that hint of tightness and breathe in and out comfortable for 15 or 20 whole breaths then straighten your legs and really exhale. Relax for a few breaths. Then slide your heel toward your buttock again to the point of tightness and breathe for 15 or so breaths again. You will find that that point of tightness gradually shifts gently painlessly and your foot will get closer and closer to your buttocks and you gain so much more flexion without frustration or pain. The key is to only go to the point of tightness. Be kind to yourself don't push past that. The body will start to learn to feel comfortable at that degree of tightness while you relax and breathe all those breaths. Then that point of tightness will keep progressing where you gain more flexion. The body relaxes if it can trust that you won't do anything to hurt it. If you push to the point of pain, the body's natural tendency is to contract the muscles, tighten up to protect itself from "harm!" And you will not gain ROM (Range of Motion).
All of the above I use when I teach my yoga classes. Gradual, relaxed, and kind to the body. After a while, you'll be amazed at what the body will allow you to do.
I am sorry you did not sleep well. Sleep was a challenge for me for many many weeks. Stay happy. I am sorry if I seem preachy. Do not mean to but this is why we go on Bonesmart, right? To learn from one another and help one another through this journey.
Please smile, laugh, and have a good day in spite of all that you are going through. My thoughts and prayers are with your recovery.