What are the best activities to do on zwift to recover from bilateral knee replacement. I recently purchased a smart trainer and dont want to over do it but certainly am ready to do hour long rides. Any suggestions. Thanks
Ask your doctor or a physio to make sure it is wise first!
But, being the owner of dodgy knees, I generally try and keep the force going through them low - either higher cadence or just go slower. I think longer is better than more intense.
Keep seated.
I’d also pay close attention to the geometry of your pedals and leg extensions, saddle/handlebar position to make sure none of the angles are causing unusual strains. If possible a bike fit with a professional would help here.
Stick to the flat routes, or change your trainer difficulty to 0 (all the way to the left) to make all roads flat. Or try making a custom workout with a low wattage target using ERG mode to control the resistance of the trainer. Of course, talk to your PT and Doc to make sure you aren’t over doing it.
Thanks for suggestion. I will try to do rides with least amount of elevation and keep work load at 100 watts to start. Does that sound good
Depends on what your FTP is, 100 watts could be too much or not enough? Ultimately, you need to ask your Doc. Don’t take medical advice from random zwift fanatics on the internet! 
I am not a doctor and don’t take any of what I say to replace sound medical advice from your doctor and/or physical therapist. But I had meniscus surgery at the beginning of the month and for my rehab they had me get back on the bike pretty quickly. I am however allowed no resistance (trainer difficulty at 0%). It’s more about getting the range of motion back in the leg.
I started off in the granny gear (small front big back) and slowly increasing my cadence (first few days I was lucky to get 20rpm). But after a few weeks I’m back to 80-90 easily and can go a few gears faster. I was also given time limits (5-10 min the first time) and allowed to increase by a few minutes each time I rode (assuming I didn’t have any pain). I used to ride 90 minutes easy pre-surgery but 3 weeks post-op and I’m only at 40 minutes. You don’t want to jump in to an hour long session right away.
Big thing is don’t overdo it as you don’t want a set back. I’d definitely speak with your Dr/Physical Therapist and let them know what you’d like to do and have them create a plan for you. Best of luck on the rehab.
Thanks for feedback
I will set trainer difficulty to 0 and go from there
It’s 2.5 years on now (same as my left knee replacement 62yo) - I set up today with Schwinn IC8 …… will start lowest of lower 0 and flats. Hills and resistance could kill my motivation.