I highly recommend cycling!
I ripped apart my thigh muscle in an accident when I was nine. It healed nicely but my leg was very weak, I had pain and a limp. Any instructor could tell as soon as I got on a horse that I had a previous injury.
Started cycling daily 2 years ago and the change in my leg has been amazing, no pain, no limp, no weakness or collapsing whatsoever. My last instructor said my weak leg was actually my injury free leg!
My leg was even strong enough to start running and I did a half marathon last summer and did some 100 mile bike rides,all pain free.