I was diagnosed with chondromalacia patella. how long should i rest before walking(for exercise)again? is biking good for this? my doctor said it was?

Chondromalacia: Yes, absolutely. Training your thigh muscles evenly if the best treatment and biking does this very well.

Patella: Ok to progress as tolerated. Consider biking with seat elevated, swim, walk, yoga, pilates.

Variable rest: Treatment consists of activity modification, ice, anti-inflammatory meds and therapy aimed at flexibility and strengthening, especially of your core. Depending upon severity, you may need to rest for a few wks before starting therapy. Cycling is good too.