I was diagnosed with Achilles tendinitis a couple of years and never let it stop me being on a bike. It did sometimes slow me down though. Last year I got a new podiatrist and he found that my AT was being shredded by bone growth on my heel. Surgery to repair the tendon September, and today I am 75% healed with a few rides under my belt this year. FWIW, I was given some inserts for my shoes that did help with the pain a bit.