Knee injury a year ago
About a year ago, I decided to get a really hard workout by riding my mountain bike (on roads with slight inclines) for 20 minutes straight - I didn't work up to it at all (but I'm young and invincible, of course). Afterwards, my left knee began hurting. Every time I ride my bike or go up stairs, it aggravates my knee. The pain is just above my knee cap down inside my knee a little bit. Is this my ACL likely? Can I rehabilitate it without surgery? I have found that when I jog my knee feels a lot better for the rest of the day.
By the way, I'm young - 21.