Why does it take soo long to recover from a ACL injury? My doc tells me 9 months before playing football.?

you really should not play anything for 9 months like your doctor said or longer. your acl injury will come back to haunt you in about 12 years. an acl injury is a tear in your knee, and like all tears they take a very long time to recover themselves back to somewhat normal. if you want to heal as fast and best as possible really follow your physical therapy and be committed. only you can make yourself better at this point.