How long does it take for a 1 year old to heal from a leg injury?

Depends : Since I do not know the type of injury, i can't give you specific estimates, but broken bones take on average 6-8 weeks to heal, muscle pulls, ligament, tendon injuries, sometimes as long or longer. Bruises can take a few weeks depending on their depth and lacerations can take as long as a year for the skin to reach equal strength as before although the wound may look normal.