Turn the negative into a positive. This could be a good chance to try some unconventional exercises or training methods.
Add weights or something heavy to a back pack. Go to a high school track and do 1 set long stride lunges for 30 reps, take the back pack off, do a HIT 40 yard dash, back to the back pack, and do 30 reps of deep knee bend lunges.
4 sets of these will fry your legs.