IMO, bike will be fine as long as you do it at a level that gets your heart rate in the area where it would be on a treadmill. Following this, once your ankle starts feeling a little better, I would use an elliptical machine as it doesnt appear IMO to have as much stress as a treadmill.
Then finally go back to the treadmill.
__________________ Strength is understanding that your power is both physical and emotional. - Henry Rollins |