So you've got bad knees and can't do a lot of the good quad-focused lifts? You're not excused from leg day. One of the best knee-friendly quad-builders is cycling.

If you have access to an Airdyne or other fan bike, even better. These aren't just good for lung-burning interval work. They can give your quads every bit of the work you'd get from a traditional leg workout.

  1. On a scale of 1 to 10, with 10 being as heavy as you can move the pedals, crank the resistance up to a level pace that puts you around a 7.
  2. Pedal your feet and drive your arms as hard and as fast as you can for 15 to 45 seconds.
  3. Rest fully for 45 seconds to 3 minutes between intervals.

It's okay to lean forward during the intense portions of each interval. During the rest position you can stay seated or get off the bike and stand or pace around a bit before beginning your next work interval.

Related:  Get Ripped on the Rower

Related:  15 Quad-Building Exercises for Women