Squats are by far the best workout that you can do. I remember hearing from a personal trainer one time that if they were stranded on an island and they could only pick one workout to do, it would be squats.

Definitely a useful article; leg training and lower body exercises in general need more exposure.

One thing though, aside from sprints, can you mention some more non-equipment quad exercises that are also noteworthy? People who want to get into fitness for the first time tend to be somewhat intimidated because they lack equipment, so mentioning body weight (or otherwise) training for lower body would help that.

Yeah here you go - 10 sets of tabata squats holding the down position (thighs parallel with floor) during the 10 second rest interval between the first 5 sets.

Do that, then try to walk down a flight of stairs.