The truth is you really don't need a lot, if any weight, to do an effective leg workout. All you need is the right exercises and you can build legs that look and are in dramatically better shape than any number of squats will do for you.
The mention of yoga brings to mind a set of physical exercises with a flavor of India. However, yoga can be much more than a regular workout routine. Yoga may also involve mental and spiritual disciplines to encourage an overall sense of wellbeing.