Q: Hi Mike, Can I tone my legs with just doing cardio only (elliptical, bike, walking)? Or do I need to incorporate weights? Thanks!

A: Toning means different things to different people, but in general doing weights will help you. If you are overweight, then toning for you probably means losing some extra fat from your legs (most overweight people already have a fair amount of muscle on their legs -- it's just covered by fat). There's no way to target specifically leg fat, but by losing overall body fat you will lose the fat on the legs as well. And the best way to lose body fat is described here and it definitely does use weights in addition to cardio.

On the other hand if you have relatively skinny legs, then toning for you will mean building up some muscle and in this case weight training for legs through exercises like squats and lunges is the best way to go.

So in either case, doing resistance training for your legs is a good idea! If you really don't want to do weights for whatever reason, then at least consider doing very high intensity cardio, such as doing sprints or using cardio machines at high resistance and/or speed settings. This will have much of the same muscle-building effect as weights.