Q: What is the best cardio workout? Which one is more productive for burning, toning etc? Running, biking or jump roping.

A: For cardio I like HIIT (see near the end of my Fat Loss article). HIIT is an approach, not a specific exercise -- you can do HIIT on a treadmill, bike, swimming, jumping rope, etc. Whether you do HIIT or regular constant-pace cardio, I like swimming for cardio because it uses your whole body and has zero impact on your joints and bones (unlike, say, running). Biking, rollerblading, and jumping rope (when done properly) are also lower-impact choices compared to running.

In the end my advice for cardio is to do what you enjoy most and are most likely to stick with. Unless you're training for an endurance event, cardio should be the smaller part of your exercise program with weight training taking the bigger role since weight training is a much more effective fat-burner, and muscle-, bone-, and strength-builder. You shouldn't be running an hour every day (more like 2-3 hours/week max in a well-rounded program to lose fat) so even running shouldn't have any adverse effect on your joints. So pick whatever you enjoy and are most likely to stick with. And don't forget about the diet and weight training if you want best lasting results.