thanks for the info..im actually gonna start sprinting now...what kind of sprints do you recommend?? and for a total of how many minutes on the treadmill.. But how does blood rate figure into this?? If your sprinting rather than jogging..doesn't your blood rate go high and then into the cardio zone (burning fat & muscle) as opposed to staying in the fat burning zone with just a light jog for 45 minutes?? I also want to hear rackhams response..i have a feeling he will disagree. I think the best way to cut up is just eat sensibly..