Although adding extra weight to your gait can help you subtract more calories, using dumbbells can strain the joints and who owns a weighted vest? Grab a medicine ball instead and hug it to your chest as you run. Having the additional pounds at your core where your body can handle it is safer than holding dumbbells and "because your arms are wrapped around the ball, you can't use them for momentum, which puts more stress on your legs to do the work, especially if you sprint,” Ryan says.
Try her Protect the Cargo Cardio Drills routine, a mix of 2-minute walks and 45-second sprints that zaps more than 300 calories in 25 minutes. (This works even better if you can preprogram your intervals on your treadmill so you don’t have to fumble with the buttons.) Aim to complete the workout without setting the ball down, but if you get tired, rest it on the treadmill console.