As far as traditional cardio goes, it's all well and good, but HIIT (High Intensity Interval Training) can take less time and be more effective because of an effect known as the "after burn effect." A lot of bodybuilding enthusiasts use it to stay lean and shredded. Anyways, this is the android forums so let's keep this Android related. If you do HIIT, do you use an app? If so, which one(s)?