เรื่อง: Zumba is a good workout with an instructor. Sun Aug 01, 2010 11:58 pm
"""Jillian Michaels is using a very effective approach to weight loss: interval training. If you train as hard as you can for a minute or two, and then take the level down for a few minutes, and then back up again--your body will default to the higher calorie burning level. (Maybe we really are running from a sabertooth tiger. Let's keep it up.)