We reviewed Tracy Anderson's Dance Cardio DVD a few weeks ago - here's the 411 on Anderson's Mat Workout DVD ($30). Anderson maintains a steady pace and the workout, while taxing, is easy to follow and effective. She goes through a series of leg, ab, and arm exercises geared to engage your accessory muscles and exhaust larger muscle groups. You may feel a bit ridiculous during the "arm dancing" section ... until your arms feel like they're burning with the heat of a thousand suns.The first week or so you will ache in places you didn't know you could ache, but not in an unbearable way. The warm-up and cool-down sections at the beginning and end are tempting to skip for the sake of saving time, but your body will rebel if you do. Done back to back the whole workout - cardio and mat - runs just under 2 hours. If you can swing doing them in conjunction at least 4 times a week you will see legitimate results.