I got the NAC System's Interval Challenge about four months ago and have been working out to it religiously three times a week. It is by far the best interval tape I have ever done. Then I found the Measured Intensity tape and I now do it two times a week. I take one day off and either run or walk on the remaining day of the week (to get outdoors). I have seen results and feel very energized after every workout because the instructors are very motivating. I have just purchased the Body Parts tape, but I have not done it yet. I will write a review after I complete it - but if it is anything like the other two I am sure it will be great. I am a NAC believer!

Instructor Comments:

The instructors are fun, full of energy and motivating. They know what they are doing and seem like down to earth real instructors. There are five of them and they switch off so you never get tired of hearing or seeing any one of them like you do in other videos.

Jerri L.