My husband and I have both been using these cords for about a month. We both love them as they are so easy to use and you can bring them anywhere. He did a workout at a trailhead the other day. We have purchased a couple of videos to learn more exercises. There are very good but basic ones described in the enclosed booklet to get you started. They look well made, but I think you should inspect them periodically to make sure your shoes haven't damaged them during workouts. We camp a lot during the summer and these will definately go along on every trip. You can do stretching, strength training and use them in an aerobic routine and feel them working. Can't go wrong with these!