This is more of an endurance type of workout. It will also raise your heart rate giving you cardio benefits. It's absolutely challenging, however, I have workout DVDs that focus more on building strength. I also have better endurance types of workouts I prefer over this one. One of the individuals in this workout uses a weight that is obviously too heavy for her and causes her to practice poor form, which Bob does not correct. That is a poor example for people using this DVD who may not know better.