The Brute Force workouts keep my body guessing on what is going to happen to it every day. The workouts given by email or on the app are outstanding and do not take a tremendous amount of time out of the day. My body is sore after every workout because the Brute Force bags I have are filled with different amounts of sand and also have the insertable filler (lead shot) bags to shift the weight while working out. I truly enjoy working out using the workouts provided and at 51 yrs of age, I need the workouts to maintain lean muscle mass, balance and a strong core.