P90X is an intensive 90-day home fitness program that combines a variety of exercise styles, including strength training, cardio, yoga, plyometrics, and stretching. Most of the workouts are just under an hour in length, and feature Tony Horton as instructor and motivational leader along with 3 or 4 fellow exercisers as backup. For workouts that require weights, one of the backup exercisers will generally demonstrate the exercise using the alternative resistance bands. The backup exercisers also demonstrate some moves at lower levels of intensity for participants who aren't as fit. With the exception of the Ab Ripper X routine, each workout generally begins with about a 10 minutes dynamic warm-up and ends with a cool-down of 3–5 minutes.