P90X has ranked as one of the most popular home fitness programs in America since its release in 2005. The intense 90-day program is primarily aimed at increasing overall fitness and burning fat, but it also builds lean muscle mass. The P90X website features success stories from skinny guys who gained muscle with the program. In addition, a study on the efficacy of the P90X program by the American Council on Exercise concluded that it's effective for building muscle.
Read more: Is P90x a Good Workout for Beginners?
Muscle Building and the P90X Program
Your muscles increase in size in response to stress. When you lift weights, you cause tiny tears in the muscles that must be repaired. During the healing process, the muscles grow stronger and bigger. Your body type determines how easily you put on mass; skinny guys, or ectomorphs, have the hardest time building muscle but with the right training program -- and a proper diet -- it's possible.
P90X includes a lot of strength training, so there is plenty of opportunity to stress the muscles to get results. At the core of the program is the concept of "muscle confusion." Varying your workouts keeps your body from reaching a plateau because it never adapts to the exercise routine. This can be an advantage for skinny guys who have difficulty gaining muscle.
Training for Skinny Guys
To build mass you have to stress the muscles, which means lifting as much weight as you can. The general rule of thumb for hypertrophy, or muscle-building, is to do sets of between eight and 12 reps to muscle failure. This means lifting enough weight that you cannot possibly do another rep with good form after the 12th rep.
This will be up to you to determine when you are choosing your weights for each exercise. A good goal is to shoot for 10 reps to muscle failure on each set. Make sure you have the right size dumbbells that allow you to work to your limits and allow you to continue to go up in weight as you become stronger.
There are also a lot of body weight exercises in the program, such as plyometrics and pull-ups. Once you are strong enough, these can be manipulated to your advantage by adding weight. Before you do this, however, you need to be able to do full sets of the exercises without weight. Then, you can add resistance in the form of ankle weights, resistance bands and a weight vest.
Scale Back the Cardio
Cardio is an important part of any fitness program. It strengthens your heart and lungs and helps keep fat off when you're eating more calories. However, skinny guys trying to gain mass don't need to do as much as the P90X program includes.
If you're lifting heavy enough, you will need extra recovery time. During recovery is when your muscles repair and grow. You can substitute an extra rest day or stretch session each week for one of the cardio sessions.
To build muscle you have to be consistent. Don't skip your workout. The variety built into P90X cuts the risk of boredom, which might help you stick with the 90-day program and have it work for you. In each session, work as hard as you can. Lifting heavy enough weight at a high intensity will lead to hypertrophy.
To build muscle with this intense workout, you'll have to eat enough to fuel your workouts and support muscle growth. Don't skip meals during the program, and eat enough lean protein to give your muscles the raw materials they need.
Read more: What Equipment Is Needed for P90X Workouts?