Most people will gain some size during the program simply due to the challenges placed on the muscles. The P90X workout is highly effective for total-body conditioning. On the flip side, if you find the workout so difficult that you're only able to complete one to six reps per set, you are not in the optimal range for building mass. Others will find P90X more challenging and may only be able to perform eight to 12 reps per set. Therefore, your reps will exceed the target range for hypertrophy. You may be able to complete close to 20 repetitions of an exercise during this amount of time. While you may only be able to complete eight to 12 reps of the harder exercises, you'll likely be able to complete more than 12 of the easier exercises. Each set of the P90X chest exercises are completed for about 60 seconds. This largely depends on your current fitness level. The volume of chest exercises in the P90X workout is adequate for building muscle mass, however the reps may be too high in some cases. Each of the six exercises is completed for two sets, meaning the workout consists of a total of 12 sets of chest exercises.
The P90X chest and back workout consists of six chest exercises, including standard push-ups, military push-ups, wide fly push-ups, decline push-ups, diamond push-ups and dive-bomber push-ups.
The weight you choose should be heavy enough that you reach muscle failure - you can't do another rep with good form - between reps eight and 12 on each set. To build mass - also called hypertrophy - the genral rule of thumb is to do sets of eight to 12 repetitions. A minimum of eight sets of exercises that directly target the chest muscles is a good goal, but doing more than that - 15 to 20 sets - is often recommended. In order to build the size of your chest muscles, you need volume and the right weight.