The p90x program is a training and nutrition program designed to deliver results in 90 days. Popularity of the program became exploded after a very aggressive infomercial campaign. These infomercials showcased people who acquired significant improvements in body composition and exercise performance after 90 days of the program.
While does deliver results, certain things should be considered before committing to the program. Among the things to consider include tolerance for physical discomfort, performance goals, long term adherence, and coordination/body-awareness. Determining your compatibility with p90x based on the aforementioned factors will help you determine if the program is right for you.
Tolerance for physical discomfort
What I mean by physical discomfort is the lung burn, muscle burn, and heavy breathing associated with intense exercise extended for a relatively long period of time. This program has numerous workouts that demand high levels of such discomfort. If being pushed to the brink of vomiting envigorates and rewards you, this program will keep you motivated. If, however, your life is such that sleep and recovery are spread thin, this program might kill your resolve.
Performance goals
P90x will not enhance all performance goals for everyone. For people who, overall, are deconditioned, this will improve all components of fitness if they fully recover from all the workouts. If you are highly conditioned in a certain fitness component like strength, power, and endurance, devotion to such programs might result in regression of that high level of conditioning; as this program spreads effort over several components of fitness.
Long-term adherence
The influence this program might have on one's long-term adherence to exercise and wellness should also be considered. This is a 6 day /week program with pretty strict nutrition guidelines that will deliver results if implemented. Such a committed regimen, however, can either instill an "all or nothing" attitude about lifestyle, or lay a foundation of fitness that inspires strive to maintain. Knowing how your attitude might be influenced by this program should sharpen your decision.
Coordination/body-awareness
How well/efficiently you navigate your body is important to consider when contemplating the program. If you're certain that you assume durable biomechanics when performing most exercises, you should be safe partaking in this program. If, however, you tend toward positions like a rounded-back and/or awkward knee-alignment when lifting, you might be vulnerable partaking in this program.
Conclusion
P90x is an effective program when implemented as intended. Things to consider, however, before embarking on the program include fatigue tolerance, performance goals, effect on long-term adherence, and coordination. If fatigue rewards rather than punishes this program works. On the performance goals front, consider whether this program entails enough exposure to your desired performance area. As to long-term adherence, intense exercise can inspire a life-long love or disdain for exercise. Regarding coordination, p90x entails some exercises that, in my opinion mandate body awareness many don't have. So consider as much as possible before committing to any training/nutrition program.