The P90X home fitness system developed by Tony Horton is based on a 90-day schedule during which you follow seven workouts over 13 weeks to go from flab to fab. However, you can't just dip into the P90X program and use the bits you like and discard the rest. To achieve the results that the system offers, you must follow the week-by-week workout to the letter.
Follow the Phases
The classic P90X workout has three phases. The first covers weeks one through four. For the first three weeks you learn and repeat a seven-day series of exercises. In week four you learn core synergistics to practice alongside yoga, kenpo and stretching exercises. Phase two uses the same structure, with weeks five through seven repeating the same routine. Week eight repeats week four's schedule. The third phase is slightly different. Weeks nine and 11 use one set of exercises, and weeks 10 and 12 use a different set. Week 13, which ends the program, focuses on yoga, core synergistics, kenpo and stretching. On the seventh day of every week you may either rest or do stretching exercises.
According to Horton, the effectiveness of the P90X relies on "muscle confusion," which is why you must follow his sequence as set out in the instructions. This approach uses targeted training phases that prevent your muscles from becoming familiar with a your routine. This confusion keeps your muscles progressing throughout the 90 days, whereas a regular, unvaried routine may cause the process of change to slow down.