Determining the energy cost and exercise intensity of four of the P90X workouts

Abstract

Purpose: P90X is the #1 fitness program in America, but there is little research to back its credibility. This study was designed to determine the energy cost and exercise intensity of four of the 12 P90X workouts. Methods: Sixteen subjects (9 males and 7 females) completed treadmill VO2max tests to determine their aerobic capacity. Heart rate (HR) and oxygen consumption (VO2) were measured and individual HR/VO2 regression equations were determined. After practicing the workouts, each subject performed one workout per day with a minimum of 48 hours of rest between sessions until all 4 workouts were completed. HR's were measured during testing and input into the HR/VO2 regression equations to predict VO2 and caloric expenditure. Results: Average HR values from the four workouts were between 67- 83% of HRmax for males and between 65 - 88% of HRmax for females. Average %VO2max values were between 45 - 70% for males and between 45 - 80% for females. Average kcals/min expended were between 10.5 - 16.2 kcals/min for males and between 7.2 - 12.6 kcals/min for females. Discussion: The four P90X workouts meet ACSM recommendations for both energy cost and exercise intensity for both males and females. Therefore, the four P90X workouts tested are a viable option for those looking to lose weight or improve cardiorespiratory fitness.