: An explosive cardio session designed to improve athletic performance [5].
Created by Tony Horton and Beachbody, P90X (Power 90 Extreme) is a home fitness regimen that exploded in popularity in the mid-2000s. It is famous for "Muscle Confusion" and the brutal 12-disc workout set including Chest & Back , Plyometrics X , Shoulders & Arms , and the dreaded Ab Ripper X .