Abstract: We present a study and game design that explores how motion controlled physical activity levels can be used to support exergaming and an improved user experience in a traditional game genre. We developed DynoFighter, a two player full body competitive fighting game where a player's activity levels influence their strength in the game, making it advantageous for players to exert themselves in order to win. We conducted a between subjects experiment to compare DynoFighter with and without its physical activity incentive mechanism and examined players' heart rate and activity levels, as well as their overall user experience with the game. Our results show that although there were no significant differences in physical exertion levels, players showed significantly more immersion and enjoyment as well as an increase in perceived exertion levels with DynoFighter's physical activity incentive mechanism.