This model is the most commonly found Life Fitness® treadmill in commercial environments in the US and features FlexDeck technology, which cushions the impact reducing the stress on the knees and joints. 9100HR Treadmills have Lifepulse hand sensors to monitor your heart rate during workouts as well as Polar® hands-free heart rate monitoring capability. This commercial unit also incorporates an automatic self-waxing system, which regularly lubricates the deck and helps to increase belt life by decreasing friction between the belt and deck.