S-Force leverages intelligent biomechanics to deliver the most rigorous version of HIIT in all of fitness, whether you’re using it as a challenging part of your circuit, for small group training or as a stand-alone station on your cardio floor. As members move through a user-defined path that fits their individual stride, the magnetic system automatically increases resistance the harder they work. This progressive design means that each interval will challenge HIIT enthusiasts and even elite athletes.