Interactions with treadmills are based on pressing buttons or through a touchscreen. However, these interactions require the user to touch the frontal dashboard of the treadmill while running. Indeed, for each interaction that the runner does, the user needs to break her/his running form to reach the interface. Those actions cost also some additional energy to the runner with a possible impact on performance. Current technologies allow finding a better solution for the runner like gesture-based interaction. This paper presents a comparison of different interaction modalities, including gestures, on a treadmill. The goal of this study is to analyze the ergonomics of gestural interfaces while running on a treadmill. In fact, specific tailored gestures are perceived as more natural and easier to perform while doing an activity and can improve significantly the user experience.