I used to workout on a treadmill back in the day. Lots of people still do. Unfortunately I had a horrible treadmill accident and have been unable to get back on that thing. You have to be extremely careful while on them. You have to pay close attention to what you're doing and not take the focus off your feet on that belt. If you step too far to one side or the back you could really injure yourself. These people have thrown caution to the wind for the most part and decided to either hurt themselves on purpose or are actually trying to workout. You be the judge. Watch!