Unsafe product. Yes, its manual, but it's not smooth. You're too busy hanging on for dear life rather than enjoying your treadmill experience. The frame is too small and rickety for such use (the hanging on for dear life part).If it was smoother, the work out WOULD be worth it since its naturally on an incline and it makes you work it. But, its not worth risking your safety over. Just buy a power driven model so you don't have to wonder if you're going to trip and break a leg.Its so dangerous that I refused to give it away. I just disassembled it and tossed it out on separate trash days to avoid someone from adopting it for themselves.