Recently bought it and was able to use it for around 9 miles, took me a little over an hour, it felt like an excellent workout, I was exhausted, I am in good physical condition, I am a runner, I was looking for something to alternate in between my running days; however, later that day my left knee was kind of hurting every time I retracted my legs, seems because it was my first day using it and learning to use it simultaneously, I did not realize how much sideways bending my knees were getting. The next day, however, the knee pain was almost 99% gone and I felt incredible, as if my tendons and joints had strengthened overnight (I used to do spinning at the gym and know the good effects of a good spinning session) so I went for a run, I ran 5 miles in 50 minutes, 30% faster than usual. It is an amazing workout machine, but one have to get to know it to prevent injures and get the most out of it, it is an acquired taste for sure! Go Halfbike! Hans Gordillo
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