I have the PRO-FORM 700 Cardio Cross Trainer. It has been working very well up until today. When I started to use it there was a large amount of resistance. The resistance was so strong that it barely moved. If I used all my force to move it for about a minute, it would eventually start to move again. As I continue to do my workout, it would eventually get tough again. If I started moving backwards it would also start to loosen, but just a little bit.