I have had my treadmill for a couple years. I had been training on it for a marathon, and recently the belt skids as I am running on it. It starts going and stops abruptly, then continues to go. I have almost fallen off of it. My boyfriend has loosened it as well as tried tightening it. He has applied lubricant as well. What can be wrong with my treadmill? How can I fix it?

Thank you!

You have a slip point from ware,every Treadmill has a tension ajustment,if your’s is at its limit,you can spray it with none slip belt dresing,,if this does not work,your belt has to be change..I’m sorry I change many belts in my life..