Hi again Will,
I'm sorry if I caused you any additional anxiety with my suggestion about your neighbors, honestly that was probably just my paranoia coming through. Once again I am sorry to hear you are dealing with this. I tend to agree with Sarah, and Una is right that people don't normally walk on the balls of their feet. I would recommend not working out in the middle of the night just to avoid waking anybody but otherwise I think it's possible your neighbors may be a little oversensitive. I hope you are able to relax.