1. Perhaps it is because I am using a small laptop but when I load your site the only thing I see is your HUGE banner. If I scroll down I Still only see your banner. If I scroll down more Then I can see the actual content of your site. If I didn't scroll down I would just assume your site didn't load, then close it and move on.
2. The intervals need to be entered in Metric and the mileage needs to be entered in Imperial. Is that intentional? Even in the states I wouldn't think that would be ideal but for everyone else in the world forcing us to convert our mileage into imperial before entering it will stop most from even bothering (It did me, so I can't comment on anything else). I would think adding a km/Mi and m/yd selection would be an easy addition and would make it way more functional.
3. Here is a copy and paste from your site:
"workout date
(mm/dd/yyyy)
yyyy-mm-dd" (this is on the actual data entry field)
So which is it, year first or year last?