VDOT calculator for longer Tempo runs and HIIT/Tabata

I’ve updated my VDOT calculator with a couple of new features:

• It will show the modified tempo runs based on the Jack Daniels recommendations. These are the longer, slower tempo runs up to an hour in duration. I’ve used the values from the book, but they are only for VDOT increments of 5, so I’ve added some linear interpolation to give the other values. I’ve also done some calculations for slower runners with VDOT below 30.
• I’ve added the paces for High Intensity Interval Training and Tabata.
• The value for the 800 meter 'I' interval is not interpolated from other values.
• There is a bug fix for the VDOT calculations for runners slower than a 4:50 marathon, which Jack Daniels does not have in the book