It is pretty simply to do in MS Excel I will try and paste it below. If it doesn't work send me an email at
adam_seanor@scotiacapital.com and I will send it to you
Distance: 500 Time: 0:06:40 100 Pace 0:01:20 50 Pace 0:00:40 25 Pace 0:00:20
The formula is (time)/(distance/pace distance - 100,50, 25). You have to set the cell format such that it recognizes the times as hh:mm:ss. You do this by selecting format. First select time and then go to custom and the options you want will apear. If you have any questions drop me a note. Obviously this works for any sport just vary your divisor accordingly.
Adam