[Jtsummers]

  The volunteers warmed up for two minutes on stationary bicycles,
  then pedaled as hard as possible for 20 seconds; rode at a very slow
  pace for two minutes, sprinted all-out again for 20 seconds;
  recovered with slow riding for another two minutes; pedaled all-out
  for a final 20 seconds; then cooled down for three minutes. The
  entire workout lasted 10 minutes, with only one minute of that time
  being strenuous.

So it's:

  120 seconds slow
   20 seconds fast
  120 seconds slow
   20 seconds fast
  120 seconds slow
   20 seconds fast
  180 seconds slow
  ================
  600 seconds (10 minutes)

What you're doing is fine, and I'll encourage you to continue it or a variation of it (EDIT: especially since you're having fun, that's a key to keeping up a routine). However, that's not what the article described. The article describes a variation of HIIT (high intensity interval training).