Running intervals 14:00 
did my own version of a beep test.
had to get under the following lap times, and then after these 8 i just had to see how long i could go doing under 50s laps.
1st try: got ~51s on my last lap.
2nd try: completed 9 but was a bit over 50s on my last 2.
was pretty tired by the end, hopefully i can do this once in a while and improve.