2 weeks ago I did my first track workout, yesterday I did my second. And in those 2 weeks, I got faster!
On 7/29 I ran 6 x 400’s and averaged 1:30 per lap. Yesterday, I ran 7 x 400s and averaged 1:26 per lap.
Bonus is that, yesterday, I ran with a heart rate monitor, so I can use that HR data the next time I do this workout to see how my body responds to this kind of pressure.