Ok so I ran a 19:17 5k and I think that brings my 2-3mmol lactate pace to around 6:40 per mile. I am new to threshold running and don’t really understand how progression works. I am planning to run 3x miles and 5x1k workouts to start, on a treadmill for best pacing, but I am confused how progress works. Do i lower the pace by like a second each time I do the workout? For instance this week I do 5x1k at 6:40 then next week 3x Mile at 6:39? When do I know my lactate threshold has improved? I am in highschool looking to drop my 800-5k times.