Mine is just base on Jack Daniel's Vdot metrics. VO2max at 50 is the borderline for sub 20 mins. Some at this level can, and some can't. If your VO2max is around that number say 48 to 52, it's worthwhile to chase this sub 20 as goal. Just trying to correct a concept that seems on youtube that suggest that when you follow this and that training, anyone can go from 30min 5km to sub 20 sub in 10 weeks. For some people like me at VO2max 42, it's almost zero chance. I know it when my Vo2max improvement has plateau.
Vdot = Vo2max X RE , so a Vdot of 50 is that borderline for sub 20. Vo2max of 50 X re of 1 is that border.
Vdot is a good indicator of current performance. It does give an indicator over a period of time especially if you don't really improve much and stagnate.
The way I see it is more of predicting future performance especially for runners that are new/haven't run consistently with high mileage but are looking to do so in future. For example, my Vdot now is 55 (low 19 min based on Garmin), but I run 4 x 800m (2.4km pace) w/ equal rest at 2.48 average. That translates into a sub-18 minute 5k pace.
Sub-18 minute is achievable for me only if I continue to focus on 3/5k specific workouts. And this must be done over couple of years. Also, includes training plan adjustments like increasing mileage and cutting down pace during interval sessions.
Those youtube videos are not very accurate because it says anyone can do that. But I disagree with those and prefer future projection workouts (3k workouts give an idea of 5k potential for what is to come).
