Good Evening All,
HI thought I’d share some details as to why Matt and David choose to divide the zones the way they did.
First, let’s start by defining some terms
VT1 = Ventilatory Threshold 1: The first point at which an athlete’s breathing rate spikes.
VT2 = Ventilatory Threshold 2: The second point at which an athlete’s breathing rate spikes.
VO2max: The limit of the capacity to accept oxygen.
Lactate Threahold: The intensity at which lactate begins to accumulate in the blood.
Now, all 4 of these require laboratory testing to 100% accurately determine. Luckily, we can determine their functional equivalent (or a close enough value if you will) using field testing.
A 20 minute field test can determine a Fuctional Lactate Threahold. A 6 min field test can be used to determine a functional VO2max.
VT1 is the breaking point between low and moderate intensity workouts. Anything below VT1 is considered low intensity. Zone 1 and Zone 2 is all low intensity. As athletes we have discretion to determine where within that range we need to be on any given day. Some days we are tired and some days we are hot or dehydrated. Time below the VT1 counts as the 80% easy whether it is Zone 1 or Zone 2. The break between Zone 1 and Zone 2 isn’t to be considered a hard break. It’s more a general break to help distinguish between recovery and easy runs. That said, if you are rested and feeling well, there is no danger in doing a Zone 1 workout in Zone 2.
VT2 is the breaking point between moderate and high intensity workouts. Now, the 20% of 80/20 Emdurance includes both high and Moderate intensity. The amount and volume of high versus moderate is actually based more in the races you are training for and your goals. VT2 is the breakpoint of Zone 4. Above VT2 and you are in Zone 4. The upper end of Zone 4 is the maximum pace you can sustain for 6 minutes. It’s closer to what elites would run a 1 mile race.
VO2max is the breaking point between Zone 4 and Zone 5. Since VO2max is limit to accept oxygen, you can’t sustain this level for long before you physically can’t run any longer. You can’t run a 5K in Zone 5. It’s not physically possible.
Now that we have some reference for the upper ranges, I’ll expand on what Zone X and Y are. Zone Y is that small gap between Lactate Threshold and VT2. The upper limit of Zone Y is sustainable for 20-30 minutes. This is why most runners will be running a 5K somewhere between Zone Y and lower Zone 4.
The upper level of Zone 3 is considered sustainable for 60 minutes maximum.
Then we have Zone X. It’s sustainable at the upper level for 2 hours. It was originally put in place by Matt as an unamed gap between. VT1 and the beginning of Zone 3. It, and Y, weren’t named. This caused confusion and Matt subsequently went back and named them X and Y to eliminate the confusion.
I’ll end with some general guidelines on Zone 2. Upper limit of Zone 2 is the highest intensity at which it is possible to speak comfortably. So if you can’t talk to your running partner, you are no longer in Zone 2.
80/20 Certified Coach