Training Zones · Performance Science · 2026
Not all intensity is equal.
5 ZONE
SYSTEM
@drdragutin
01 / 08
The Full Spectrum
5 Zones.
One System.
@drdragutin02 / 08
1
Training Zone · 01
ZONE 1
ACTIVE RECOVERY
Below VT1
Fat Dominant
Full Conversation
Very easy effort. Minimal metabolic strain. Almost entirely fat-fueled. Purpose is recovery, not adaptation.
Intensity
Very easy — could sustain for hours
Lactate
At resting baseline — no accumulation
Fuel
Fat dominant — minimal glycogen
Purpose
Active recovery · Warm-up · Cool-down
@drdragutin03 / 08
2
Training Zone · 02
ZONE 2
AEROBIC BASE
Just above VT1
Mitochondrial Zone
LT1 Development
Most important zone for long-term performance. Conversation still possible. Builds mitochondrial density and shifts LT1 to the right.
Intensity
Easy-moderate — 60–180 min sustainable
Lactate
Just above VT1 — stable and controlled
Key rule
Most athletes train this too hard — stay disciplined
Adaptation
Mitochondria · Fat oxidation · LT1 shift right
@drdragutin04 / 08
3
Training Zone · 03
ZONE 3
THRESHOLD
Near LT2
Limited Sentences
LT2 Development
Demanding but sustainable. Last zone before lactate accumulates continuously. Key for raising the LT2 ceiling.
Intensity
Moderate-hard — 20–60 min sustainable
Lactate
Approaching LT2 — rising but manageable
Breathing
Labored — short sentences only
Protocol
2×20 min at LT2 pace · Tempo intervals
@drdragutin05 / 08
4
Training Zone · 04
ZONE 4
HIGH INTENSITY
Above LT2
Lactate Accumulates
Clock Counting Down
Point of no return. Lactate accumulates continuously. H+ rises. Time to exhaustion becomes limited.
Intensity
Hard — 2–15 min per interval
Lactate
Above LT2 — continuous accumulation
Recovery
Wait until HR = VT1 before next rep
Protocol
4×400m · 8×800m — VT1/VT2 Biofeedback Rule
@drdragutin06 / 08
5
Training Zone · 05
ZONE 5
NEUROMUSCULAR
Maximal
Phosphagen Dominant
0–10 Seconds
Maximum output. ATP-PCr system dominant. Duration 6–10 seconds peak. Speed, power, explosiveness. Extreme CNS demand.
Intensity
100% maximal — 6–10 sec peak
Fuel
ATP-PCr — phosphagen stores only
Recovery
3–5 min full rest — PCr restoration is aerobic
Warning
CNS fatigue accumulates fast — quality over quantity
@drdragutin07 / 08
Next Step
TRAIN THE
RIGHT ZONE.
EVERY TIME.
Generic heart rate formulas are guesswork. Personalized zones from VT1/VT2 data are the only way to guarantee adaptation.
drdragutin.com/resources.html
Free 5 Zone Guide · Link in Bio
@drdragutin08 / 08