In REN, your training isn’t based on a single number. Instead, we work with three independent thresholds:
VO₂max Pace → your aerobic ceiling (6 minutes all-out)
Critical Speed (CS) → your maximum steady-state pace (30 minutes all-out)
Aerobic Threshold (AeT) → your aerobic efficiency (tested over 50–90 minutes)
Why Different Tests?
These thresholds are not fixed percentages of each other.
Some training systems assume, for example, that your Aerobic Threshold (AeT) is always a set percentage of your Critical Speed (CS).
But in reality, physiology varies:
Highly endurance-trained runners can sustain a pace very close to their CS without drifting in heart rate, meaning their AeT is relatively high.
Less endurance-trained runners often show an earlier rise in effort and heart rate, so their AeT sits much lower compared to CS.
Similarly, VO₂max pace isn’t just a “fixed step above CS” — some athletes can go much faster, others only slightly.
Because of these differences, REN measures each threshold separately with its own test, instead of relying on rough percentages. This way your training plan reflects your personal physiology, not an average assumption.
Critical Speed Test
Purpose: Determines your maximum sustainable pace in a physiological steady state.
Prerequisite: You should be able to comfortably run at least 45 minutes.
How to Perform:
Warm up properly, with ≥10 minutes easy running.
Run 30 minutes at your best steady effort.
Choose a flat, familiar course with minimal wind.
Focus on even pacing and covering maximum distance.
Use a GPS watch and heart rate monitor (chest strap recommended).
VO₂max Pace Test
Purpose: Assesses your aerobic ceiling and sets the intensity for high-intensity intervals (HIT).
How to Perform:
Warm up with 10 minutes of easy running.
Add dynamic drills or short accelerations.
On a flat course, run 6 minutes all-out, aiming for even pacing.
Record pace and heart rate with a GPS watch and chest strap.
Aerobic Threshold (AeT) Tests
Purpose: Evaluates your aerobic efficiency.
Test Options: 50, 70, or 90 minutes — the longer, the more accurate.
How to Perform (50-minute version):
Warm up with 10 minutes easy running.
Run 40/60/80 minutes at AeT pace (≈30–40 sec/km slower than CS).
Keep effort steady, avoiding surges or fatigue.
Use GPS and a chest strap HR monitor.
REN compares HR and pace in the first vs. second half of the 40 minutes.
Result:
If aerobic decoupling (difference in HR/pace ratio between halves) is <5%, your AeT is confirmed.
If higher, REN adjusts your AeT pace to be a bit slower for training.
When and How REN Plans Tests
Readiness-based: REN only schedules tests when you are prepared for their duration and intensity.
Repetition: Tests are repeated every ~8 weeks to keep your thresholds accurate.
Skipped Test? If you miss one, REN will try to replan it the following week.
Test Sequencing: An AeT test is typically scheduled the week after a CS test for optimal progression.
Comparison of Exercise Tests in REN
| Test | Purpose | Duration | How to Perform |
|---|---|---|---|
| Critical Speed (CS) | Max steady-state pace | 30 min all-out (after 10 min warm-up) | Even-paced hard effort on flat course, GPS + HR monitor |
| VO₂max Pace | Aerobic ceiling, guides HIT intervals | 6 min all-out (after 10 min warm-up + drills) | Run as hard as possible for 6 min, even pacing, GPS + HR monitor |
| Aerobic Threshold (AeT) | Aerobic efficiency, long-term endurance | 50–90 min (after 10 min warm-up; main block 40–80 min) | Run ~30–40 sec/km slower than CS, steady effort; GPS + chest strap HR monitor |
✅ In summary: REN uses independent exercise tests for VO₂max pace, Critical Speed, and Aerobic Threshold. Together, they provide the most accurate picture of your fitness and ensure your training plan is personalized to your physiology.