Elite coaching, powered by your biometrics.
Synchronizing biometric stream...
Calibrating structural models...
Stabilizing neural uplink...
Awaiting data packet finalization
The Architect is an independent analysis tool and is not affiliated with, sponsored by, or endorsed by Zwift, Inc. or Rouvy or Whoop. Zwift, Whoop and Rouvy are trademarks of their respective owners. Support for .zwo and .fit files is provided for data interoperability and personal performance analysis only.
© 2026 VeloArchitect. All rights reserved.
Powered by Biometrics from WHOOP
VO₂max (110% FTP) · 60 min
Four 4-minute intervals at 110% FTP, 4-minute rest. The Norwegian protocol — short, hard, and bracketed by Z2.
Positioning
The Norwegian 4×4 is the most-cited VO₂max protocol in the indoor literature. Four minutes is long enough to drive VO₂ toward ceiling, short enough that the Athlete can complete four clean reps. Veloarchitect Athletes in the peak phase receive this template as the default supra-threshold work; Adaptive Workout may rewrite the intensity or reps based on the Athlete’s Failure Horizon projection.
The 4×4 structure is the supra-threshold lever. The Athlete’s Adaptation Rate for VO₂max-specific work moves fastest across 4–6 week blocks of twice-weekly 4×4. The protocol is hard — minute 3 of interval 4 should be the hardest work the Athlete has done that week. The Failure Horizon projection tightens during the block; the Athlete who skips the cool-down or underdelivers on interval 4 collapses the horizon.
Protocols: Protocol 2 — VO₂max Repeats
Structure
15min WU · 4×4min @ 110% FTP / 4min rest · 10min CD
15-minute warm-up ramp 50→80% FTP
4-minute VO₂max block @ 110% FTP
4-minute recovery @ 50% FTP
4-minute VO₂max block @ 110% FTP
4-minute recovery @ 50% FTP
4-minute VO₂max block @ 110% FTP
4-minute recovery @ 50% FTP
4-minute VO₂max block @ 110% FTP
10-minute cool-down @ 50% FTP
Worked Example
Athlete: 38y/o, 282W FTP, 1.61 W/bpm. 4-week block: 2 weekly 4×4 sessions + 1 weekly Threshold Sustain + 2 Z2 endurance. Interval 1 average power 308W (109% FTP). Interval 4 average power 287W (102% FTP, drift). ZWO→FIT Delta on interval 4: -25W. Execution Precision: 0.84. Failure Horizon projection post-block: 96 hours. Week 5: Adaptive Workout rewrites interval 4 target to 105% FTP pending recheck.
Common assumption inverted
The 4×4 is not a “just do it hard” session. The 4-minute rest is structurally part of the work; the Athlete who shortens the rest to 2 minutes produces different physiology (more anaerobic, less VO₂max-specific) and logs a lower Mechanical Efficiency shift. The 4-minute rest is also the window in which the Failure Horizon projection is recomputed; the Athlete who skips rest is bypassing the read.
All Templates
See all eleven downloadable templates or the proprietary metrics glossary for the signals the Adaptive Workout reads.
Related