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Sweet Spot (88% FTP) · 70 min
Two 20-minute blocks at 88% FTP. The workhorse threshold-builder for indoor cycling blocks.
Positioning
Sweet Spot sits in the 84–93% FTP band — hard enough to drive threshold adaptation, easy enough to sustain for 40+ minutes of work. The 2×20 structure is the default threshold builder for Veloarchitect Athletes in the build phase; it appears repeatedly across weekly Adaptive Workout dispatches.
Sweet Spot work is the engine-room of indoor threshold building. The Athlete’s Mechanical Efficiency moves consistently across 8-week Sweet Spot blocks; FTP test deltas of +12–18W are typical when the Athlete is otherwise recovered. The 2×20 structure is intentionally compact — long enough to drive cardiac adaptation, short enough to be repeatable inside a 75-minute indoor session.
Protocols: Protocol 3 — Threshold Sustain
Structure
15min WU · 2×20min @ 88% FTP / 5min rest · 10min CD
15-minute warm-up ramp 50→75% FTP
20-minute Sweet Spot block @ 88% FTP
5-minute recovery @ 55% FTP
20-minute Sweet Spot block @ 88% FTP
10-minute cool-down @ 50% FTP
Worked Example
Athlete: 36y/o, 268W FTP. 6-week block: 2 weekly Sweet Spot 2×20 sessions + 2 Z2 endurance + 1 Recovery Spin. Mechanical Efficiency moves 1.49 → 1.57 W/bpm. FTP test on week 7: +14W. ZWO→FIT Delta on the second 20-minute block averaged -3W; Execution Precision on the block: 0.96. Protocol 10 dispatches the next block at +5W on each Sweet Spot interval target.
Common assumption inverted
Sweet Spot is not “easy threshold.” The 88% target is hard enough that Drift across the 20-minute block is the primary limiter, not cardiac ceiling. The Athlete who treats 88% as “comfortable” will underdeliver and log a 0.91 Execution Precision — the system reads the underdelivery and rewrites the next block downward. Sweet Spot is supposed to be uncomfortable at minute 16; the Athlete who rides it comfortably is not actually doing Sweet Spot.
All Templates
See all eleven downloadable templates or the proprietary metrics glossary for the signals the Adaptive Workout reads.
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