John: endurance power doubled across the season
John shows why structure matters for busy riders: the goal was not more random training, but making each session count toward road and gravel performance.
Doubled endurance power in 21 weeks

Result at a glance
- Main outcome
- Doubled endurance power
- Timeframe
- 21 weeks
- Rider context
- New father, full-time worker and road/gravel racer
- Product used
- Team SEMIPRO
Where this rider actually started.
Just over two years into the sport, self-coaching by assembling standard training plans himself, with no overall strategy connecting them.
Critical power 321 W. Four-hour endurance power 1.6 W/kg. Threshold time to exhaustion and late-ride power were both untrained rather than absent.
Goal. Raise threshold, increase endurance power, and perform in road and gravel races.
Main constraint. A new baby, full-time work, and a life outside cycling. Every session had to count toward something bigger.
The decisions behind the result.
- November to January: a buildup period extending endurance capacity ahead of a first race on 30 March and a first major race on 20 April.
- February: a four-week VO2max and neuromuscular power block.
- March: sub-threshold work aimed at time to exhaustion at threshold.
- April to June: race-specific development chosen against what the opening gravel races demanded — an anaerobic block for attacking and chasing, then a muscular endurance block for torque on climbs and long efforts.
- July to September: peaking and refining, with a lactate clearance block, a return to VO2max in August, and the season peak in September.
- Throughout: intervals paced on how the day actually felt rather than on the number written in the calendar — harder when the signal allowed, pulled back when it did not.
What was actually measured.
Grouped by what kind of evidence each number is. A race result, a recorded power file, a model estimate and a rider’s own impression do not carry the same weight.
Race or event result
- First race of the season
- Second out of 150 riders, after losing a water bottle early and battling cramps. Set peak 1-minute, 1-hour and 90-minute power in the same race.
Recorded or tested power
- Four-hour endurance power
- 1.6 W/kg to 3.2 W/kg, a 100% increase. This specific measure is what "doubled endurance power" refers to.
- Late-ride 5-minute power
- 4.5 W/kg to 5.9 W/kg after a substantial work load, a 31% increase.
- Peak 5-minute power
- A new personal best of 439 W in mid-August, about 8% up on earlier in the year.
- 10-minute torque
- Improved 14% after the muscular endurance block in May.
Modelled power
- Critical power
- 321 W to 356 W across the season, a 10.9% increase.
- Threshold sustainability
- Time to exhaustion at threshold improved by nearly 6%. Stamina beyond one hour moved from 73% to 80%.
- VO2max
- 4.9 to 5.02 L/min after the February block, reaching a season peak of 73 ml/kg/min in August. These are estimates derived from training data.
The useful takeaway.
- Supports SEMIPRO claims around endurance development and durability.
- Adds a medium-term proof point between short blocks and full-year coaching.
- Makes the phrase durable cyclist easier to connect to measurable change.
- Supports the claim that block sequencing should be chosen against what the target races demand, not run in a fixed textbook order.
What this example does not prove.
- "Doubled endurance power" refers to one specific measure — four-hour power in W/kg — not to a doubling of overall fitness. Critical power over the same period rose about 11%.
- A rider two years into structured training has far more headroom than a long-trained athlete.
- The season contained many blocks run back to back. No single block is isolated as the cause of any single number.
- Critical power, VO2max and stamina figures are model outputs derived from training files, not laboratory tests.
- Individual result, no control group.
Where this comes from.
Source video with full transcript
How This Training Plan Doubled Endurance Power in 21 Weeks
Full transcript
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