The Stepto 8x4: eight 4-minute efforts at 103–110% of FTP, with 2 minutes' recovery between them. 32 minutes of work in a 71-minute session. For trained riders preparing for a time trial or an effort of around an hour.
| Target | Zone | Time | FTP 200 W | FTP 250 W | FTP 300 W |
|---|---|---|---|---|---|
| 103–110% | 5VO2 Max | 32 min | 206–220 W | 258–275 W | 309–330 W |
| 50–60% | 1Recovery | 14 min | 100–120 W | 125–150 W | 150–180 W |
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A 40 km time trial is ridden around your threshold, for an hour or a bit less. The 8 × 4 has you working just above that intensity, at high volume: 32 minutes of effort, cut into pieces short enough to hold more power than you'd race at. You get your body used to producing, and coping with, a little more than race day will ask.
In 1999, Nigel Stepto compared five interval formats in trained cyclists, from 30-second sprints to 8-minute blocks. The 8 × 4 was one of the two that improved 40 km times the most. The study is small and short, but it measures performance directly, which few sessions can claim.
Trained riders preparing for a time trial, a triathlon or a long breakaway, who know their FTP. If you've never done VO₂max intervals, start with fewer efforts: six instead of eight, or the 4 × 5 min.
In the study, riders did 6 sessions in 3 weeks: a short block, ideally placed a few weeks before a timed event. Otherwise, one session like this a week is plenty, with an easy day before and after. To ease in, start with six efforts, then go to eight once the power stays even to the end.
5′ at 45–55% FTP + 5′ at 56–65% FTP + 5′ at 66–75% FTP
15 minutes building from 45 to 75% of FTP, in 5-minute steps. If you're preparing for a time trial, ride the session in your race position: it's the moment to check you can hold it at this intensity.
8 × 4′ at 103–110% FTP, 2′ recovery
Eight 4-minute efforts at 103–110% of FTP, or 258 to 275 W for an FTP of 250 W, with 2 easy minutes at 50–60% between them. Hold the same power from the first to the eighth: better to finish slightly under target than crack on the fifth. Counting down from the fifth effort helps.
10′ at 40–55% FTP
10 very easy minutes at 40–55% of FTP. If the last two efforts fell well below the range, stay at the bottom of it next time, or go back to six efforts.
Hard but steady, without the punchiness of shorter efforts. The first four go well, the fifth marks halfway, the last two take concentration. It's a session of patience: the same thing eight times over, without letting up. Guide: 8 out of 10.
Same 32-minute total just above threshold, same 2-minute recovery. But Stepto splits it into eight 4-minute efforts, Seiler into four 8-minute ones. The shorter efforts of the 8 × 4 are often ridden a little higher; the 4 × 8 asks you to last.
Four minutes sounds short, and the first efforts tempt you above 110%. The bill arrives around the fifth. Start at 103% and only go up if the fourth still feels easy.
If you're preparing for a time trial, doing the session sat up on the hoods prepares you poorly. The aero position costs a few watts: better to learn that here than on race day.
The tested protocol is two sessions a week for three weeks, no more. Doing it every other day only adds fatigue.
Stepto et al. (Med Sci Sports Exerc 1999): 20 trained cyclists split across 5 formats, from 12 × 30 s to 4 × 8 min, 6 sessions in 3 weeks. The biggest 40 km time-trial gains, about +2.8%, came with this format and with 12 × 30 s at 175% of maximal aerobic power. The study prescribes 85% of maximal aerobic power measured in an incremental test; taking that as roughly 120 to 130% of FTP gives 103–110% of FTP, a Wattson approximation. The recovery length isn't given in the abstract consulted: the 2 minutes, the warm-up and the cool-down are Wattson choices. An earlier study from the same group (Lindsay et al., 1996) used 6 to 8 × 5 min at 80% of maximal aerobic power. Small sample, short intervention. Bottom line: good evidence for the protocol.
At 103–110% of FTP: 206 to 220 W for an FTP of 200 W, 258 to 275 W for 250 W, 309 to 330 W for 300 W. The study set the target as a percentage of maximal aerobic power; converting it to % of FTP is an approximation. Stay at the bottom of the range until you can hold all eight.
The same total, cut differently: eight 4-minute efforts for Stepto, four 8-minute efforts for Seiler, with 2 minutes' recovery in both. The 8 × 4 comes from a study on 40 km time trials; the 4 × 8, from a study on VO₂max and threshold. Both are equally good staple sessions.
In Stepto's study, yes: along with one other format, it produced the biggest 40 km gains after only three weeks. But the sample was small and the intervention short. It's a good reason to try it before a timed event, not a promise of results.
Yes, and it's a good idea if you're preparing for a time trial: the aero position limits your power a little, and getting used to it at this intensity is part of the job. On a turbo, raise the front wheel if needed to match your position, and keep a fan in front of you.
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