Chris Farhood
85b6be4e36
Review of the VO2 conflict section against primary sources (verified via PubMed + search): - Rønnestad & Hansen 2016 (PMID 23942167) confirmed: 13 cyclists, 30s vs 50%/80% Tmax at 2:1 work:rest, measured time >=90% VO2peak, 30s won. Table row corrected to reflect the actual comparison. - Yang 2025 optimum ~140s is a MEDIUM rep (~2.3 min), between the poles. Section reframed from binary short-vs-long to an inverted-U with a modality/protocol-dependent peak. 'Weighted toward running' softened to match what the abstract actually supports. - Removed the overstatement 'best-controlled evidence favors short 30/15 intervals'. Added two caveats: (1) cycling short-interval superiority is largely one research group; (2) effort-matched work (total-work-matched) reportedly nulls the advantage (Seiler group; unpublished/secondary, flagged low-tier, not cited as fact). - Practical menu now defaults to medium (~2-4 min, near the pooled optimum) rather than short; short/long presented as goal-dependent options. - citations.md: added single-group caveat on Ronnestad body of work and an explicit NOT-VERIFIABLE entry for the effort-matched replication. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01TqrhBhC3GEcKyaw8RTk8G6
92 lines
6.1 KiB
Markdown
92 lines
6.1 KiB
Markdown
# VO2max interval optimization
|
||
|
||
**Load this doc when:** designing high-intensity interval sessions, choosing rep length or
|
||
work:rest, or trying to rebuild sustained aerobic power.
|
||
|
||
**Data/knowledge split:** MCP gives you the power/HR streams and interval stats to *check* whether a
|
||
session did what you intended (was power sustained across reps?). This doc gives the *design logic*.
|
||
|
||
---
|
||
|
||
## The target: maximize time spent ≥90% VO2max
|
||
|
||
The organizing principle of VO2max interval design is **accumulating time at or above 90% of
|
||
VO2max** — that's the stimulus, not simply "going hard." Design sessions to spend the most quality
|
||
minutes in that band that the athlete can repeat and recover from.
|
||
|
||
## What a large meta-analysis found (dose-response)
|
||
|
||
A systematic review with pairwise and network meta-analysis (**51 studies, 1,261 athletes**) found
|
||
inverted-U dose-response relationships and identified an optimum around **~140 s work duration** and
|
||
a **work-to-recovery ratio of ~0.85**, with ~3×/week over 3–6 weeks as an effective pattern (Yang,
|
||
Wang & Guan 2025, *BMC Sports Sci Med Rehabil* 17(1):156; PMID 40605061;
|
||
DOI 10.1186/s13102-025-01191-6).
|
||
|
||
> **Caveat — modality.** Yang 2025 describes its *optimal protocol* as running-based; the abstract
|
||
> does not give a cycling-vs-running breakdown across the 51 studies. Treat ~140 s / 0.85 as a
|
||
> cross-modal anchor, not a cycling-specific verdict — and note that **~140 s is a *medium* rep
|
||
> (~2.3 min): longer than 30s, shorter than the classic 5-min "long" interval.** The pooled optimum
|
||
> sits *between* the two poles people usually argue about.
|
||
|
||
## ⚠️ Rep length is unsettled and protocol-sensitive — not a solved short-vs-long question
|
||
|
||
A common coaching claim is that **longer reps (3–5 min) accumulate more time ≥90% VO2max than short
|
||
(30s) intervals.** The evidence does not settle this cleanly: it flips by modality, depends heavily
|
||
on how the protocols are built, and can wash out when total work is matched. Do **not** present
|
||
either "go long" or "go short" as established.
|
||
|
||
**The direct time-at-VO2max studies disagree by modality:**
|
||
|
||
| Modality | Finding | Source |
|
||
|---|---|---|
|
||
| **Running (acute)** | 3-min intervals accumulated **more** time >90% VO2max (~328 s) than intensified 30-s intervals (~201 s), even with 30-s intensity raised | Fleckenstein, Braunstein & Walter 2025, *Front Sports Act Living* 6:1507957; PMID 39835194; DOI 10.3389/fspor.2024.1507957 |
|
||
| **Cycling (acute)** | **30-s** work intervals induced **more** time ≥90% VO2peak than longer intervals (50%/80% of Tmax) at matched 2:1 work:rest, in 13 well-trained cyclists — the opposite result | Rønnestad & Hansen 2016, *J Strength Cond Res* 30(4):999–1006; PMID 23942167; DOI 10.1519/JSC.0b013e3182a73e8a |
|
||
| **Cycling (adaptation)** | Over 3 weeks, "effort-matched" **short** intervals (30/15 s) beat long (5-min) intervals — e.g. +4.7% 20-min power — in elite cyclists | Rønnestad, Hansen, Nygaard & Lundby 2020, *Scand J Med Sci Sports* 30(5):849–857; PMID 31977120; DOI 10.1111/sms.13627 |
|
||
|
||
**The pooled meta-analysis puts the optimum in the *middle* (~140 s / ~2.3 min)** — see the caveat
|
||
above. So the honest shape is an **inverted-U whose peak location shifts with modality and protocol**,
|
||
not a binary short-vs-long contest.
|
||
|
||
**Two reasons not to over-trust the "cycling favors short" side:**
|
||
1. **It's largely one research group.** The cycling short-interval superiority comes chiefly from
|
||
Rønnestad and colleagues (2016 / 2020 / 2021; Almquist 2020, PMID 32267032; Rønnestad 2021,
|
||
PMID 33735833). Internally consistent, but independent replication is limited.
|
||
2. **Effort-matching is the crux.** When independent cycling work matched **total work duration**
|
||
across formats, the short-interval *adaptation* advantage reportedly disappeared (attributed to a
|
||
Seiler-group study; **unpublished / secondary-source — low evidence tier, do not cite as fact**).
|
||
Much of the apparent edge may be that 30/15 sessions simply pack more total high-intensity work,
|
||
not rep length per se.
|
||
|
||
**Bottom line:** acute time ≥90% VO2max favors short intervals *in the Rønnestad cycling protocols*
|
||
and long intervals in the one running study; the pooled optimum is *medium* (~140 s); and
|
||
effort-matched adaptation data are equivocal. Treat rep length as a lever to **individualize**, not
|
||
a solved problem.
|
||
|
||
> ⚠️ **Under-researched — track individual response.** Optimal rep length for a *given cyclist* is
|
||
> not resolved. Use the MCP interval/stream data to verify what actually keeps power in the
|
||
> ≥90%-effort band across reps for this athlete, and let that — not a rule — drive the choice.
|
||
|
||
## Practical prescription
|
||
|
||
- **Menu for cyclists** (no format is proven superior — pick by athlete and goal, then verify per
|
||
rider with the MCP data):
|
||
- **Medium intervals (~2–4 min, work:rest ~0.85):** closest to the pooled meta-analytic optimum
|
||
(~140 s; Yang 2025) and a sensible **default** for most riders — long enough to bank time
|
||
≥90% VO2max, short enough to hold power across reps.
|
||
- **Short intervals:** 30/15 s (≈13 reps × 2–3 series) — banks time ≥90% VO2max well in the
|
||
Rønnestad protocols (2016/2020/2021); good for riders who fade on long reps or want more total
|
||
high-intensity work per session. Not proven superior once total work is matched.
|
||
- **Long intervals (~4–5 min):** favored by the running time-at-VO2max data (Fleckenstein 2025)
|
||
and useful for **sustained** aerobic power and race-specific steady demands; a reasoned choice,
|
||
not a cycling-proven one.
|
||
- **Prescribe from power.** For MTB especially, HR lags and misleads (`mtb-xco-demands.md`,
|
||
`data-confounds.md`).
|
||
- **Verify the session worked:** pull the interval stats/streams from MCP and check power held near
|
||
target across reps. Fading power = too much intensity or too little recovery; adjust work:rest.
|
||
|
||
## Frequency vs distribution
|
||
|
||
For *how often* to do hard sessions and how they fit the week/season, see `periodization.md` — the
|
||
argument there (after Seiler 2024) is that the **long-term integration** of frequency, intensity,
|
||
and duration matters more than chasing the acute maximum of any single session.
|