A missed session or a broken week
Drop the easy one, move a key one only into a clean slot, never stack to catch up, and restart from the calendar instead of repaying the debt; the base measures no cost for a few missed days, and a sudden jump in weekly running distance is the risk it does measure, in runners
The question it answers
One or more planned sessions were missed (work, travel, family, a bad night): what is dropped, what is moved and where, what must not end up back-to-back, when the week is written off, and what the next week looks like. Illness and breaks beyond two weeks are SYNTH-36 (C+).
Default (what to prescribe first)
Do not repay missed training. Not from a study; the base's own practice: missed minutes are gone; the rest of the week is re-planned from today forward and never exceeds the week as it was planned. SYNTH-26 (B) states the same as inference: never add hard sessions to compensate for missing hours.
Rank what is left: key sessions first, then the long session, then the lift, then easy volume. Not from a study; the base's own practice.
What supports the order: in general populations endurance was held for up to 15 weeks on as little as 2 sessions/week or 33-66% less volume, only when intensity was maintained, and the review itself says data are insufficient for athletes (REF-587, B+, narrative review); a review of detraining gives the same recipe — keep intensity, reduce frequency only moderately, cut volume markedly (REF-374, B+, narrative review).
A missed easy session is dropped. A missed key session is moved only into a clean slot: an easy or off day before it and ≥48 h to the next key session (the gaps are house practice, SYNTH-70, B-). No clean slot → drop it and do the next key session as planned.
Next week starts as written, not heavier (not from a study; the base's own practice). After 7+ missed days in a row, step back first (table below).
Decision (who → what)
What to do with the missed session — amateurs, Tier 1-3; every row is practice unless a refId carries the claim.
| Missed | Do | Source and how sure |
|---|---|---|
| Easy or recovery session | Drop it. Do not add its minutes to another day | Practice. Volume is the variable that can be cut most while fitness holds (REF-374, B+; REF-587, B+, general populations) |
| Key session (VO2max, threshold), clean slot exists this week | Move it there, unchanged | In 15 male cyclists, four HIT sessions timed by a submaximal test instead of a fixed schedule gave a 40-km TT gain of 48 ± 42 s vs 8 ± 45 s at the same total dose (REF-753, B-, groups differed at baseline). Inference: a hard session done on a better day is not a lost session; the study moved sessions by a test, not by a diary |
| Key session, no clean slot | Drop it. Never place it the day before or after another key session to "fit it in" | Practice (SYNTH-70, SYNTH-28, B: 48-72 h between hard days is a house convention). In training, one Giro podium rider never went hard more than 2 days running (REF-080, C+, n=1, Tier 5 — transfer) |
| Two key sessions left, room for one | Do one; make the other easy | Practice. One HIT session every 7-10 days on top of easy riding gave very likely larger 4 mmol/L and 40-min power than easy riding alone over an 8-week transition in 13 well-trained cyclists (REF-166, B). Inference: one quality session keeps a week alive |
| Long ride (cyclist) | Move to any free day, or ride it shortened; it may sit next to a key session if kept below VT1 | HRV was back in 5-10 min after 60-120 min below VT1 in 9 highly trained runners (REF-161, B — transfer to cycling and to amateurs; longer rides untested). 24-48 h to the next key session is SYNTH-70 practice |
| Long run (runner) | Move only with 48-72 h to the next key session; otherwise run it shorter or drop it | After 3 days × 2.5 h, 13 trained runners had 133% higher CK and 87% more soreness than 22 trained cyclists (REF-235, B+); the 48-72 h is SYNTH-70 practice. The length of the weekly longest run correlated with economy durability (r = −0.67, 26 well-trained men, cross-sectional, REF-160, B) — a reason to protect it, not proof |
| Heavy lower-body lift | Drop it if the only free slot is within 24 h before a quality session; do not let a moved lift land there | A hard strength session impairs the next endurance session for "several hours to days" (REF-328, B+, narrative review, no hours); the 24 h is SYNTH-31 (B) practice. Strength was held on 1 session/week in general populations (REF-587) |
| Session missed because of a short night | Endurance key session: move it a day; strength, speed or skill work: train in the morning rather than the evening (revised 2026-10-12) | Across 69 studies (n=959, 89% men) ≤6 h of sleep cut performance ~7.6%; the abstract says afternoon/evening tasks were impaired and morning tasks largely spared, but the full text's pooled table shows AM −5.42% vs PM −8.31%, and endurance tasks were impaired at either time (AM −6.50%, PM −3.56%; not formally compared — the authors read it as irrespective of time of day) (REF-204, A-, single nights only) (corrected 2026-10-12). After 30 h awake 10 team-sport men sprinted slower with lower glycogen and unchanged RPE (REF-384, B — transfer) |
How many missed days change the plan — complete rest; reduced training with intensity kept limits the losses (REF-374).
| Gap | Next step | Source and how sure |
|---|---|---|
| 1-3 days | Nothing changes. Resume the plan where the calendar is | Practice; no entry prices this window. In 300,000 recreational marathoners over 50% had complete stops of up to and including 6 days in a build per the abstract (its Results instead report a stop of at least 7 days in about 55-58%; corrected 2026-10-12), and those were the comparison baseline, not a measured zero (REF-941, B+, training logs, running only) |
| 4-6 days | Resume as written; first day back easy, the first key session on day 2 or 3 | Practice; still inside the short-stop baseline of REF-941. SYNTH-36 uses the same cut-off: under a week is a rest; this card and that one step back from day 7, where REF-941 starts to measure a cost (the cut-off itself is the base's convention) |
| 7-14 days | Step back: repeat the last completed week or start below it, then continue; in a marathon build, re-set the goal instead of chasing the lost training | In recreational marathoners a complete stop of ≥ 7 days went with a 5-8% slower finish than the same runner's undisrupted marathon, more when late in the build (5.2% vs 4.4%) (REF-941, B+, observational: the cause of the stop travels with it). In 6 well-trained runners 15 days of detraining cut VO2max 4% and time in an intense submaximal run 25%; 15 days of retraining restored VO2max but performance was still 9% below (REF-164, B, no control). The step-back size is practice |
| 15 days or more, or any illness | Go to SYNTH-36 | 7 endurance-trained people lost 7% of VO2max in 21 days of inactivity, and oxidative enzymes fell with a half-time of ~12 days (REF-377, B). Reduced, not stopped: 21 recreational runners held to <2 h/wk after a marathon lost 6.0% of plasma volume and 10.3% of left ventricular mass within 4 wk (REF-942, B, uncontrolled) |
When to write the week off. Not from a study; the base's own practice: if three or more days are gone, or both key sessions are, stop rearranging. Use what remains for one key session with a clean day before it plus easy work, and start the next week as planned.
What must not be created by rearranging (all Tier 1-3, practice unless cited): two key sessions on adjacent days; a long run within 48 h of intervals; a lift in the 24 h before a quality session (SYNTH-31); strength and endurance in one session when they can sit ≥3 h apart — the explosive-strength penalty of concurrent training was concentrated in same-session designs (REF-330, A, healthy untrained-to-active adults — transfer); a weekend carrying the whole week.
How to progress / periodise
When NOT to use it / red flags
What the evidence does and does not show
Evidence gaps
How this entry was checked and changed
(cessation studies with n=6-7 and a narrative review for the time course, B/B+; a B+ narrative review of general populations for the maintenance dose; B+ runner cohorts for the spike; a B+ log analysis of recreational marathoners for stops of a week or more; a B crossover for three short nights; an A- meta-analysis for sleep; the triage itself — what to drop, where to move, when to write the week off — is house practice that no trial tests)