SYNTH-52 · Guide
Preparing for a sprint or Olympic-distance triathlon
One key session per sport, the hours split by where the minutes are lost, the run rehearsed off the bike, and the bike paced for the run; the base holds no short-course triathlete training-volume study, so the split is practice
The question it answers
An athlete has a sprint (~1-1.5 h) or Olympic/standard-distance (1.5 km swim, 40 km bike, 10 km run per REF-538; the durations are the base's own estimate, ~2-2.5 h for most age-groupers) triathlon: how to split limited hours, which session carries each sport, and how bricks, transitions, strength, taper and fuelling fit. 70.3 and Ironman are out of scope: they are covered by [SYNTH-57].
What decides the result
Draft-legal (elite) racing: across 10 men's and 10 women's World Cup races the winner left the water in the first pack in 90% (men) and 70% (women) of races, while final placing correlated with the run (r 0.86 men / 0.85 women) more than the bike (0.67) or the swim (0.49 / 0.39) (REF-658, B, observational, elite — transfer to age-group racing is inference).
Non-drafting age-group racing is a different event: age-group athletes ride the bike leg as an individual time trial, so the bike's demands and its effect on the run differ from the elite format (REF-538, B+, narrative review, 2002). The same review: drafting lowers bike cost and the saving improves the run; cycling after swimming is usually unaffected except high-power surges early in the bike leg.
Fitness is sport-specific: VO2max and threshold adaptations are specific to the trained mode, transfer is likely greater from running to cycling than the reverse, and heart rate differs between modes (REF-537, B+, narrative review) — set zones per sport; copying cycling HR zones to running is the entry's inference, not a tested rule.
The swim is usually a technique problem: propelling efficiency was 61% in elite swimmers versus 44% in triathletes, and mechanical power output changes dramatically with training (REF-534, B+, 1992 narrative review; a group contrast, not an intervention). Inference: for an adult-onset swimmer the efficiency gap is usually the larger lever.Elite short-course specialists differed from long-course ones only by a faster swim, not in cycling or running physiology (REF-838, B, 15 World Championship men).
Default (what to prescribe first)
For a healthy Tier 1-3 age-grouper with 6-10 h a week and more than ~12 weeks to a non-drafting sprint or Olympic race:
Sessions, not percentages. Not from a study; the base's own practice: 2-3 swims, 2-3 rides, 2-3 runs and 1-2 short strength sessions; at the bottom of the range 2/2/2 plus one strength session. Extra hours go to the discipline that costs the most minutes against the goal (SYNTH-42, framework rule), within the run's injury ceiling (below).
One key session per sport, the rest easy — counting hard sessions across all three sports. Not from a study; the base's own practice: SYNTH-26's budget (two quality sessions at 5-8 h, itself practice) is per athlete, not per sport, so under ~8 h only two are truly hard and the third key session (usually the swim) is controlled threshold or technique work.
Run: the 5-10 km framework's key sessions — threshold and vVO2max-speed work (SYNTH-47).
Swim: threshold repeats and technique.The concept behind critical swim speed was validated in 9 trained college swimmers: critical velocity tracked the lactate-onset speed (r = 0.949) and 400-m speed (r = 0.864) (REF-874, B; six flume speeds); the two-distance pool version: critical speed from 200- and 400-m tests overestimated 30-min speed by 3.2%, not a significant difference, in well-trained competitive swimmers (REF-931, B; sample size not in the abstract), and in 8 well-trained swimmers it sat above the maximal lactate steady state (92.7% vs 88.3% of maximal aerobic speed; REF-932, B) — age-group triathletes are transfer; the swim framework is SYNTH-74; REF-535 (B+, narrative review) stresses accurately defined intensity domains for swim training.Not from a study; the base's own practice: pace from a 400 m + 200 m test, 100-200 m repeats around it with short rest; track distance per stroke, a field proxy for propelling efficiency per REF-534.
Heavy strength twice a week for run economy: in 15 triathletes over 14 weeks, two heavy sessions a week added to the same endurance training improved maximal strength and running economy versus endurance only, VO2max unchanged (REF-082, B, small controlled trial, no economy magnitude). Programme and dose → SYNTH-44 (runners) / SYNTH-43 (cyclists); jumps → SYNTH-45; placement relative to key sessions → SYNTH-31.
Decision
| Situation | Do this | Source and how sure |
|---|---|---|
| Non-drafting age-group race (most sprint/Olympic events) | Train and pace the bike as a time trial, as evenly as the course allows; the run is paid for by bike pacing | REF-538 B+ (format difference); REF-831 B: 12 well-trained men, 1 h at the same mean 65% MAP — a 40-140% MAP ride slowed the next 9.3-km run 42 ± 37 s vs steady, most of it in the first half |
| Draft-legal race (elite; some age-group sprints — not from the base, check the race rules) | Swim-start and pack speed to make the front group; bike-handling to hold a wheel; the run decides | REF-658 B (elite, observational); REF-657 B (10 national-level men: continuous drafting vs sharing the lead cut bike VO2 49.9 vs 59.8 mL/min/kg; 5 km run 17.87 vs 17.15 km/h); pack skills = house practice |
| Adult-onset swimmer, swim is the slowest leg | Technique and efficiency first, swim-specific power alongside; distance per stroke as the marker | REF-534 B+ (61% vs 44%); technique-first order = inference |
| Swimmer or cyclist adding running | Running-specific work is needed; keep week-to-week run increases under 20%; add axial loading | REF-537 B+ (transfer likely greater running → cycling than the reverse); REF-623 B+ (261 recreational runners: 20-60% jumps → ~23 points more injuries at 21 days, no difference at 8-14 weeks); REF-522 C+ (cyclists and swimmers often have lower BMD; axial loading is that entry's house practice) |
| Under ~6 h a week | 2 swims, 2 rides, 2 runs; one ride ends in a short run so the brick costs no extra day | House practice; SYNTH-26 (sessions, not percentages, at low hours — itself practice) |
| Masters | Keep the intensity; widen the gaps between hard days on what recovery shows, not on age; keep strength in season | SYNTH-35 B; SYNTH-44 masters row |
| Women | Same programme; do not restructure around cycle phase; for a hot, humid race in the luteal phase, buy back the thermal margin rather than cut the session | SYNTH-37 B+; SYNTH-44 women row; REF-208 studied men; the REF-082 entry does not give its triathletes' sex |
How to progress / periodise
More than ~16 weeks out: work the missing stimulus in the discipline that costs the most minutes (SYNTH-42; its horizons are house defaults).
Last ~8-12 weeks — rehearse the transitions. Across 39 studies running after cycling was mostly slower than a control run, the physiological and biomechanical reasons conflict, and whether cadence or intensity manipulations help the run is unclear (conflicting evidence) (REF-655, A-, systematic review without pooling; no brick-training intervention summarised).In 9 well-trained triathletes, 20 min at 60, 80 or 100 rpm gave indistinguishable 3 km run times, all 7-9% slower than an isolated run (REF-656, B, crossover).In 7 elite triathletes neither an easy nor a hard ride changed running economy or muscle recruitment (REF-539, B; its abstract notes cycling does impair recruitment in some highly trained triathletes), and a 2000 review puts the added energy cost of running after cycling at 1.6-11.6%, smaller in better athletes (REF-589, C+).So: rehearse the run off the bike as its own demand, at the cadence you race best at. Not from a study; the base's own practice: one brick a week (bike followed by a 10-20 min run, the first minutes at race effort), plus swim → bike rehearsals with a hard start for draft-legal racers (REF-538's practice line).
Transition skills and open water: no entry covers T1/T2 skills; wetsuits and swim drafting improve performance (REF-538); over 400 m in a pool a wet suit cut 8 triathletes' time by 19 s and left 8 competitive swimmers' unchanged (REF-938, B; do not scale to race distance — SYNTH-74); the dedicated wetsuit review has no abstract (REF-835, C).Not from a study; the base's own practice: rehearse wetsuit removal, mounts and open-water starts inside easy sessions, not only on race day.
Taper → [SYNTH-34]. Across 27 studies in competitive athletes the best taper lasted 2 weeks, cut volume 41-60% exponentially, and kept intensity and frequency (REF-107, A, mixed sports). SYNTH-34 allows shorter for a small event (house reasoning). In 8 highly trained pool swimmers a 4-week taper improved competition performance 2.32% (REF-536, B, uncontrolled); not stopping swimming entirely is that entry's house practice.
Race-day fuelling → [SYNTH-02]. Sprint (<90 min): 30-60 g/h from about 1 h in the base's matrix, small amounts or a mouth rinse for shorter races (that row follows consensus, not practice — SYNTH-02); around 1 h of sustained high intensity, small amounts or a mouth rinse help (REF-066, B+, 2011 IOC consensus review).Olympic (~2-2.5 h): the matrix's 90 min-3 h amateur cell is 60-90 g/h (base practice), above the review's 30-60 g/h for longer events and up to 90 g/h beyond 2.5 h (REF-066) — start low unless the gut is trained (SYNTH-02 gut ramp).About 2 h at 60% VO2max is where significant GI disturbance appears, worse with running and heat (REF-525, A-); inference: an Olympic distance sits at that edge. Not from a study; the base's own practice: take most of it on the bike and rehearse the products in bricks.
Race pacing: a slightly easier swim has been shown to help the bike and run, and energy can be saved without losing speed (REF-834, C+, narrative, no numbers); a surging bike costs the run at the same mean power (REF-831).Not from a study; the base's own practice: controlled first minutes of the swim, an even bike held below the effort that wrecks the run, and run targets set from brick rehearsals, never from fresh-run pace (the 7-9% gap in REF-656 was one lab protocol, not a race prediction).
When NOT to use it / red flags
Open water is a safety problem, not a comfort one: water-temperature limits rest on little evidence, acclimatised swimmers cannot judge their own thermal state, and cardiac events appear to be the main cause of death in open-water events (REF-654, B+, narrative review). Not from a study; the base's own practice (that entry's practice line): chest pain, palpitations or breathlessness out of proportion in the water → out and a doctor, not a harder next session.
Hard block, faster heart-rate recovery, performance down, high fatigue: in 31 male triathletes only those who became functionally overreached showed faster HRR during overload (REF-208, B+) — read the combination, not HRR alone.
A 20-60% weekly jump in running raises early injury risk (REF-623, recreational half-marathon runners — transfer to triathletes is inference).
Do not use this framework for 70.3 or Ironman — that is SYNTH-57.
What the evidence does and does not show
Does not: say how to split hours across sports, which intensity distribution triathletes need, whether bricks train the transition away, what bike pacing is best beyond "evenly" (REF-831, one lab protocol), or what a wetsuit is worth over a race distance (REF-938 is a 400-m pool test) — all labelled practice or inference above.
Most triathlon entries date from 1992-2014 (REF-655, 2022, excepted) and studied men or elites; the women and masters rows borrow general frameworks.
Evidence gaps
Cross-sport transfer in age-groupers, the core of the hours split; REF-785 is 4 elites.
Brick sessions as a training intervention; bike pacing beyond one 1-h lab crossover in 12 men (REF-831).
Transition skill and time; women and masters triathletes — nothing triathlon-specific.
Triathlon injury incidence and prevention: REF-832 (C+) documents the gap.
How this entry was checked and changed
Why this level
(race determinants and the brick effect rest on one A- review REF-655, B+ narrative reviews and small B experiments, several elite; the hours split and brick dose rest on no triathlon study; bike pacing on one lab crossover, REF-831)
Content correction 2026-09-27
Revision 2026-09-29: folded in REF-831 (Etxebarria 2013, B: a surging 1-h ride slowed the following 9.3-km run 42 ± 37 s at the same mean power) — the non-drafting Decision row now rests 'ride evenly' on it instead of on inference, and race pacing cites it; REF-874 (Wakayoshi 1992, B) replaces 'no study validating critical swim speed' with the flume validation of the concept; REF-834 (C+) and REF-835 (C, no abstract) into race pacing and transitions; REF-838 (Millet 2003, B) into what decides the result; REF-832 (Gosling 2008, C+) as the injury-evidence line.Stale gap candidates replaced (Millet 2002 is already REF-785). Level unchanged (B-): the hours split is still practice.
Revision 2026-09-29: the long-course exclusion now points to SYNTH-57.
Verification 2026-10-01: all 27 cited REF entries and the pointed-to lines of SYNTH-02/26/34/35/37/42/44/57 read in the KB.md snapshot. Every number attached to a refId (REF-658, 657, 831, 656, 589, 623, 874, 107, 536, 066, 525, 534, 208, 838) matches its entry; levels and designs next to refIds match the head blocks.
Verification 2026-10-01: the weekly split, brick dose, swim test protocol and race-pacing prescriptions are all labelled practice in the same sentence — no UNLABELLED finding.
Verification 2026-10-01: the defects are stale absolute statements left after the 2026-09-29 fold-ins (lead/title 'no entry measures...', question-section 'no long-course training design', Level line 'pacing rests on no triathlon study') that now contradict REF-784/785/831 and SYNTH-57 cited further down.
Verification 2026-10-01: LEVEL-OVERALL has no pair — regrading is the owner's call; suggested C+ for the Default.
2026-10-01: stale lines brought up to the base. Critical swim speed: the two-distance pool test now cites REF-931 and REF-932 (well-trained swimmers; triathletes are transfer) and points to SYNTH-74, instead of 'only the flume concept is validated'.Wetsuit: REF-938 (19 s over 400 m in 8 triathletes, pool) replaces 'the base holds no verified number'; the evidence-gap line narrowed to race distance. Sprint fuelling row relabelled: SYNTH-02's <90 min row is consensus, not practice. The 70.3/Ironman exclusion already points to SYNTH-57 in the live text.
2026-10-02: aligned with the rewritten SYNTH-42 (missing stimulus, one lever per block, level C+): the pointer "SYNTH-42 labels this ordering as inference too" is dropped (SYNTH-42 no longer has a swimming row; the sentence stays labelled inference here); "work the limiter of the discipline" -> "work the missing stimulus in the discipline"; cross-reference label.