Preparing a Triathlon — Sprint to Ironman, Weekly Hours, Swim/Bike/Run Split, Bricks, Long Sessions and Taper

A triathlon is three endurance races in a row — swim, bike, run — with two transitions. Each leg is ordinary on its own; what makes the sport is the sequence (the run is run on legs that have just ridden) and fitting three sports into one week. The fitness that wins is mostly aerobic. The plan that gets there is mostly allocation: how many hours, how they split among the sports, which sessions are hard, and how fatigue from one sport spills into the next.

This document covers a first sprint to an Ironman: what each distance asks for, readiness and length, weekly hours and their split, the week over four to seven days, bricks, long sessions, taper and fuelling. The run sessions themselves are those of the running race documents; zones and polarized training are in the general endurance document.

What Each Distance Demands

Distance	Swim	Bike	Run	What decides it
Sprint	750 m	20 km	5 km	speed near threshold in all three; the run off the bike
Olympic (standard)	1.5 km	40 km	10 km	threshold power on the bike, a 10 km near threshold on tired legs
70.3 (half distance)	1.9 km	90 km	21.1 km	a controlled ride well below threshold, then a half marathon
Ironman (full distance)	3.8 km	180 km	42.2 km	durability, pacing at the first threshold, fuel

Many local races use a pool swim of about 400 m with a sprint bike and run: the usual first race. Age-group races are ridden as individual time trials; drafting on the bike is for elite short-course racing, and a wetsuit, where allowed, makes the swim faster than in the pool.

Short course: hard from the gun

A sprint lasts about an hour for the best athletes and longer for most age-groupers; one group of recreational athletes finished a standard-distance race in about 2 h 40 min. Both are short enough to be raced hard throughout. For recreational athletes the run weighs heavily: the best laboratory predictor of standard-distance time was peak running speed, and the 10 km comes after 40 km of hard riding, which raises the cost of running.

Long course: below threshold, fuelled

At the 70.3 the bike is the largest block and, across large datasets, the strongest predictor of the result. At the full distance the ride and the marathon are held at about the first ventilatory threshold: in well-trained athletes race heart rate on bike and run matched it, well below the second, and those who rode furthest above it ran the slowest marathons. The full distance is limited by durability and fuel, not speed; among professionals the run predicts the result best, because it is where the cost of the swim and the ride is paid.

The bike is half the race

In 184 recreational men at a full-distance race the swim took 76 minutes, the ride 349 and the run 257, of 691: about 11% swim, 50% bike, 37% run, 1% transitions. Among professionals, cycling is the largest share of race time at every distance, swimming the smallest, and running grows with distance.

Starting From Zero: The First Sprint

The swim is the usual limit, and the safety question

• Most deaths happen in the water. Of 120 sudden deaths and cardiac arrests in US triathlon participants, 90 happened in the swim, 7 on the bike, 15 on the run and 8 after the finish. Victims averaged 47 years, 85% were men, and silent heart disease was common. The race sudden-death rate is about 1.5 per 100,000 participations, mostly in the swim. A medical check before a first race makes sense from about 40, and at any age with symptoms or risk factors.
• Swimming borrows nothing from the other two. In elite triathletes, cycling training carried over to running but neither carried over to swimming. A fit runner who cannot swim freestyle is a beginner.
• Swim competence comes first. Without 50 m of continuous freestyle, start with technique lessons and short repeats two or three times a week. Three weeks before an open-water race the athlete swims the race distance continuously with some to spare, and has swum in open water several times. A pool-swim sprint, or a calm lake, is the sensible first race.

Frequency first, in all three

• Two sessions per sport per week — six short sessions over four to six days — builds swim technique and run tissue tolerance faster than fewer long sessions.
• The run starts as run/walk for non-runners, as for a first 5K. Novice runners get injured more than twice as often per hour as recreational runners, and running is where most triathlon injuries happen.
• The bike is the easiest to build: no impact, so it takes the extra time.
• No intervals in the first weeks; strides, cadence spins and relaxed swim repeats come once each sport is continuous.

A first sprint is a completion goal. In coaching practice it takes 10–16 weeks from no regular exercise, 8–12 from a base in one or two of the sports.

Before the Block: Readiness and Length

Readiness

A distance block should start from a base, not create one. These coaching-practice minimums are consistent with what finishers report; below them, the first weeks are base in the weak sport.

Goal	Swim, continuous	Bike	Run	Weekly training
Finish a first sprint	comfortable in water, building to 750 m	30 min	20 min run/walk	2–3 h
Sprint time goal, or a first Olympic	750 m	60 min	30 min	3–5 h
70.3	1500 m	2 h	60 min	5–7 h, after a sprint or Olympic
Ironman	2000 m	3 h	90 min	8–10 h, after a 70.3, or an Olympic and a marathon

• A shorter race first. Four in five recreational full-distance finishers had done a standard-distance race, and their best time there was one of the two strongest predictors of their full-distance time. A previous best 70.3 was among the best predictors of 70.3 time.
• Hours alone do not make the athlete. The fastest 70.3 finishers did not train more hours than slower ones; they had more race experience and took fewer rest days.

How long the preparation lasts

Situation	Sprint	Olympic	70.3	Ironman
First race at the distance, with a base in all three	8–12 weeks	12–16	16–24	24–32
Experienced at the distance or longer	6–10	10–14	12–20	16–24
Low current volume, returning, or 50+	+4	+4	+4–6	+4–8

These are coaching practice; recreational full-distance athletes with years in the sport reported about 21 weeks of specific preparation, with a wide spread. The plan is built backwards from race day: taper on the race, race-specific weeks before it, base in whatever time is left.

Weekly Hours

What age-group triathletes do

• Olympic. Recreational athletes averaged about 8 h 50 min a week over a year (3 h 30 min to 13 h 30 min), in about 2.2 swims, 3 rides and 2.7 runs; about 6 hours a week before their race.
• Full distance. Recreational men trained 13.9 ± 5.0 hours a week (6.3 km swim, 194 km bike, 45 km run) for about 11 h 30 min. An older survey found 8.8, 270 and 58 km a week — roughly 15 hours — for about 11 h 45 min, and concluded that finishing needs less training than elite studies suggested.
• 70.3. Trained masters preparing a 70.3 trained about 14 hours a week; evidence specific to the distance is thin, mostly small heterogeneous samples.
• Elite. A world-class Olympic-distance athlete averaged 16 sessions a week: about 25 km swimming, 9 hours cycling, 5 hours running.
• Injury. In non-elite triathletes injury was least likely at 8–10 hours a week, with 5–6 hours cycling and 3–4 running; both less and more went with more injuries, and in another survey injury rates rose with weekly training time.

Typical peak weekly hours

Goal	Sprint	Olympic	70.3	Ironman
Finish a first race	3–5	5–7	7–10	10–13
Recreational time goal	4–6	6–9	8–11	11–14
Trained age-grouper	5–8	8–11	10–13	13–16
Competitive age-grouper	7–10	10–14	12–16	15–20

Coaching-practice peaks in the last weeks before the taper, consistent with the data above — not starting points. An athlete starts from the hours actually trained recently, sport by sport.

Progression

• Steps under about 10% a week, with a lighter week every third or fourth that cuts volume by 20–30%, keeps the number of sessions and shortens the long ones. Spikes are the problem: every recreational triathlete followed before an Olympic race doubled their load from one week to the next at least once, and large spikes raise injury risk for weeks.
• Each sport progresses from its own base: a strong cyclist who never ran starts the run at run/walk.
• Reach the peak and hold it two to three weeks before the taper; long-course plans reach it four to seven weeks out.

Splitting the Hours Among Swim, Bike and Run

Distance	Swim	Bike	Run
Sprint	20–25%	40–45%	30–35%
Olympic	20–25%	45–50%	25–30%
70.3	15–20%	50–55%	25–30%
Ironman	12–18%	55–60%	25–30%

Coaching practice, matching what athletes report: recreational Olympic athletes about 27% swim, 43% bike, 27% run; the full-distance survey about 17%, 55%, 28%.

Why the bike gets the most

1. It is half the race, more at the long distances.
2. It is the cheapest aerobic volume. Cycling has no impact; running is where overuse injuries cluster. Half of all injuries in non-professional triathletes happened running and 7% swimming (seven in ten running in another survey); high running mileage predicted injury; in full-distance athletes overuse problems affected over half at any time, mostly knee, lower leg and lower back.
3. It carries over. In elite triathletes cycling training improved running performance: bike hours build the engine the run uses without the run's tissue cost.

Why the swim gets sessions, and the run a cap

The swim is the shortest leg and its fitness does not transfer, so it is trained by frequency and technique — two or three sessions a week at every level — more than hours; swim time did not affect injury risk. The run decides long races but its volume is limited by injury risk: two to four sessions, mostly easy, never more weekly time than a running plan for the same distance would hold.

The weakest discipline can take about five points from the bike; a first-timer limited by the swim can spend a quarter or more of the time in the water. No discipline drops below two sessions a week.

The Week: Four to Seven Training Days

Training days	Swim	Bike	Run	Days with two sessions
4	2	2	2, plus a short run off the bike	2
5	2	2–3	2–3	1–3
6	2–3	3	3	2–3
7	3	3–4	3–4	3–4

• Four days suit a sprint or an Olympic; a 70.3 only for a finishing goal; a full distance needs five, better six.
• Anchor days: the long ride, usually at the weekend with a short run after it, and the long run.
• A full rest day for beginners, recreational athletes and masters; trained athletes on seven days make one day a short easy swim.

Two sessions in a day

Three sports at two sessions each need six sessions; on fewer days, some carry two.

• Swim plus run or swim plus bike first: different muscles, and the swim has no impact. An easy ride and an easy run on the same day suit trained athletes only.
• At least six hours apart when both matter; back to back only as a brick.
• One hard session a day at most; the brick counts as one.
• Strength at least three hours after endurance work: concurrent training costs explosive strength mainly when both share a session.

Elite triathletes train two or three times a day, but how much the sessions' signals interfere is not known. For age-groupers a double is a way to fit the week, not a goal.

Keeping the hard sessions apart

• No hard bike and hard run on consecutive days: cycle and run training add up as one cumulative stress on injury risk.
• The long run never follows a hard run; run quality sits 48 hours from the long run.
• Swim quality can sit next to a land session, including the day after a hard bike or run.
• Long ride and long run on consecutive days are fine at the short distances, where both are easy. At 70.3 and full distance — the "big weekend" — only for trained athletes in race-specific weeks.
• The day after the longest day is easy or off.

Bricks: Running Off the Bike

Running straight after cycling costs more: the energy cost of running rose 1.6–11.6% after a 40 km ride, depending on level, with a more forward-leaning trunk. A 12-minute maximal run after a 20-minute time trial covered 5.8% less distance than the same run fresh, with shorter strides.

Evidence that bricks build fitness is thin. Elite triathletes use them less than expected, and the one training study of repeated cycle-run sessions over six weeks did not improve cycle-run performance, though the transition improved. Bricks are rehearsal — the feel and pacing of the first kilometres, fuelling, the transition — and cheap when the run is short.

Distance	Build phase	Race-specific weeks
Sprint, Olympic	10–15 min easy after a ride	15–20 min, the first 10 at race pace
70.3	15–20 min easy after the long ride	20–45 min at 70.3 effort after the long ride
Ironman	15–20 min easy after the long ride	30–60 min at Ironman effort, every other week

One brick a week from the build phase (beginners every other week), none in the base. The run counts in the week's running, stays well under the long run, and is never the day before a key run.

Key Sessions by Discipline and Block

As in the running race documents, the weeks before the race-specific block split into base and then build. In coaching practice the race-specific block is the last 4–6 weeks before the taper for a sprint or an Olympic, 6–8 for a 70.3 and 8–10 for a full distance.

Block	Swim	Bike	Run
Base	drills, aerobic repeats (8–12 × 100 m), one longer swim	endurance, cadence spins, short hill repeats	easy, strides, a 20–30 min tempo from recreational level
Build	threshold repeats (5–10 × 100–200 m at 1500 m pace)	short course: threshold 2–3 × 8–20 min; long course: tempo 2–3 × 15–30 min	short course: threshold and VO2max intervals; long course: threshold or tempo
Specific	race-pace repeats (3–5 × 300–500 m), open water	short course: race-pace intervals; long course: race-effort blocks in the long ride	race pace off the bike; long course: short steady segments
Taper	short race-pace touches	short race-pace touches	short race-pace touches, strides

• Swim tolerates more intensity: the world-class Olympic athlete did about 10% of her swimming above the onset of blood lactate accumulation, against 2% of cycling and 7% of running.
• Bike hill repetitions went with fewer overuse injuries in Olympic-distance athletes; in full-distance athletes more time in fast run and bike sessions went with more.
• Run sessions follow the running documents for the leg's distance, with less volume.

Intensity Across Three Sports

Mostly easy, in every sport

• The world-class Olympic athlete did 74%, 88% and 85% of swim, bike and run below lactate threshold.
• Full-distance age-groupers spent about 69% of training below the first threshold, 25% between the thresholds, 6% above. In another group, more time in the easiest zone went with faster full-distance times and much moderate cycling with slower ones — although the race itself is mostly in that zone.
• Recreational 70.3 athletes prepared on a polarized (about 85/4/11) or pyramidal (78/19/3) distribution, and moderate-zone time went with better times on some legs: race-effort work belongs in the last weeks of long-course plans.
• Recreational triathletes before an Olympic race trained at high overall intensity with large weekly swings, and more time at high intensity went with smaller gains, or losses, in their tests. Easy sessions done too hard are the commonest way a triathlon plan fails.

Fatigue adds up across the sports

Bike and run share the legs and add up as one stress; triathletes who train around an injury by moving load to another sport may make recurrence more likely. The swim adds little, so swim quality can sit next to a hard land day. Hence one budget of hard sessions for the week, not one per sport:

Level	Hard sessions a week, all sports	Bike and run at most
Beginner, first race	0 in the first weeks, then 1	1
Recreational	2	2, one run
Trained	3	2, one run
Competitive	3–4	3, two runs

Long Sessions

The long ride builds durability for bike and run: in a full-distance field, weekly cycling distance and the longest training ride were, with the Olympic best time, the best predictors of the finish. Recreational Olympic athletes' longest sessions were a little over three hours on the bike, under two running and about 75 minutes swimming.

Distance	Long ride, peak	Long run, peak	Longest swim session
Sprint	60–105 min	40–70 min	1000–1500 m
Olympic	1:30–3:00	60–90 min	2000–2500 m
70.3	2:30–4:00	80–110 min	2500–3000 m
Ironman	4:00–5:30	1:45–2:30	3500–4000 m

Coaching-practice caps, first-timers at the low end. The long ride grows about 15 minutes per loading week, the long run 10, the longest swim 100–200 m; all are shortened, not dropped, in lighter weeks. The longest rides fall three to six weeks before a full distance, three to five before a 70.3. By race day the athlete has swum the race distance continuously; more swimming adds little where the swim is a tenth of the race.

Why the long run is capped lower than for a marathon

A marathon plan takes the long run to 2:30–3:00; a full-distance plan stops at about 2:30, and a 70.3 plan below the half marathon's two hours:

1. The race run is slower. The recreational men above ran their full-distance marathon in 257 minutes, a third slower than their best open marathon of about 194: durability matters, not pace.
2. The bike supplies the endurance, and its aerobic gains carry over to running without impact.
3. Running is where the injuries are, and a three-hour run costs days in which two other sports need key sessions.
4. Brick runs add running on tired legs every week of the specific block.

Open Water and Transitions

• Practise open water. Training is in a pool; races are in lakes or the sea, with no walls or lane lines, cold water, waves and mass starts. Several open-water swims in the last six to eight weeks, never alone, sighting every few strokes.
• The wetsuit, where allowed, is faster — by up to about 11% — through buoyancy and less drag, with a gain that depends on ability and suit; many find it uncomfortable at first. Train in it first.
• Swim within yourself. A lower swim intensity can help the bike and run without losing much swim speed. Full-distance athletes swam at a higher relative intensity than they rode or ran, and those with the largest swim-to-bike heart-rate gap had the worst later legs.
• Transitions took about nine minutes in all for the recreational full-distance men above, a few minutes in a sprint. Rehearse them: kit layout, wetsuit removal, the bike-to-run change in bricks.

Pacing the Race

• Swim even, as athletes did across sprint, Olympic and half-distance races.
• Ride below what feels possible. At the full distance well-trained athletes rode at a heart rate near the first threshold, and the power they chose for a five-hour ride was about 70% of their threshold power. Even athletes in the top tenth of a field saw power fall about 15% over a flat 180 km.
• Start the run controlled: in Olympic and half-distance races athletes started fast and slowed.

Estimating a Finish Time

A recent race at the same distance is the best guide: a previous best 70.3 was among the best predictors of 70.3 time, and recreational full-distance time was predicted by the best Olympic time together with the best open marathon. Without one, the legs add up — a rough estimate:

• Swim: continuous pool pace over at least 400 m, times the distance; open water costs sighting and navigation (about 5% in coaching practice), and a wetsuit gives some of it back.
• Bike: the average speed of a steady solo ride of one to two hours on flat roads, a little faster at the short distances; recreational full-distance men rode the race faster than they trained.
• Run: the open-race time for the leg's distance, slowed by the bike: about 6% at the sprint and Olympic distances, about 15% at the 70.3 (a coaching estimate between the measured cases) and about a third at the full distance.
• Transitions: a few minutes at the short distances, about ten at the full.

A goal much faster than the sum is ambitious; the race-pace sessions and bricks of the last weeks show whether it holds.

The Taper

• About two weeks, volume cut 41–60%, intensity kept: the best-supported taper in endurance sports. In triathletes a 41–60% cut brings physiological and performance gains; intensity is kept to retain adaptations, and frequency above about 80% of normal avoids detraining and loss of feel. The best length varies between athletes, from 4 to 28 days.
• Progressive, not a step: in triathletes a fast exponential taper beat a step reduction.

Distance	Race −2 weeks	Race −1 week	Race week, before the race
Sprint	—	about 80%	about 50%
Olympic	—	about 75%	about 50%
70.3	—	about 70%	about 45%
Ironman	about 80%	about 60%	about 40%

Volumes are shares of the peak week. Each week keeps short race-pace work in all three sports and about the same number of sessions, each shorter; the long sessions shrink with the volume, to about half to two thirds of their peak in the week before race week. The last long ride is two weeks before a full distance, at about two thirds of the peak; race week is a short swim, ride and run with a few minutes at race effort.

Fuelling for 70.3 and Ironman

• Carbohydrate. About an hour needs little; two to three hours up to about 60 g per hour; ultra-endurance about 90 g per hour from glucose–fructose mixtures. Age-groupers at two full-distance races and a 70.3 took 62–71 g per hour on average, with a huge range; more went with faster full-distance times but also more nausea.
• Mostly on the bike. Nothing is eaten in the swim; the bike is where eating is easiest, and the run has the most dropouts, mainly for stomach problems at the full distance.
• Train the gut. Two weeks of repeated carbohydrate intake in training reduced gastrointestinal symptoms and improved performance: rehearse race intake in every long ride and brick.
• Before the race: 10–12 g/kg of carbohydrate a day for 36–48 hours; 1–4 g/kg one to four hours before the start.
• Fluids. Drink to thirst: drinking well beyond it over many hours causes exercise-associated hyponatraemia. Sodium is worth considering with a history of cramps; about 3 mg/kg of caffeine helps alertness with few side effects.

Strength Training for Triathletes

• Economy without mass. In long-distance triathletes, 26 weeks progressing from 8–12 repetitions to heavy 1–6 (85% of 1RM or more) improved cycling and running economy without adding body mass; two heavy sessions a week for 14 weeks improved strength and running economy in triathletes. Heavy work helps cycling economy; heavy or explosive work helps running.
• Injury prevention. Strength training is the most effective exercise intervention against overuse injuries; for triathletes, protect knee, lower leg, lower back and shoulder.
• Dose and placement. Two sessions a week of 2–3 sets of 4–10 repetitions at maximal intended speed in base and build; one in race-specific weeks; none in race week. Upper-body pulling serves the swim. On a light day or after easy work, never the day before the long ride, long run or run quality.

Masters Triathletes (45 and over)

• The run and swim decline first. Endurance performance changes modestly until 50–60, then falls faster, mostly through VO2max. Cycling declines less with age than running and swimming, and long races more than short. Older age-groupers in Hawaii improved over 25 years: much of the decline follows the lower training volume and intensity of older athletes.
• Recovery feels slower: masters cyclists recovered performance as fast as young ones after hard intervals but reported fatigue and soreness for longer.
• Rules: a lighter week every third week; at most two hard bike or run sessions, swim quality on top; strength kept; four or more extra weeks of preparation; a medical check before a first race and before moving up to long course — race deaths cluster in middle-aged and older men.

Common Mistakes

• Easy sessions done moderately hard in all three sports.
• Hard bike and hard run on consecutive days; run quality the day after the long ride.
• Too few swims, then a panicked first open-water swim on race day.
• Marathon-length long runs at the cost of injuries and of the bike.
• Riding the race too hard and walking the run.
• Never rehearsing fuelling, wetsuit or transitions; no taper, or one that drops all fast work.

Key Takeaways

1. Swim competence and a medical check first; a first sprint is a 10–16-week completion goal.
2. Peak hours by distance and level: about 3–10 for a sprint, 5–14 Olympic, 7–16 70.3, 10–20 full.
3. The bike takes about half the time; the swim gets frequency, the run frequency with capped length.
4. Mostly easy in every sport, one budget of hard sessions for the week, hard bike and run never back to back.
5. One short brick a week from the build phase, as rehearsal.
6. Long runs capped at about 2:30 even for a full distance; the long ride carries the durability.
7. Taper about two weeks (three for a full distance), cutting volume 40–60%, keeping intensity.
8. Fuel 60–90 g of carbohydrate per hour in long races, mostly on the bike, rehearsed in training.