Most age-group 70.3 bike splits sit between 2:45 and 3:15. The athletes who drop into the 2:30s rarely do it by finding a bigger FTP. They do it by holding a higher percentage of the FTP they already have, for longer, without blowing the run.
That distinction matters because the 70.3 is not a bike race. It is a 90km time trial sandwiched between a 1.9km swim and a 21.1km run, and the bike leg is the one discipline where ambition most often destroys the day. Ride 15 watts too hard for the first 30km and you will give those watts back at 12 minutes per kilometre on the run.
This 12-week plan is built for the athlete who wants a genuinely faster bike split and still wants to run the back half of the half-marathon. It assumes you already have a training base of 6–8 hours per week and a recent FTP test. If you need one, the FTP zones calculator will set your targets for every session below.
What a realistic bike-split improvement looks like
Let's benchmark honestly. A mid-pack male age-grouper at a rolling European 70.3 rides around 2:55 to 3:05. A mid-pack female rides 3:05 to 3:20. Front-of-age-group riders sit in the 2:25 to 2:40 window. Pro times run 2:05 to 2:20 on fast courses.
Over 12 weeks, a 5–15 minute bike-split improvement is realistic for a committed age-group athlete. A 20 minute gain is possible but usually requires at least one of three structural changes alongside the training: a meaningful position change, a better aero helmet and suit, or a pacing fix from someone who has actually ridden the course. Training alone, without those, tends to produce the 5–10 minute end of the range.
Where do the minutes come from? Roughly a third from raising sustainable power at 75–85% of FTP, a third from pacing discipline (not surging early, not fading late), and a third from fuelling and position durability. Raw FTP gains inside 12 weeks are modest. A well-coached athlete adds 3–7% to FTP in a block this length. That is maybe 8–20 watts for most age-groupers, worth 3–6 minutes on the bike.
The rest of the time is found by holding those watts honestly. John Wakefield, Director of Development at Red Bull-Bora-Hansgrohe, has made the point on the Roadman Cycling Podcast that most age-group athletes are not limited by their ceiling. They are limited by how long they can sit just below it without flinching.
Phase 1: Aerobic base (weeks 1–4)
The first four weeks build the aerobic engine the rest of the plan draws from. Weekly bike volume runs 5–7 hours across three rides, with most of that time at 65–75% of FTP. This is Zone 2, the pace where you can hold a conversation but would rather not.
The structure per week looks like this: one long aerobic ride of 2:30 to 3:30, one mid-week endurance ride of 1:15 to 1:45 with three to four 8-minute efforts at 80–85% FTP, and one short recovery or skills ride of 45–60 minutes. Total bike Training Stress Score targets 350–450 per week by the end of week four.
Prof. Stephen Seiler's research at the University of Agder on polarised training is directly relevant here. Elite endurance athletes spend roughly 75–80% of training time at low intensity, with a small, potent dose at high intensity. The common age-group mistake is grinding the middle — too many rides at 78–85% FTP, which accumulate fatigue without building the aerobic base or sharpening the top end.
Two specific habits to build in weeks 1–4. First, get on the TT bike for at least half of every ride, including the long one. Position durability is trained, not inherited. Second, practise race fuelling now: 70–90 grams of carbohydrate per hour on every ride over 90 minutes. Waiting until the race-specific block is a classic way to meet your gut for the first time at 60km.
If you are coming into this block with run mileage you want to protect, weight the volume towards steady aerobic work and keep the hard bike intervals short. This is where bespoke triathlon bike coaching earns its keep — knowing when to hold the stick back on the bike so the run keeps developing.
Phase 2: Sustainable power (weeks 5–9)
Phase 2 is where the bike split is actually built. Five weeks, three hard and two recovery-loaded, with the work focused on the zone you will race in: 75–90% of FTP. Weekly bike volume climbs to 7–10 hours.
The two anchor sessions each week are a long race-specific ride and a threshold session. The long ride extends to 3:30 to 4:30 and includes 2 × 30 minutes at 80–85% FTP inside it, ridden on the TT bike in race position. The threshold session alternates weekly between 4 × 10 minutes at 95–100% FTP and 3 × 15 minutes at 88–92% FTP, both with 5-minute recoveries.
A third ride each week is a brick: 90 minutes with 30–40 minutes at 78–82% FTP, straight into a 20–30 minute run at target race pace. The brick run is not optional. It is the single best predictor of whether your race-day pacing is honest, because it tells you whether the power you think you can hold actually leaves legs to run off.
Dan Lorang, who has coached Jan Frodeno, Gustav Iden, and Anne Haug, has been consistent on this point: the long ride in the race-specific block should simulate race demands, not just accumulate hours. A four-hour ride with no structured intensity is a base ride. A four-hour ride with 60–75 minutes at race power, fuelled at race rate, is a 70.3 session.
Week 5 and week 8 are recovery weeks. Cut volume 30%, keep one short threshold session to hold sharpness, and sleep. Athletes who skip these weeks reach week 9 unable to hit targets and call it a plateau. It is not a plateau. It is accumulated fatigue masquerading as lost fitness.
Retest FTP at the end of week 9. Most athletes see a 3–7% lift. Update your zones, then carry the new numbers into the taper.
Phase 3: Race-ready taper (weeks 10–12)
The taper is not a rest. It is a carefully managed reduction in volume while maintaining intensity, and it runs three weeks for a 70.3 if you have trained seriously. Athletes with a smaller weekly load can taper in two weeks without issue.
Week 10 is your last big ride. Go 4:00 to 4:15 with 2 × 45 minutes at 78–82% FTP inside it, fuelled exactly as you plan to race. This is a dress rehearsal: race kit, race nutrition, race position, race start time if possible. Anything that goes wrong here gets fixed before race day.
Week 11 cuts bike volume by 25–30% but keeps one sharp session: 5 × 5 minutes at 100–105% FTP, or 3 × 12 minutes at 90–95% FTP. The goal is to keep the neuromuscular system awake. Long slow rides in taper week do not help.
Week 12 cuts volume another 40% from week 11. Three short rides: 60 minutes easy with 3 × 3 minutes at race power on day 1, 45 minutes easy with 5 × 30-second openers on day 3, and 20–30 minutes of easy spinning on race-minus-one. That final spin is for the legs and the head, nothing more.
Dan Bigham, former UCI Hour Record holder, has made the point that the last two weeks before a time trial are for removing friction, not adding fitness. Check your tyres, your cleats, your bolts. Run your fuelling through a spreadsheet and know your carbs-per-hour to the gram. The fitness is already banked.
Key weekly sessions
Across the 12 weeks, three sessions repeat. They are the work that matters most. Every other ride on the plan exists to let you execute these well.
Session 1: The long race-specific ride. 3:00 to 4:30 depending on phase. Built around 60–90 minutes of race-power work split into two or three blocks, ridden on the TT bike in race position, fuelled at 80–100 grams of carbohydrate per hour. This is the session that builds the durability to hold target power in hour three of the race. Skip it in favour of group rides and your bike split will fade in the last 30km.
Session 2: Threshold intervals. Once per week, 45–75 minutes total work time. Alternates between longer sub-threshold blocks (3 × 15 minutes at 88–92% FTP) and shorter threshold efforts (4 × 10 minutes at 95–100% FTP). These raise FTP and, more importantly, raise the power you can hold at 80% of FTP. A higher ceiling lifts the floor you race on.
Session 3: The brick. Once per week from week 5 onwards. 60–90 minutes on the bike ending with 30–40 minutes at race power, straight into a 20–30 minute run at target run pace. No transition faffing. Bike off, shoes on, run. This session is where you learn what your race-day bike power actually costs you on the run.
Two further rides per week fill out the volume at easy aerobic pace and short openers. If your schedule only allows three bike sessions per week, these are the three. Drop the filler rides before you drop the key work.
Joe Friel, author of The Cyclist's Training Bible, makes the point that most age-group plans fail because athletes execute the hard sessions too easy and the easy sessions too hard. The targets above only work if the easy rides stay genuinely easy. Zone 2 means Zone 2, not Zone 2 with your mate who is building for a road race.
Pacing the 90km on race day
Target power for a 70.3 bike leg is 70–78% of FTP for most age-group athletes. That is an intensity factor (IF) of 0.70 to 0.78 and a normalised power that should feel firm but conversational for the first 45 minutes. Stronger runners with a robust FTP can push 0.78–0.82. Above 0.80, the run almost always pays.
Split the 90km into four pacing blocks and the race becomes manageable.
Kilometres 0–20. Cap power 5–10 watts below your target. Heart rate is elevated from the swim and the opening surge of the bike leg, and the watts will feel too easy. They are correct. Most blown 70.3s are decided here.
Kilometres 20–60. Settle into target IF. Fuel every 15 minutes on the clock, 20–30 grams of carbohydrate per feed. Stay aero. If you sit up for anything other than a technical corner or a bottle handoff, you are leaving time on the course for free.
Kilometres 60–80. This is the hardest section. Fatigue is real, the novelty has worn off, and the run is still ahead. Hold power, not perceived effort. A power meter is non-negotiable for this stretch because RPE drifts upward while actual watts drift down.
Kilometres 80–90. Do not sprint to T2. Ease the last 2km by 10–15 watts to let the legs transition. You will lose 15–20 seconds on the bike and gain 90 seconds in the first kilometre of the run.
The athletes who execute this race plan are the ones who ride negative or flat power splits. Positive splits (harder first half than second) almost always produce slower overall times, even when they feel faster on the bike.
If you want this plan built around your power, your race course, and your run limiter, apply for 1:1 coaching through the Not Done Yet programme. Twelve weeks of self-execution from the template above will produce results. Twelve weeks with the plan adjusted weekly to what your power files, your sleep, and your run off the bike are actually telling you will produce more.
