Typical Peak Training Week — 70.3 Build (~22–25 hrs)
Jelle's week under Ben Reszel features a clear hard/easy rhythm that his Joel Filliol years didn't have. Big 5–6 hour training days are offset by genuinely easy recovery days. Bike volume is higher than his ITU years (18–20 hrs vs 13–15 hrs). Run is slightly down (~70K vs 80–100K) but executed at faster easy paces. One swim fewer per week.
The ITU-to-70.3 Transition: Before vs After
The shift from Joel Filliol (ITU/short course) to Ben Reszel (70.3/middle distance) represents one of the most documented and successful coaching transitions in recent triathlon history. Here's exactly what changed.
Under Joel Filliol (ITU)
Under Ben Reszel (70.3)
Intensity Distribution — 70.3 Race Build
Jelle's training is polarised between genuinely easy running and biking and targeted threshold + race-specific blocks. The VO2 component is used periodically but is not a year-round staple. Unlike pure Norwegian double-threshold, the easy days are truly easy — not moderate.
Jelle's Exact Key Sessions
All sessions sourced directly from Jelle's own words in the podcast, supplemented by his published race preparation data. These are the sessions that built back-to-back 70.3 World Championships.
4–5 × (4 × 40 sec hard / 20 sec easy)
Jelle calls this "the hardest session I've done in my whole build." Four reps of 40 seconds at approximately 2:40/km pace (well above 70.3 race pace), 20 seconds easy — repeated four times per set, with a five-minute break between sets. "I got so lactic and that's the pain I don't like." He prefers threshold pain to lactic pain — but acknowledges this session is necessary. Used during base/early build to develop lactate tolerance before transitioning to race-specific work.
4 × 3K (alternating threshold / sub-threshold)
Rep 1 at threshold, rep 2 slightly slower than threshold, rep 3 at threshold, rep 4 slightly slower. Two-minute rest between reps. Done with lactate testing to verify correct zones. Threshold pace is just below 3:00/km; sub-threshold is approximately 70.3 race pace (~3:10/km). "Nothing special or extremely hard" — but accumulates significant physiological stress when all four reps are done correctly. The pattern teaches the body to manage and recover from threshold efforts, simulating the rhythm of a race.
9 × 1K (slow-threshold-fast cycling) + 2K race pace + 400m
The most structurally complex run session in Jelle's build. Three cycles of: 1K just slower than threshold, 1K at threshold, 1K faster than threshold. Then 2K at 70.3 race pace (~3:10/km) followed by 400m faster. The 1K reps above threshold are what makes this hard — "you can really feel it towards the end." Jelle calls this one of the hardest run sessions of his preparations for both major 2024 wins. The final 2K+400 confirms his race pace while fatigued.
Spiked race-pace blocks: 2' hard + 3' strong + 12' settle = 15' sets × 4–5
The signature Ben Reszel race-specific bike session. Designed to replicate T100/70.3 race dynamics — not a steady TT effort but the surges, attacks, and settle-in rhythm of real racing. Two minutes at higher power (surging / following attack), three minutes slightly above race power, 12 minutes settling into sustained race pace. Repeat 4–5 times. Total work 60–80 minutes at race-relevant intensity inside a 3.5–4 hour ride. This corrects a mistake from Jelle's Oceanside build, where all bike work was done at a flat 300–315W with no spikes.
3–4 hr easy ride + 75–85 min long run
The Saturday double is the cornerstone of Jelle's weekly volume. Long easy bike in the morning (3–4 hr at genuinely easy pace), then a long easy run (75–85 min, maximum 4:00–4:15/km). Not a brick in the traditional sense — there is recovery time between them. Together they create significant leg fatigue that prepares the body for race-day conditions without the injury risk of hard back-to-back sessions. The longest run in the build was 85 minutes — notably shorter than many athletes at this level.
Squad sessions + solo sessions · Focus on open-water and pace work
Jelle participates in Triathlon Australia's swim sessions on the Gold Coast, supplemented by solo sessions. Unlike the JR Squad structure (Fred Funk's approach), Jelle's swim focus is more on open-water confidence and race positioning. The swim is his declared weakest discipline — he started swimming at age 15–16 with no childhood background. In short course, this was decisive; in 70.3, it's manageable. Race strategy: exit with the front group, manage the positioning, get on a wheel quickly. The shift to 70.3 means swim gaps are recoverable — his run more than compensates.
Race Day Fuelling — 70.3 World Championships
Jelle's race nutrition from Taupo 2024, verified by Precision Fuel & Hydration. A "front-loaded" strategy: maximise carbohydrate on the bike when time allows, then maintain with gels on the run.
| Phase | Product / Strategy | Carb intake | Notes |
|---|---|---|---|
| Pre-race | White rice + toast + honey + 500ml carb drink + gel on start line | ~150g total | Hits carb guidelines before gun fires |
| Bike (~2 hrs) | 2 × 750ml bottles (120g carbs each) + ~200ml water from aid station | ~120g/hr | Front-loaded — does all heavy carb work on bike |
| Run km 6 | Energy gel | ~30g | First run gel after settling into pace |
| Run km 12 | Energy gel | ~30g | Mid-run top-up |
| Run km 18 | Energy gel (the moment he hit first place) | ~30g | Final push — timed with race surge |
| Total run | 3 gels + water cups for cooling | ~75g/hr | Drop from bike rate is intentional |
4-Week Training Block — 70.3 Race Build
Built from Jelle's own description of his six-week blocks under Ben Reszel, covering both Las Vegas T100 and the 70.3 World Championship builds. The signature feature is the hard/easy rhythm, escalating bike race specificity, and the deliberate focus on keeping the body fresh enough to run to full potential.
The key difference from ITU training is that the easy days are actually easy. Joel Filliol's program had Jelle at 28–30 hours of hard training every week without recovery dips. Ben Reszel's philosophy: "A couple hard weeks and then a couple of easier days, a couple hard weeks." These genuinely easy days are what allow the hard sessions to be genuinely hard — and what keeps an athlete healthy across a 10-month T100 + 70.3 season.
Jelle's Oceanside mistake is a critical coaching lesson: "In the prep towards Oceanside, everything was between 300 and 315 watts — I never saw 350 or anything in those build-ups. And actually, because of group dynamics and courses, it's a lot more spiky than you'd think." Training a flat power output for a race that is never flat sets athletes up for a shock when the race accelerates. The Friday spiked block session specifically addresses this. Always train the race dynamics, not just the average.
Jelle's shoe selection approach is worth noting as a coaching principle: he tests race shoes in the final sessions of his build on identical rep sets — comparing different options on the same 800m session. "I did those same 800s with the Vaporfly and the Ons and I felt best in the Ons." Race shoe selection based on feel in a fatigued training context is more reliable than testing them fresh. Build this into the final race-specific week for your athletes.
Jelle's Taupo race plan is one of the clearest examples of intelligent pacing strategy in recent triathlon history: "I knew I could probably run a 66 or 67 depending on how hard the bike was, so I just said — if Hayden runs 65, he deserves the win." Committing to your own pace rather than chasing is a mental skill, not a physical one. Build the race plan with your athlete before race week, and make sure it is grounded in training data — lactate values, threshold sessions, confirmed paces. Then commit to it regardless of what happens in the first 2 kilometres of the run.
Why It Works — Coaching Keynotes
Jelle's method is the clearest example of an ITU athlete successfully transitioning to middle distance by applying the right adaptations — not just copying what Ironman athletes do. These keynotes come directly from his own words and the verified data from his world championship wins.
Data Sources
All training data in this blueprint is sourced from the athlete's own public statements, verified interviews, and published race data. Nothing is inferred or fabricated.
The Triathlon Hour (2025) — Jelle Geens Interview
The primary source for this blueprint. Jelle describes training philosophy, methodology, key sessions, and race preparation in their own words. All quoted material and specific numbers in this blueprint trace directly to this interview.
Supplementary Research — Published Race & Training Data
Race results, split data, and training context cross-referenced from published race data. Used to verify the plausibility of stated training numbers and to contextualise the athlete's competitive trajectory. No training data comes solely from this source without primary-source corroboration.