A 1.9-kilometer swim, a 90-kilometer bike ride, a 21.1-kilometer run – the IRONMAN 70.3, also known as the middle distance or half-Ironman, is the dream of many ambitious triathletes. The 70.3 stands for the total distance in miles – and for a challenge that demands to be taken seriously.

The leap from the Olympic distance to the middle distance is significant. It's not simply 'a little more' – it's a qualitatively different experience. The demands on endurance, nutrition, mental strength, and time management increase considerably. At the same time, the 70.3 is for many the entry point into the world of long-distance triathlons – achievable with a moderate time commitment, but challenging enough to be a real achievement.

What makes the 70.3 special?

The race duration for amateur triathletes typically ranges between 5 and 7 hours. This is long enough to mercilessly expose any flaws in training and race strategy. At the same time, it's short enough that you can still maintain a reasonable intensity – unlike the full Ironman distance, which is almost exclusively ridden at a base pace.

The 70.3 is also popular because it's achievable with 10-15 hours of training per week – challenging, but compatible with work and family life. This guide will show you the way to your first half-Ironman.

Before you start training, you should understand what each sub-discipline requires of you.

1.9 km swim

Almost double the Olympic distance. For most, that's 30-50 minutes in the water. Swimming technique becomes even more critical – inefficient swimming will exhaust you for the long hours afterward. Open water experience is essential: navigation, mass starts, and waves.

90 km cycling

This is where the 70.3 is won or lost. The bike leg lasts 2.5-4 hours (depending on fitness level and course profile). Aerodynamics is crucial – small improvements can lead to significant time gains. Pacing is critical: go too fast, and the half marathon becomes an ordeal. Nutrition on the bike determines success or failure.

21.1 km run (half marathon)

After 3-5 hours of pre-race exertion, you're running a half marathon – with correspondingly tired legs. Your 70.3 half-marathon pace will be significantly slower than your fresh half-marathon pace (typically 30-60 seconds per kilometer slower). Mental strength is crucial here. The last 5-10 km are a battle with yourself.

Total time

Professionals: under 4 hours. Fast age-groupers: 4:30-5:30 hours. Solid amateur triathletes: 5:30-6:30 hours. Beginners: 6:30-8 hours (cut-off usually at 8:30). Your goal for your first 70.3: Finish and enjoy it.

Requirements

Ideal: Experience with Olympic distance triathlons. Regular training in all three disciplines. You can swim 2 km, cycle 100 km, and run 15+ km. Willingness to dedicate 10-15 hours to training per week.

Swimming 1.9 kilometers in open water requires solid technique, endurance, and mental calm.

Technical basics

Over nearly 2 km in the water, every inefficiency becomes apparent. Focus on: Body position: Hips high, streamlined. Arm stroke: Efficient catch, powerful pull, relaxed recovery. Leg kick: Minimal – a two-beat kick saves your legs for cycling and running. Breathing: Bilateral breathing helps with orientation and navigating waves. Rotation: From the hips, not just the shoulders.

Training structure

Frequency: 3 times per week. Volume: 2,500-4,000m per session. Mix: Technique, intervals, endurance, open water.

Example units

Technique Session (2,500m): 400m warm-up. 4x100m technique drills. 8x100m with paddles (focus on catch). 4x50m fast. 300m cool-down. Endurance Session (3,500m): 500m warm-up. 2,500m continuous (race pace or slightly slower). 500m cool-down. Interval Session (3,000m): 400m warm-up. 3x (400m fast + 100m easy). 5x100m fast (20 sec. rest). 300m cool-down.

Open water training

Open water swimming experience is mandatory for the 70.3. Train regularly in open water (ideally once a week during the season). Practice: navigation (sighting), mass swimming, buoy turns, wetsuit handling. Longer open water sessions (2+ km) as race simulations.

Swimming goals

Realistic goals for your first 70.3: Beginners: 45-55 mins. Intermediate: 35-45 mins. Fast swimmers: under 35 mins. The swim shouldn't exhaust you – you still have 4-6 hours ahead of you.

90 kilometers on the bike – this is where the 70.3 is decided. Those who ride correctly here will run well. Those who overpace will suffer.

The challenge

90 km means 2.5-4 hours on the bike. The distance is long enough that nutrition and pacing become absolutely critical. Aerodynamics makes a big difference at this distance. Your goal: complete 90 km efficiently and with reserves for the half marathon.

Training structure

Frequency: 3 times per week. Types: Endurance (90-120 min. easy). Tempo/Threshold (60-90 min. with intervals). Long ride (2.5-4 hours on weekends). Brick workout (bike + run).

Example units

Endurance (2 hrs): Steady pace, Zone 2. Focus on nutrition and cadence. Tempo (90 mins): 20 min warm-up. 3 x 15 mins at 70.3 race pace with 5 mins easy. 15 min cool-down. Long ride (3-4 hrs): Moderate intensity. Test race nutrition. The last 30 mins at race pace.

Pacing – the key

The biggest mistake: Riding too fast. Your 70.3 km/h cycling pace needs to be sustainable – you still have a half marathon to run afterward. Rule of thumb: If you think you could go faster – don't. Power meter: Ideal for precise pacing. Target: 70-75% of your FTP (Functional Threshold Power). Heart rate: Zone 2-3, no higher. If your heart rate is too high, slow down.

aerodynamics

At 90 km, aerodynamics make a huge difference. Aero position (aero bars, triathlon bike). Body posture: flat back, head down. Tight-fitting clothing, aero helmet. Aero can save 10-20 minutes over 90 km!

Nutrition while cycling

Nutrition is crucial for 2.5-4 hour bike rides. Aim for 60-90g of carbohydrates per hour (after the first 30 minutes). Start early – don't wait until you're hungry. Combine fluids and energy (sports drinks). Solid food (bars, bananas) is fine at a moderate pace. Test everything during training!

A half marathon is no easy feat. A half marathon after almost 2 km of swimming and 90 km of cycling is a completely different challenge.

The reality

Your 70.3 half marathon will be slower than a fresh half marathon – plan for an extra 30-60 seconds per kilometer. Your legs will be fatigued, and your glycogen stores will be depleted. The first 3-5 km often feel terrible. Mental strength is at least as important as physical fitness.

Training structure

Frequency: 3 times per week. Types: Easy runs (45-60 min). Tempo runs (30-40 min at a brisk pace). Intervals (e.g., 6-8 x 1000m). Long run (1 time per week, 90-120 min). Brick runs (after cycling).

Combined training – non-negotiable

For the 70.3, regular brick training is essential. Frequency: 1-2 times per week. Variations: Standard brick: 60-90 min. cycling + 30-45 min. running. Long brick: 3+ hours cycling + 60+ min. running. Brick repetitions: 3-4 times (25 min. cycling + 15 min. running).

Example units

Easy run (60 min): Zone 2, conversational. Regeneration and base endurance. Tempo run (50 min): 10 min warm-up. 30 min at a comfortably hard pace. 10 min cool-down. Long run (100 min): Steady, moderate pace. The last 20-30 min slightly faster (simulating the end of a race). Intervals (60 min): 15 min warm-up. 6 x 1000m fast with 90 sec recovery jog. 15 min cool-down.

Pace strategy

The first 5 km: Hold back deliberately. Your legs need to adjust. Km 5-15: Find and maintain your own pace. Km 15-21: If you still have energy – use it now. Last 3 km: Give it your all. Negative splits are the goal – the second half faster than the first.

In competitions lasting 5-7 hours, nutrition becomes a science. Those who make mistakes here either don't finish – or suffer unnecessarily.

The basics

Your body can utilize approximately 60-90g of carbohydrates per hour (even more with training). For 5+ hours of exertion, you need to replenish a significant amount of energy during the competition. Hydration is equally critical – dehydration will kill your performance.

Before the competition

The days leading up to the race: Focus on carbohydrates ('carb loading'). Eat familiar foods. Drink plenty of fluids, but don't overdo it. Race morning: Eat breakfast 3-4 hours before the start. 100-150g of carbohydrates (toast, porridge, banana). Easily digestible, low in fat and fiber.

During the competition

Swimming: No nutrition. Cycling: Your nutrition window! Plan for 60-90g of carbohydrates per hour. Start after 20-30 minutes. Refuel every 15-20 minutes. Mix of: sports drink (provides fluids + energy + electrolytes), gels (quick energy), bars/bananas (longer-lasting). Drink: 500-1000ml per hour (depending on heat and sweat rate). Running: Less nutrition needed (harder to digest). Cola/gels at aid stations (fast sugar). Water/electrolytes. Target: 30-60g of carbohydrates per hour.

What could go wrong?

Too little energy: 'Bonking' – a total energy crash. Too much at once: stomach problems, nausea. New products during competition: digestive disaster. Too little fluid: dehydration, cramps, performance drop. Too much fluid: hyponatremia (dangerous!).

Develop your strategy

Test during training: What can you tolerate while cycling? What while running? Create a nutrition plan: When will you consume what? Practice the timing: Refuel every 15-20 minutes while cycling.

Equipment becomes more important as the distance increases – aerodynamics makes a real difference when cycling 90 km.

The bicycle – the most important investment

Options: Road bike with aero bars: Affordable solution, good aerodynamics. Triathlon/time trial bike: Optimal for triathlon, more expensive, less versatile. Important: The bike must fit! A professional bike fitting is the best investment. Investment priorities: Aerodynamic position (aero bars, fitting). Good wheels (deep rims). Quality tires.

To swim

Wetsuit: Mandatory for most 70.3 events. A good wetsuit provides more buoyancy, which means speed and energy savings. Investment: €200-€600. Goggles: Reliable and fog-free. Bring a backup pair!

Run

Running shoes: Well broken in, race-ready. Some use lighter shoes for the race. Race belt and bib number: For a fast T2. Cap/visor: Sun protection for the long run.

Triathlon-specific

Tri-suit: A one-piece suit for all disciplines. Quality pays off with 5+ hours of wear time. Investment: €150-400. Aero helmet: An aero helmet can save several minutes over 90 km. Nutrition setup: Bento box on the top tube for solid food. Gel/bar holders. Sufficient bottle cages.

Technology

Bike computer: With GPS, speed, time, and heart rate. Power meter: Ideal for precise pacing on the bike. GPS watch: For pace and heart rate while running.

Budget priorities

If your budget is limited: Bike fitting + aero bars. Good wetsuit. Quality tri suit. Aero helmet (used ones are often cheap). The rest is nice to have.

This plan will take you from Olympic level to a 70.3 finish. Prerequisite: You have triathlon experience and can train 8+ hours per week.

Weekly effort

Weeks 1-8: 8-10 hours. Weeks 9-16: 10-14 hours. Weeks 17-18: Peak, 12-15 hours. Weeks 19-20: Taper, 6-10 hours.

Phase 1: Foundation (Weeks 1-6)

Focus: Building volume, base endurance. Swimming: 3 times per week, 2,000-3,000m. Cycling: 3 times per week, 60-90 min + 1 long ride (2-2.5 hours). Running: 3 times per week, 40-60 min + 1 long ride (75-90 min). Brick workout: 1 time per week (60 min cycling + 20 min running). Intensity: Mostly Zone 2, occasionally Zone 3.

Phase 2: Development (Weeks 7-14)

Focus: Increase volume, specific intensity. Swimming: 3x per week, 2,500-4,000m, including intervals and open water. Cycling: 3x per week + 1x long ride (2.5-3.5 hours), including tempo rides. Running: 3x per week + 1x long ride (90-120 minutes), including tempo runs. Brick workout: 1x per week (90 minutes cycling + 45 minutes running). Intensity: Zone 2-3 dominant, regular Zone 4 work.

Phase 3: Specific (Weeks 15-18)

Focus: Race simulation, peak fitness. Swimming: Open water, race-pace intervals, 2+ km continuous swims. Cycling: 90+ km rides with race-pace segments. Running: Long runs up to 2 hours, tempo runs at target pace. Brick workout: Race simulation (80+ km bike + 15+ km run). Weeks 17-18: Peak volume, then begin tapering.

Phase 4: Taper (Weeks 19-20)

Focus: Recovery, freshness, mental preparation. Volume: 50-60% of peak volume. Intensity: Maintain the same intensity, but shorter sessions. Last week: Only easy sessions, short increases in intensity. Nutrition: Carb loading 2-3 days before the race.

Example week (Phase 2, approx. 12 hours)

Mon: Swim 3,000m. Tue: Bike 75 min (tempo) + Run 25 min (brick). Wed: Run 50 min (easy). Thu: Swim 2,500m + Bike 45 min (easy). Fri: Rest or light swim. Sat: Bike 3 hrs (endurance + nutrition testing). Sun: Run 100 min (long).

A 5-7 hour race requires a well-thought-out strategy – here is your race plan.

Before the race

Study the course: swim route, bike profile, run route. Familiarize yourself with the aid stations. Create a schedule: Rough target times for each discipline. Plan transition times. Prepare your equipment: Check and tick off everything the day before.

Swimming

Starting position: Choose according to ability. In mass starts: Start on the outside or at the back if unsure. Pacing: Swim the first 300-400m at a controlled pace. Then swim at your own pace. Orientation: Look up briefly every 8-10 strokes. Goal: Swim efficiently, don't get out of the water exhausted.

T1

No rush – you have time. Wetsuit off, helmet on, grab your bike. Take a quick breath. Goal: 3-4 minutes (less is a bonus).

Cycling

The first 15 km: Find your pace, DON'T overpace! Pacing: 70-75% FTP or Zone 2-3 heart rate. Nutrition: Start after 20-30 minutes. Refuel every 15-20 minutes. Target: 60-90g of carbs per hour. Last 10 km: Pedal a little easier, 'free up' your legs. Hydration: 500-1000ml per hour.

T2

Bike off, helmet off, running shoes on. Maybe a cap, pack a gel. Goal: 2-3 minutes.

The half marathon

Km 1-5: Consciously hold back! Your legs will feel strange – that's normal. Km 5-15: Go at your own pace and keep it constant. At aid stations: Drink, maybe have a cola/gel. Km 15-21: Now you can push harder if you still have energy. Last 5 km: Focus mentally – one step at a time. Last km: Give it your all!

Mental strategies

Divide the race into sections ('just until the next aid station'). Mantras: 'I'm prepared.' 'The others are suffering too.' Focus on the current task, not on what's to come.

You finished a 70.3 – you're officially a Half Ironman! What's next?

recreation

A 70.3 leaves its mark. 1-2 weeks: Active recovery, very easy sessions. 2-4 weeks: Slow return to structured training. Listen to your body – regeneration takes longer than after shorter distances.

Option 1: More than 70.3

The middle distance is considered by many to be the 'sweet spot' of triathlon. Challenging, but with a reasonable training commitment. Two to three races per season are possible. Focus on improving time, technique, and tactics.

Option 2: The full distance – Ironman

The next logical step: a 3.8 km swim, a 180 km bike ride, and a 42.2 km run. Almost twice as long as the 70.3 – a qualitatively different experience. Requires: 15-20+ hours of training per week. 24-30 weeks of preparation. A significant life commitment. Not for everyone – but an unforgettable experience.

Option 3: Get faster

Focus on improvement within the distance: Perfect swimming technique. Increase cycling power (structured interval training). Improve running economy. Many triathletes spend years competing in middle-distance races and continuously improve their speed.

Option 4: Specialize

Perhaps you'll discover a passion: Focus on swimming: open water races. Focus on cycling: time trials, Gran Fondos. Focus on running: marathons with the basic fitness you've built up.

The 70.3 community

The Half Ironman community is large and active. Clubs, training groups, race trips. The experience connects people – many of these friendships last a lifetime. No matter which path you choose: You've achieved something great. Enjoy it.