Unlike a triathlon, there’s no swim leg, which makes duathlon a great option for strong runners and cyclists who either dislike swimming or struggle to fit it into their training. However, that doesn’t mean it’s an easier alternative.

The demands on your legs are higher, as there’s no upper-body-driven discipline to break up the fatigue. Managing energy levels across both runs and the bike segment is key to avoiding burnout in the final leg.

Pacing is another major difference. The first run in a duathlon is often deceptively fast, as adrenaline kicks in and competitors push harder than they should.

Learning to hold back slightly in the opening run so that you can maintain power on the bike and still have enough left for the final push is crucial for success.

Another key difference is pacing. In a triathlon, the swim acts as a warm-up of sorts before the main effort. In duathlon, you hit the ground running—literally—so pacing the first run is crucial to avoid burning out before the bike leg.

Key differences at a glance:

• Fatigue management: Triathlon allows some recovery during the swim; duathlon is entirely leg-driven.
• Pacing strategy: In duathlon, the first run can make or break your race if you go too hard too soon.
• Training focus: Duathletes need to master running on tired legs, as the second run can be brutal.

• Strength Training: Focusing on leg endurance, core stability, and injury prevention will give you an edge. Squats, lunges, and plyometric drills can improve power output.
• Cadence Work: Since cycling cadence impacts your running legs, practicing different pedal stroke speeds will help make the transition smoother. Aim for 85–100 rpm on the bike to keep your legs fresh for the run.
• Running Drills: Interval training, tempo runs, and hill sprints help build endurance and speed. Given the fatigue from the bike leg, running on tired legs should be a core part of training.

If you’re already comfortable with running or cycling and want a fresh challenge, a duathlon is a brilliant test of endurance and strategy.

The mix of disciplines, the variety of race formats, and the tactical pacing required make it an exciting event to train for.

Many experienced triathletes use duathlons as off-season races to maintain fitness, while cyclists often enter to improve their running. For runners looking to add variety, the bike segment provides an excellent way to build endurance without the impact of additional running mileage.

If you enjoy pushing yourself and want to experience a new type of race, duathlon could be exactly what you’re looking for.

Castle Race Series hosts a variety of duathlons, making it easy to find an event that matches your skill level and goals.

How do I pace myself in a duathlon? Pacing is key. Start steady on the first run, build intensity on the bike, and leave enough in the tank for the final push.

Do I need a special bike for a duathlon? Not necessarily. A road bike is ideal for most races, but if you’re competing in an off-road duathlon, a mountain bike or gravel bike is a must.

What should I eat before a duathlon? A carb-rich meal a few hours before the race helps maintain energy levels. Avoid heavy, slow-digesting foods.

Is duathlon harder than triathlon? It depends on your strengths. If swimming is a weak point, duathlon might feel more manageable. However, duathlons demand strong pacing since both disciplines heavily tax the legs.