Common Mistakes Athletes Make When Training for an Ironman Triathlon (And How Coaches plan to Avoid Them)

Training for an Ironman is one of the most demanding yet rewarding challenges in endurance sports. With 140.6 miles of swimming, cycling, and running ahead of you, the preparation phase is crucial—not just to finish but to perform at your best. However, many athletes make common mistakes that can derail progress, lead to injury, or prevent them from reaching their full potential.

At PGC1-Coaching, our science-backed, world-class triathlon coaching helps athletes of all levels—beginners to elite—avoid these pitfalls. Whether you're searching for online triathlon coaching or in-person support, here’s what you need to watch out for when preparing for an Ironman.

1. Training Too Much, Too Soon

Many athletes, eager to prepare for the immense challenge of an Ironman, ramp up their training too quickly. They jump straight into high mileage and intense sessions without building the necessary aerobic foundation. This often leads to overtraining, fatigue, and injury.

How PGC1 Helps:

We emphasise progressive overload, ensuring you build endurance gradually while allowing proper recovery. Our triathlon coaching programs are designed to optimise volume and intensity at the right stages to prevent burnout.

Triathlon Coach Rhianne Hughes in an Aero Tuck on her way to securing her professional athlete status.

2. Neglecting Strength and Mobility Work

Swimming, cycling, and running put significant stress on the body. Without strength and mobility training, weaknesses can develop, leading to poor biomechanics and increased injury risk.

How PGC1 Helps:

Our coaching integrates structured strength training to improve resilience and efficiency. We also focus on mobility work to ensure you maintain optimal movement patterns throughout training and on race day. Our strength plans are integrated into your training via the TrainingPeaks app and developed by Head of Strength Coaching Molly Butterworth.

3. Not Fuelling Properly for Training and on Ironman TriathlonRace Day

A common mistake in Ironman training is underestimating the importance of nutrition. Poor fuelling can lead to energy depletion, digestive distress, and race-day bonking. All of which have a negative impact on your training performance and ultimately race day performance too.

How PGC1 Helps:

We provide individualised nutrition strategies tailored to your needs, ensuring you train and race with optimal energy availability. Our approach considers carbohydrate periodisation, hydration, and race-day fuelling to help you sustain performance across all three disciplines.

Coach Jack holds a Masters in Physiology from Loughborough University including distinction in Sport and Exercise Nutrition modules.

4. Ignoring Ironman Race-Specific Preparation

Many athletes train hard but fail to simulate race conditions. Training in the wrong terrain, ignoring brick sessions, or not practicing open-water swimming can lead to a shock on race day.

How PGC1 Helps:

Our Ironman triathlon coaching plans incorporate race-specific workouts, including open-water sessions, race-pace efforts, and transition practice. We ensure you're fully prepared for the demands of your chosen race course.

5. Not Prioritising Recovery

Endurance athletes often believe that more training equals better results. But without adequate recovery, fitness gains are limited, and injury risk skyrockets.

How PGC1 Helps:

We integrate structured rest days, recovery sessions, and monitoring tools to ensure your training load is balanced. Our coaches use data-driven insights via the TrainingPeaks coaching tools to adjust plans based on fatigue levels, so you stay healthy and progress consistently.

PGC1 Athlete Gary Bennett leaving the swim

6. Lack of a Structured Ironman Plan

One of the biggest mistakes is training without a clear, structured plan. Many self-coached athletes follow generic schedules or train based on feel, leading to plateaus, inconsistency, or improper periodisation.

How PGC1 Helps:

Our online triathlon coaching provides you with a personalised training plan, written on a weekly basis, built around your goals, strengths, and weaknesses. We ensure your Ironman preparation is methodical, data-driven, manageable around life and optimised for peak performance on race day.

7. Not Working with a Coach

Even experienced triathletes can benefit from expert guidance. A triathlon coach can provide accountability, structure, and objective feedback, helping you train smarter and avoid costly mistakes.

How PGC1 Helps:

With PGC1-Coaching, you gain access to experienced Ironman coaches. Rhianne Hughes is a professional long course athlete herself and Jack Bond has a PhD in Human Exercise Physiology alongside working with long course athletes.  Rhianne and Jack work closely with you to refine your training, optimise recovery, and maximise race-day success. Whether you’re new to Ironman or aiming for a PB, our coaching is designed to help you succeed.

Training and racing is fun on a PGC1 plan!

Ready to Train Smarter for Your Ironman?

Avoiding these common training mistakes can be the difference between a frustrating race and a personal best performance. If you're serious about Ironman success, consider working with PGC1-Coaching, where we provide science-backed, online triathlon coaching to help you achieve your endurance goals.

📩 Contact us today to learn how we can help you structure your training and achieve your best Ironman performance!

You can book in for a free consultation with our Founder Joshua Schofield using the link here: https://www.pgc1coaching.com/booking-calendar/free-triathlon-coaching-consultation?referral=service_list_widget