How to Taper for an Ironman Triathlon

Joshua Gordon, PhD

Tapering for an Ironman involves reducing training volume while maintaining intensity and frequency to ensure peak race-day performance. A well-structured taper prevents accumulated fatigue without losing fitness. Here are the key takeaways:

• Don’t fear loss of fitness: A well-designed taper enhances glycogen stores and maintains neuromuscular sharpness.
• Ideal taper length: 8–14 days works for most, but it varies based on individual needs.
• Swim taper: Reduce volume but keep frequency and intensity to maintain feel.
• Bike taper: Retain more volume with short bursts of intensity.
• Run taper: Reduce volume significantly while keeping race-pace efforts.
• Kamikaze Taper: Some athletes perform well with a short, intense effort 6–8 days before race day.
• Experimentation is key: Adjust and refine your taper based on past race outcomes.

Introduction

Hi, I’m Joshua Gordon—a PhD statistician and endurance athlete with 11 Ironman finishes, 3 Ironman World Championship finishes, and 2 Half Ironman (70.3) World Championship finishes, with a personal best Ironman time of 8h52. Over the years, I’ve experimented with different tapering strategies, made mistakes, and fine-tuned what works.

Let’s talk about tapering. At its core, tapering is about reducing training load in the final weeks leading up to a race to optimize performance. It’s a balancing act: cut too much, and you might feel flat; cut too little, and you toe the start line carrying too much fatigue. Tapering isn’t just about training less—it’s about adjusting volume, intensity, and frequency in a way that keeps you sharp while allowing your body to fully absorb months of training.

Most sports use tapering in some form, but when it comes to ultra-endurance events like Ironman, the approach has to be different. You’re not just managing fatigue from one sport—you’re balancing swimming, cycling, and running, each with its own recovery timeline and tapering needs. In this post, I’ll break down how tapering works, what the research says, and how to find the best approach for your Ironman performance.

Research Review

Common Misconceptions: Fear of Losing Fitness During a Taper

One of the biggest mental battles during a taper is the fear of losing fitness. Many endurance athletes feel sluggish or worry that their performance will decline because they aren’t training as much. However, while detraining is real, it doesn’t happen overnight, and there are ways to mitigate it while still allowing for proper recovery.

Why a Proper Taper Doesn’t Cause Detraining

Detraining happens when you stop training completely for an extended period. A proper taper, however, does not eliminate training—it strategically reduces volume while maintaining intensity. This approach ensures that:

• Blood volume remains high, keeping cardiovascular efficiency intact (Coyle et al., 1986).
• Neuromuscular sharpness is maintained through short, high-intensity efforts (Shepley et al., 1992).
• Glycogen stores are replenished, helping sustain race-day energy levels (Bosquet et al., 2007).
• Oxidative enzyme activity and glycogen synthase levels stay high enough to prevent major metabolic declines (Coyle et al., 1984).

Research supports that a well-structured taper can increase muscle glycogen concentration and enhance performance on race day.

(Images from Coyle et al., 1986)

How to Find the Right Taper Length

Finding the right taper length isn’t a one-size-fits-all approach. While research suggests an 8–14 day taper works well for many endurance athletes (Bosquet et al., 2007), individual variability plays a huge role. Factors like training volume, intensity, prior fatigue, and personal recovery speed all affect how an athlete should taper.

(Images from Bosquet et al., 2007)

A theoretical study by Thomas & Busso (2005) used mathematical modeling to analyze optimal tapering strategies, concluding that taper effectiveness depends on previous training volume and intensity.

Nuances Between Swim, Bike, Run, and the Full Ironman Taper

Tapering for triathlon is more complex than tapering for a single discipline, as it requires balancing recovery and performance optimization across swimming, cycling, and running—each with different physiological demands.

• Swimming: Requires the longest taper, often up to two weeks or more, while maintaining frequency and intensity to preserve neuromuscular coordination (Mujika, 2011).
• Cycling: Allows for relatively high volume retention, as it is non-impact and less physiologically taxing compared to running. Maintaining intensity is key (Aubry et al., 2014).
• Running: Requires the most significant volume reduction—often 50% or more—to mitigate impact stress while preserving race readiness (Banister et al., 1999).
• Triathlon-Specific Considerations: Managing cumulative fatigue across all three disciplines is critical. Exponential tapers (gradual reductions) tend to yield the best results over step-reduction tapers (Jakob et al., 2023).

A Standard Triathlon Taper 

Below is a typical Ironman taper plan based on traditional methods:

Why This Doesn’t Work for Me

I’ll be honest—this traditional taper doesn’t work well for me.

The biggest issue? Volume drops too much. As mentioned earlier, research suggests that optimal tapering involves a volume reduction of 21–60% over the final 8–14 days. My personal sweet spot is at the lower end of that spectrum—I only drop about 21% of volume, and only for 8 days.

So, based on both research and my own experience, I’ve realized I’m not an anomaly—I just respond better to a shorter, less drastic taper.

My Adjusted Taper: A Higher-Volume, Higher-Intensity Approach

Here’s what my taper usually looks like instead:

My Adjusted Taper Plan (Duration and Frequency)

Why This Works Better for Me

• Higher race-week volume keeps me feeling sharp rather than sluggish.
• I don’t reduce volume too much, too soon, avoiding that “flat” feeling on race day. Intensity is somewhat maintained, ensuring I’m race-ready rather than just “rested.”
• And at times, I’ve taken this even further... introducing what I call the Kamikaze Taper.

The Kamikaze Taper: Why Racing Right Before Your A-Race Can Work

I’ve experimented with a more aggressive taper strategy—what I call the Kamikaze Taper—that has produced strong results in both triathlon and running for me. This approach involves racing a hard, shorter event 6–8 days before an A-priority race, followed by a focused recovery period leading into the main event.

This strategy has worked well for me in multiple high-stakes scenarios:

• Challenge Roth 2023: I raced a 70.3 just seven days before and still performed well in my full-distance race.
• Ironman Kona 2024: I competed in T100 Vegas just six days prior, pushing my body hard before shifting into full recovery mode for Kona.
• Challenge Roth 2025: I’m planning to race Walchsee half 7 days prior

This method isn’t unique to me. Norwegian triathlon stars Kristian Blummenfelt and Gustav Iden have taken this concept to an extreme, completing a full Ironman within a week of their target race as part of their taper. Their training, publicly shared on Strava, shows that keeping volume high but adjusting recovery time can yield excellent results. While my approach isn’t as extreme, it follows the same principle—pushing a big and hard day about a week out to stimulate fitness gains while minimizing the risk of de-training.

Why the Kamikaze Taper Works

High-Intensity Stimulus Without Prolonged Fatigue

• Traditional tapers aim to reduce fatigue, but too much volume reduction can lead to feeling flat or sluggish on race day.
• A high-intensity, race-level effort one week before the A-race serves as a final sharpening session, engaging the physiological systems required for peak performance.
• It also helps lock in race-day pacing by simulating the demands of competition.

 

Maintaining Fitness Without Detraining

• One of the biggest concerns with tapering is losing fitness from reduced training load.
• A big race effort a week prior allows volume and intensity to drop sharply afterward, ensuring full recovery while minimizing the risk of de-training.
• Instead of a long, gradual taper, this method creates a dual-peak effect, where the athlete is still sharp from the pre-race effort but well-rested for the A-priority race.

Who Should Try This?

This tapering method is not for everyone. It works best for highly trained athletes who recover quickly, have a solid aerobic base, and are accustomed to racing frequently. If an athlete struggles with lingering fatigue or has a history of injuries, a more traditional taper may be a better choice.

For those considering it, individual experimentation is key. If you find that extended tapers leave you feeling stale, incorporating a hard but controlled race effort 6–8 days out could provide the perfect blend of fitness maintenance and recovery.

Experimenting with Your Taper Strategy

Tapering is highly individual, and the best way to refine your approach is through structured experimentation:

1. Track Past Races & Training Blocks: Analyze previous race performances and training loads leading up to events.
2. Experiment with Different Tapering Strategies: Adjust taper length, volume reductions, and intensity maintenance to see what works best.
3. Evaluate Race Outcomes Objectively: Compare perceived effort with heart rate, power, and pace data.

Sources

• Aubry, A., Hausswirth, C., Louis, J., Coutts, A. J., & LE Meur, Y. (2014). Functional overreaching: The key to peak performance during the taper? Medicine & Science in Sports & Exercise, 46(9), 1769-1777.
• Banister, E. W., Carter, J. B., & Zarkadas, P. C. (1999). Training theory and taper: Validation in triathlon athletes. European Journal of Applied Physiology and Occupational Physiology, 79(2), 182-191.
• Bosquet, L., Montpetit, J., Arvisais, D., & Mujika, I. (2007). Effects of tapering on performance: A meta-analysis. Medicine & Science in Sports & Exercise, 39(8), 1358-1365.
• Coyle, E. F., Coggan, A. R., Hemmert, M. K., & Ivy, J. L. (1986). Muscle glycogen utilization during prolonged strenuous exercise when fed carbohydrate. Journal of Applied Physiology, 60(1), 95-99.
• Coyle, E. F., Coggan, A. R., Hemmert, M. K., Lowe, R. C., & Walters, T. J. (1984). Substrate usage during prolonged exercise following a preexercise meal. Journal of Applied Physiology, 57(6), 1857-1864.
• Jakob, E. R., Hutchinson, J. C., Smith, D., & Sotir, S. (2023). The effect of Ironman taper on mood and engagement of nonprofessional triathletes: An interrupted time series study. Journal for Advancing Sport Psychology in Research, 3(2), 19-32.
• Mujika, I. (2011). Tapering for triathlon competition. Journal of Human Sport and Exercise, 6(2), 264-270.
• Rose, B. E. (2019). Tapering for triathlon: Current concepts, effects, and applications. Graduate Student Theses, Dissertations, & Professional Papers. 11423.
• Shepley, B., MacDougall, J. D., Cipriano, N., Sutton, J. R., Tarnopolsky, M. A., & Coates, G. (1992). Physiological effects of tapering in highly trained athletes. Journal of Applied Physiology, 72(2), 706-711.
• Thomas, L., & Busso, T. (2005). A theoretical study of taper characteristics to optimize performance. Medicine & Science in Sports & Exercise, 37(9), 1615–1621.
• Zarkadas, P. C., Carter, J. B., & Banister, E. W. (1995). Tapering in triathlon. Medicine & Science in Sports & Exercise, 27(5), S80.