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Core Training in Triathlon: Myths, Misunderstandings, and Can It Help Performance?

The research on the benefits of core work for triathletes is sparse and confusing.

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“Core training” has long been a well-known and commonly used training tool in triathlon. Despite this, most triathletes and coaches end up using it in a less than optimal manner, simply due to an overwhelming lack of clarity on what core training actually is and how it’s best used.

Here I’ll aim to create clarity on these questions, so you (as a triathlete) can improve how you use core work and core strengthening. The goal is to translate core work to greater performance gains and the prevention of common triathlon injuries. 

Is there evidence for core training?

Surprisingly, despite the widely accepted benefits and the use of core training in triathlon, the actual evidence from scientific research looking at its influence on performance and injury is very limited. To my knowledge, no triathlon-specific studies have been conducted and only a handful have been done in the disciplines of swimming, biking, and running. Research in trained adults has reported core strength training improves run performance, running economy (i.e. the amount of oxygen you use each minute while exercising), and sprint cycling speed—in comparison to not including core training. 

Yet other studies have found no improvements from core training, including in cycling performance. The lack of clear research on the effectiveness of core training raises questions around the popularization of “doing core,” and if myths are likely to exist on the topic.

The irony is that when comparing core strength training to traditional strength training, the latter has been questioned more and used significantly less by triathletes and coaches. Yet the actual scientific evidence on the benefit of traditional strength training for improving speed, power, endurance, and reducing injury risk is both compelling and conclusive—in comparison to core training. 

How your core works as a triathlete

The muscles that support your spine are commonly referred to as your “core muscles.” These act to stabilize your spine, which both optimizes the transfer of force through your body and helps create movement, such as that of rotating and pulling your body through the water when swimming. They also work to protect your spine against the forces placed upon it, including those you encounter during ground contact when you run. 

The unique demands your body experiences as a triathlete, particularly due to performing three different disciplines, means you can’t necessarily extrapolate from the research looking at the general population and the use of core strength training on such things as generalized lower back pain. Despite this, one of the most common rationales for core strength training in triathlon is based on research linking the lack of activation in deep core muscles (e.g. transverse abdominis) to back pain in the general population. But that’s not the same as how you use your core when swimming, biking, or running.

How should you train your core for triathlon?

Another problem is that because research has shown that when you move you don’t actually maximally contract your core muscles, this has popularized the belief that you don’t need to strength train in this way. This is despite decades of broader research on strength training clearly showing that optimally improving any strength is best achieved when contracting muscles maximally. For example, despite the fact that when you run your gluteal and quadricep muscles don’t maximally contract, research now shows that to improve distance running performance via strength training you clearly should use maximal contraction. 

Therefore I recommend using the same, well-researched principles of strength training, when doing core strength training, including: 

  • Using sufficient intensity (multiple repetitions using loading approx. 75-85% of your one-rep max) 
  • Not using excess volume/reps (e.g. avoid long plank holds of beyond a minute) 
  • Using sufficient rest periods relative to the work between sets of core exercises

While many core strength exercises—such as sit-ups, crunches, twists, and the many variations—are movements that promote moving through your spine, there is a strong and logical belief that core strength training is actually best executed using isometric contractions with your core muscles. This is partially based on the observation that during running, biking, and swimming there is very little movement in the lumbar spine. Therefore the muscles of the core, which stabilize the spine during these, have little change in their length—a term called an “isometric” contraction. The principles of strength training suggest that you should train muscles specifically to the way they contract when you perform. Consequently, logic suggests you should instead focus on core exercises that limit movement in your lumbar spine while enabling you to contract your core muscles isometrically. Examples being: 

Core strength training, when performed in line with the demands of triathlon and principles of strength training, are a beneficial tool—despite limited research. It improves your performance by increasing your power and reducing your energy expenditure at a given speed, via better transfer of forces through your body as a result of stability created by the muscles supporting your spine. However, a number of long-standing myths and misinterpretations currently limit many triathletes from using core strength training in a way to truly deliver these benefits most effectively. The suggestions here form the basis of how we use core strength training in the triathletes we coach of all ages and abilities.

Dave Cripps holds a Master’s degree in sport science and is an accredited strength and conditioning coach in the U.K. He’s currently the Director of TriTenacious, a leading online strength and conditioning resource for triathletes, and Coalition Performance, one of the U.K.’s most successful private physical fitness training facilities.