Each week in my Research Update, I distill the latest sports science research into three practical insights to help you improve your training, performance, and recovery.
In this week's update:
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A 12-week tracked HYROX athletes weekly to measure the prevalence, burden, and risk markers of health problems and injuries during training and competition.
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A randomized trial examined whether creatine monohydrate supplementation, with or without an accompanying exercise and diet program, affects body composition, cognitive function, and health markers in sedentary middle-aged and older adults.
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A review pulled together 70 studies on why runners fade during the marathon leg of Ironman-distance triathlons, and found a surprisingly basic question nobody has actually answered yet.
HYROX Athletes Are Getting Hurt More Than the Hype Lets On, and It's Almost All From Overuse
This study followed 89 HYROX athletes (33 men and 56 women) for 12 weeks, having them fill out a standardized weekly health-problem questionnaire (the OSTRC-H2) alongside training logs, to get a real picture of how often athletes get hurt and what actually breaks down.
In any given week, 30% of athletes reported some kind of health problem, and 18% reported one serious enough to affect their training or performance. Over the study, injuries occurred at a rate of 14.4 per 1,000 hours of exposure, with about two-thirds of those directly tied to HYROX training itself rather than other activity.
The standout finding is that 73% of injuries were overuse injuries rather than acute ones, and the knee was the single most frequently and heavily affected area, followed by the lower leg. Shoulder injuries, despite all the wall balls and sled work, were almost nonexistent. Having a previous injury was the strongest predictor of a worse outcome this time around, though the confidence interval on that finding was wide enough that it's suggestive rather than certain.
Why it matters:
HYROX's whole pitch is that it's for "every body," and its running-plus-functional-fitness format doesn't look as brutal on paper as something like CrossFit's barbell cycling. This is one of the first studies to actually track a cohort of HYROX athletes prospectively rather than just asking them to recall injuries after the fact, and it suggests the real risk isn't a dramatic single-rep injury, it's the knee and lower leg slowly breaking down under repeated running and station volume, the same overuse pattern you'd worry about in a marathon training block.
My thoughts:
I like that this study didn't just ask athletes to remember what hurt months later; weekly check-ins over 12 weeks catch the nagging stuff that usually gets waved off until it's a real problem. The overuse-versus-acute split is the headline for me: if you're ramping up HYROX volume, your knees and lower legs are probably the first place to watch, and "previous injury" being the biggest risk marker is a good reminder that an old niggle you've been training through deserves more respect than it's getting. Worth pairing with sensible load management rather than just sending it every session.
Creatine Might Do More for Your Brain Than Your Biceps as You Get Older
This study put 73 sedentary middle-aged and older adults (64 completed the trial) through 12 weeks of either a placebo or 10g of daily creatine monohydrate, with half of each group also following a structured exercise and diet program.
Across the board, creatine supplementation—even in the group that didn't change their exercise or diet habits—was associated with better maintenance of lean muscle mass and strength, along with favourable shifts in blood lipids and, notably, cognitive function markers. The exercise-plus-diet groups saw the biggest overall improvements, but creatine's benefits showed up on top of that, not just alongside it, and the supplement was well tolerated throughout.
Why it matters:
Most of the creatine conversation is about power output and lifting numbers, but this is part of a growing body of evidence that creatine's benefits extend to brain health and healthy aging, not just the gym. For masters athletes and anyone thinking about creatine as a long-term habit rather than a training-cycle supplement, this is a reason to keep taking it even during a lower-training-volume stretch of life.
My thoughts:
This is the kind of study that reframes how I think about who creatine is "for." It's easy to file it under lifting, sprinting and repeated efforts, but the fact that a sedentary older adult who didn't change anything else still saw favourable shifts in cognitive markers is a pretty compelling reason to treat creatine as a fundamental healthy-aging supplement, not just a performance one. If you've got parents or older training partners who think creatine is "just for gym bros," this is worth sending their way.
Nobody Has Actually Measured Why Your Marathon Falls Apart at the End of an Ironman
This scoping review pulled together 70 studies to map out everything we know and don't know about why running performance declines during the marathon leg of an Ironman-distance triathlon.
The review confirms that pacing patterns and performance predictors during the run leg are reasonably well studied at this point, but the mechanistic side (what's actually happening physiologically to cause the fade) relies almost entirely on short, tightly controlled lab protocols rather than real racing conditions.
The authors point out a genuinely surprising gap—no study has yet directly quantified the difference between an athlete's standalone marathon time and their actual marathon-leg time in an Ironman, using real race data, to put a number on exactly how much the swim and bike cost your run.
Why it matters:
If you've ever done a triathlon and been shocked at how much slower your "Ironman marathon" was compared to your open marathon PR, this review is basically confirming that the sports science world hasn't rigorously quantified that gap either, and it's mostly been assumed or estimated informally. For anyone building an Ironman training plan around a goal run split, that's a useful dose of humility: the models predicting your run time off your open marathon fitness are working with less hard data than you'd expect.
My thoughts:
I actually find this kind of review more useful than a flashy new finding. It's an honest map of what we don't know, from people who read 70 papers to get there. The lack of real race-data research on the "marathon time versus Ironman run time" gap stood out to me because it's such an obvious, practical question. Until someone does that study, I'd treat your Ironman run goal as a rough estimate rather than a guarantee, and lean on your own race history over any generic formula.
— That's all for now, train hard!
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