I know I’m not the only running geek who whiles away the odd half-hour poring over race time predictor charts and online calculators to get a glimpse of my potential. Plugging in your 10km time and finding that you are on course for a sub-3.15 marathon provides an impetus to keep training diligently. But there are no cast-iron guarantees. As Greg McMillan, creator of one of the most widely used pace calculators points out, every runner is unique. “Over time, you learn how best to interpret and modify the predicted race times and optimal training paces to fit your particular strengths and weaknesses, as well as your goals,” he says. I generally use a range of recent performances – say, 5km through to half marathon – rather than a single result to gauge a potential finish time, but Asics Running Lab’s new Running Ability Measurement goes one better, offering a fully personalised prediction. The assessment looks at everything from cardiorespiratory fitness to flexibility and strength, limb alignment, body composition and running form before estimating your marathon and half-marathon potential.
“Prediction charts have a place, but there are so many other factors that must be taken into consideration,” says Lydia Meddings, manager of the Running Lab. “If you simply increase mileage and pace to reach the goal predicted by a 10-mile or 10km time without ensuring you have the appropriate strength, alignment and running form to support it, injury risk could be high.”
I am impressed with the specificity of the tests involved. That old chestnut, the sit-and-reach test – a poor, but oft-used assessment of hamstring flexibility – is absent, but mobility at the hips and ankles – crucial to good running form – is measured in every direction. And when it comes to strength, an isokinetic dynamometer calculates how much strength you can exert against a lever moving at a constant speed – this provides a better picture of how strength changes at different joint angles.
In the gait analysis, I am filmed front, back and side and the results collected are both qualitative (“arm swing is different between your right and left arms. The left elbow is away from the body”) and quantitative (step frequency ranges from 180-190 steps per minute). The final part of the test is the aerobic fitness measurement. Usually, this entails a VO2 max test (VO2 max is your capacity to deliver and utilise oxygen in the muscles). But this particular test measures a different variable – anaerobic threshold – by monitoring respiratory metabolism during a submaximal, but progressive, test. “Anaerobic threshold (AT) is the point at which you begin to use carbohydrate as your main fuel source,” explains Lydia Meddings, running services manager. “This is the data point that is used to estimate your marathon time.”
The verdict? I am capable of running a marathon in 3 hours and 34 minutes. Given that my last three 26.2 outings have all been within a few seconds of 3 hours 22 minutes, I’m somewhat disappointed. Perhaps I’m not as fit as I was on my last marathon outing – though according to my trusty prediction chart my recent 10k still translates to a 3 hours 20 minute marathon. Which raises the question, what is the test measuring – my ability to run 26.2 miles tomorrow or my genetic potential? Neither, says Meddings. “This is by no means the sum total of all you are capable of in terms of PBs over marathon distance – it is based on your current anaerobic threshold, with the premise that you stick to the training guidance given to gradually increase the time you can spend at the pace associated with it.”
Training vs genes
So one thing that prediction tools and this test have in common is the presumption that if you do the training, you’ll get the results. But increasingly, research suggests that when it comes to how our bodies respond to exercise, some of us are more equal than others. This was first demonstrated in 1995 by the landmark Heritage Family Study, a project designed to evaluate the role of genetic and non-genetic factors in cardiovascular, metabolic and hormonal responses to aerobic exercise. In one of the studies, 742 completely sedentary people were put on a progressively challenging 20-week training programme, and their physiological responses measured. VO2 max improved by an average of 17% – but while some participants improved by as much as 40%, others didn’t improve at all. The team labelled these unfortunates “non-responders”.
It’s depressing to think that all those miles in the bank could amount to nothing. A newly available multi-gene DNA test now claims to find out just how good a responder you are – the XRPredict+ test involves filling in a lengthy questionnaire and sending off a saliva sample from which your DNA profile is analysed. “The analysis involves scoring a set of DNA sequences for the occurrence of specific nucleotides – the building blocks of DNA,” explains Professor Jamie Timmons, from XRGenomics, a company founded by the scientists behind the original research . “In each case, you either have a nucleotide profile that is favourably associated with improvements in aerobic capacity with exercise training, or not. The combination of these scores is used to determine how likely you are to make gains in aerobic capacity following an exercise training programme.”
I was quietly confident I’d turn out to be a high responder, so it was another blow to my athletic ego when my results finally arrived and I’d been classified as a medium-low responder, with a score of 45%. But what does this actually mean, in terms of how worthwhile my training is, and what I might be capable of achieving? Are my dreams of a sub-3.15 marathon in tatters? “It means that you won’t demonstrate a 40% gain in aerobic fitness with an intense training programme, as a high responder could,” says Timmons. “You have the potential to increase your aerobic capacity in response to a programme of endurance training by about 15%.”
So if your capacity to respond to exercise isn’t in your own hands, you might question the point of having the XRPredict+ test at all. Timmons demurs: “Knowing whether you are a low or high responder allows you to focus on realistic goals” In the case of a non responder, the test can help explain why an aerobic training regime is not yielding the expected results – with advice on what steps you can take to improve your health and fitness. For example, says Timmons, focusing on resistance training.
So while I was initially disappointed to find that I could only improve my aerobic capacity by 15% – I thought of those athletes at the top of their fields, for whom even a 1% improvement could make the difference between winning and losing. So I’ll be adding some high-intensity interval training to my weekly regime and keeping that marathon PB in my sights. After all, my prediction chart says it’s possible.
• The Running Ability Measurement costs £200. The XRPredict + test costs £199,
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