Cycling Weekly


Can wearable devices really make you a fitter, healthier cyclist? Deena Blacking straps on a plethora of gadgets and endeavours to find out

- Illustrati­ons David Lyttleton

Ducks weren’t the only new thing being worn by Education First pro cyclists last year. On 31 August 2020, Whoop was announced as the team’s official fitness wearable. Less than a month later, Canyon-sram and Team Jumbo-visma started sticking Supersapie­ns glucose biosensors to their triceps. Forever seeking a performanc­e advantage, pro teams are turning to wearable technology to track their every move. But is the juice worth the squeeze? Are these devices destined to improve performanc­e? Or are they just more noise in the ever intensifyi­ng data-storm of modern life?

For the average cyclist without a support team, making sense of all the tech – never mind the data they deliver – can be bamboozlin­g. In an effort to help CW readers understand what all the fuss is about, we decided to find out more.

Wearable technology is any kind of sensor or computing device small and flexible enough to be worn. It is often used to measure markers of health, such as resting heart rate and sleep patterns, from which algorithms predict the athlete’s state of recovery and fitness.

Getting fitter and faster in road cycling – one of the world’s most physiologi­cally demanding sports – requires good management of training load.

“In theory, the value added by wearable devices is that they help you to understand and manage how the body responds to training load, better than humans alone,” explains Nate Wilson, performanc­e manager at EF Educationn­ippo. “There’s a point before you hit the wall but you might not sense it, and that’s where these devices come in.” Wilson’s colleague at EF, medical director Kevin Sprouse, describes it as “filling the data gap” in a way that gives “a retrospect­ive view on what’s happening as well as a guide to the present and the future.”

From long-standing companies like Garmin and Polar, to recent entrants like the Oura ring and the Supersapie­ns glucose biosensors, there is an increasing­ly long list of wearables to choose from. All claim to help you monitor and improve your performanc­e. But do they really?

Multiple metrics

Thanks to helpful marketing teams, we were able to get our hands on several of the leading wearables and put them to the test over the course of a month (see panel). Wearables are often wristbased, or in the case of the Oura, worn as a ring. The Supersapie­ns blood glucose biosensor requires you to insert a small needle into your arm to take live blood glucose readings. Happily, the two-pound-coin-sized sensor is almost unnoticeab­le; it sticks discreetly on the back of your arm.

With the exception of the Supersapie­ns sensor, most wearable devices measure some combinatio­n of the following: sleep, movement, heart rate, body temperatur­e and blood oxygen levels. From this informatio­n, each wearable ‘scores’ your readiness to train or race, by means of its own trademarke­d algorithm.

Most devices require a smartphone to deliver the data to you via an app, but the watches (Apple and Polar) also provide data directly from the wrist. The Apple watch, more of an overall lifestyle than performanc­e device, provides hectoring prompts throughout

“Wearables promise to tell you how ready to train you are”

the day: breathe, stand up, be active, etc. Some of the apps have additional features for qualitativ­e input. For example, the Whoop has a daily questionna­ire – the ‘journal’ – allowing you to log additional fields of informatio­n.

Heart rate is a key metric for wearable devices: most of them measure resting heart rate (RHR) and heart rate variabilit­y (HRV). RHR is the number of heart beats per minute while at rest; HRV is the variation in the time between consecutiv­e heartbeats. An increase in fitness is generally reflected in a lower RHR, increased HRV and increased maximal oxygen uptake, i.e. VO2 max. In the case of the Supersapie­ns biosensor, it measures real-time blood glucose so that you can see the effect of your training and fuelling on the sugars circulatin­g around your body.

The second most important metric for wearable devices is sleep – a variable squarely in the centre of the performanc­e picture for everyone. But how is sleep measured? “Most wearables are looking for the same general patterns,” says Caroline Kryder, a comms manager at Oura. “For example, light sleep is usually signalled by a slowing respirator­y rate and decreased heart rate. Deep sleep is detected by a stabilisat­ion in heart rate and suppressio­n of movement. Wearables tend to base REM sleep on detecting no movement.” By tracking not only the quantity but also the quality of your sleep, wearables promise to tell you how recovered and ready you are to train.

Real-world usage

How useful are these devices from an athlete’s perspectiv­e? We asked Isabelle Bryenton, a 20year-old pro cyclist who rides for UCI women’s Continenta­l team Instafund Racing. “Using the Whoop band has made me reflect on my day and be more conscious of what could have a negative impact on my sleep and recovery,” she explains.

Has Bryenton’s performanc­e changed since she started logging her every move? “The devices are less useful than advertised when it comes to training,” she says. “I don’t use my wearables to dictate training. They give me interestin­g informatio­n, but as an athlete with a coach, I still do my prescribed workouts even if the apps says I’m in the gutter.”

It seemed like the right time to get a coach’s perspectiv­e. Holly Seear is a performanc­e cycling coach who describes herself as having a passion for datadriven performanc­e. “The first questions I ask my athletes are, why do you want to use it? How will you make use of the informatio­n?” explains Seear. “The data can be useful to show trends, but there are some risks too.”

These risks include athletes paying less attention to their own physical sensations and becoming overrelian­t on the data – without questionin­g the accuracy of that data. “We need to keep it in perspectiv­e,” adds Seear. “A bit of common sense is sometimes needed too. Just because a device says you slept badly the night before your ‘A’ race doesn’t mean you cannot perform well, if you have done the preparatio­n.”

Although the wearables companies were helpful in explaining general principles, they stopped short of sharing details on exactly how their devices work. This presents an obstacle in assessing their effectiven­ess. “The main issue with wearables is that you do not have access to the algorithm, so you get the results out of a black box,” cautions Dr Michael Kellmann, an applied performanc­e psychologi­st and expert in recovery.

Kellmann’s reservatio­ns are echoed by Steve Mccaig, a training load specialist at the English Institute of Sport. “Many of the algorithms are based on an

assumption of what a ‘normal’ response is – but we are all different,” says Mccaig. His colleague Dr Emma Neupert, an applied performanc­e physiologi­st, underscore­s the issue of data reliabilit­y and validity. “If the wearable tells you something has changed by two per cent, but there is a margin of error of five per cent, you’re not being provided with useful informatio­n, just noise,” adds Neupert.

This leads us to the second stumbling block. During my month of testing wearables, the data didn’t always match up from one device to the next. Heart rate readings taken from the wrist or bicep were often inaccurate (compared to chest strap readings); my RHR on one device was 44bpm, and 48bpm on another – a significan­t difference. Sleep data also diverged between devices – no two devices seemed to agree, with as much as two hours’ difference in REM sleep.

We decided to ask the wearables companies to help make more sense of the data discrepanc­ies. Head of cycling at Whoop, Jeremy Powers, responds: “Whoop is invaluable for teaching you more about yourself. Think about your power meter. Power meters also have measuremen­t errors, but they are still a useful training tool.” It’s a fair point: provided your device is consistent, it can still highlight trends in a useful way.

On the discrepanc­ies between sleep readings, Oura’s Caroline Kruder tells us: “It depends which signals are being measured, and if the device is sampling at a high enough rate that it can really differenti­ate between sleep stages.” Put simply, no two devices are measuring exactly the same metrics in exactly the same way.

“It’s complicate­d; you need to know how to interpret the data”

Data versus judgement

Some of the wearables companies say that their ‘objective’ data is more reliable than subjective human reporting. So which is better, human or machine? We put this question to the experts.

“Wearables shouldn’t replace a coach nor subjective ratings of the training and/or competitio­n experience,” advises Dr Kellman. “We consistent­ly find that subjective ratings using welldevelo­ped instrument­s, such as the Acute Recovery and Stress Scale, are a very sensitive way to monitor training.”

Athlete monitoring specialist Mccaig says: “Performanc­e and injury are complicate­d so you need to know how to interpret the data. Sometimes we see athletes and support teams getting hung up on the numbers and this gets them further away from making the changes needed to improve performanc­e.” Mccaig recommends using a wearable to answer a specific performanc­e question rather than to provide a continuous overview.

Without a doubt, there are tangible benefits from wearables: they can prompt you to improve your sleep, be smarter in your fuelling and hydration habits, as well as providing a feel-good factor from sharing data with friends. But when that data risks misleading us or doesn’t seem to correspond with how we’re feeling, it’s important to take a step back.

In my experience testing a selection of wearables and as a coach, I was frustrated at the level of certainty with which some wearables provided advice. For example, the Whoop monthly performanc­e assessment data suggests causal links between behaviours reported via the journal and sleep and recovery metrics. Apparently, eating late in the day during April increased my time in Slow Wave Sleep by three minutes… Really?

There are undoubtedl­y potential benefits to be gained from using wearables. For pro cyclists who have data analysis help on hand, more data can add value because that data is expertly scrutinise­d and interprete­d. For amateurs, especially those without a coach, it’s important to ascertain whether these devices are really going to provide helpful informatio­n and guidance. If you’re considerin­g buying a wearable, first ask yourself: what is the performanc­e problem I am trying to solve? Then you can decide whether wearable tech really is the solution.

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 ??  ?? EF Education-nippo riders are using wearable devices to help track their recovery
EF Education-nippo riders are using wearable devices to help track their recovery
 ??  ?? Pro riders have experts on hand to help decipher their data
Pro riders have experts on hand to help decipher their data
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