At time of writing, we’re deep into Vuelta a España where the world’s finest continue to reach incredible heights, made even more impressive now the season’s eight months old, many starting at the Tour Down Under in mid-January; in fact, take into account the cyclocross season and the likes of Tom Pidock, Wout van Aert and Mathieu van der Poel are riding hard miles nearly all-year round. It’s an incredible exhibition of durability, which is a hot topic in sports science circles right now. But what exactly is durability and how do you train it? Good questions…
Under-23s versus WorldTour
James Spragg is a coach at Tudor Pro Cycling, the Swiss UCI ProTeam owned by Fabian Cancellara. Coach is also an expert on durability in cycling as that was the subject of his PhD, studied at the University of Cape Town in South Africa.
In 2020, Spragg co-authored a paper in the International Journal of Sports Physiology and Performance that looked at the durability of a rider, not over a season but over a multi-stage race. “We monitored under-23 and professional (from Continental to WorldTour) at the Tour of Alps to see what differences there were between the two cohorts over the five-day race,” Spragg explains. “We found that in terms of fresh power numbers, the groups were pretty much the same. But in terms of the numbers that they could do when fatigued, that was where the real difference lay.”
More precisely, in this study the under-23 rider’s fatigue noticeably kicked in between 1,000 to 3,000kJ of work done. It led Spragg and the team to conclude, “In their maturation toward the professional level, under-23 cyclists are recommended not only to optimise their power-to-body mass ratio and progressively improve their power profile for both short- and long-duration efforts, but also to consider improving their fatigue resistance.”
Multi-disciplined riders like Wout van Aert and Mathieu van der Poel take on almost year-round racing (Simon Wilkinson/SWPix)
Interestingly, they also noted the fatigue resistance exhibited by the GC riders. “Professional domestiques tended to display a drop in their power profile after 2,500 to 3,000kJ. Whether this was as a result of a physiological inability to sustain a given power output or a result of their ‘job’ within the team being completed for that particular day/stage is unclear. Interestingly, though, GC riders showed no decline in the power profile even after 3000kJ, suggesting that their fatigue resistance and high relative power-output values underpin their role.”
All in all, the strongest riders showed a physical stoicism that left their lesser contemporaries chasing their shadows as a race rolled on. But how? What magical training formula did the most durable riders show over their fatiguing rivals? “Further research is recommended to better understand the optimal way in which these improvements can be achieved,” concluded the journal.
Cue Spragg’s follow-up research, published in the European Journal of Sport Science in 2022, that assessed durability across the season. We’ll come back to that shortly. For now, it’s relevant to remind ourselves what fatigue is. Back to Spragg. “It’s dependent on the intensity of exercise. Typically we quantify fatigue, especially in cycling, in terms of work done, so kilojoules of work done. Sometimes we normalise that to body mass or kilojoules per kilo, just because a heavier rider going uphill at the same speed will be generating a higher power output, and therefore they’ll be burning more kilojoules per minute.
The tricky thing with professional cycling, in terms of durability, is that races take place over a spectrum of intensities. That’s from the very easy stuff through to maximal sprint efforts, and they’re all intertwined throughout a race dependent on the dynamics of that day.
“So, the things that are causing you to slow down are different when you’re going very easy compared to when you’re riding very hard,” Spragg adds. “You can think of them in terms of central mechanisms and peripheral mechanisms. But actually, there’s a lot of crossover between the two.”
Central is the proficiency of your brain to kick out signals to your muscles to contract and how well are those signals getting to, and then activating, the muscles. Peripheral is how much force does that muscle fibre produce when it’s asked to contract and how well can it maintain that level of contraction.
Where it becomes messy is when you experience a lot of peripheral fatigue, so you accumulate substances in the muscle that inhibit the way that muscle contracts and makes it less efficient and produces less force. Those substances are sensed by receptors around the muscles, which are sent back as a signal to the brain to induce a level of central fatigue. That’s where you get some crossover which complicates things somewhat. Then there’s the mental side of fatigue, like motivation to do a task. But that opens a whole new can of durable worms. For now, we’ll focus on the physiological side and Spragg’s research on durability across the season.
“One thing we did see is that after 2000kJ of work, we saw much more variation in fatigue across the season,” he says. “This tallies when riders say their form’s changing – it’s getting better or getting worse.”
Spragg then examined their riding load – both training and racing – to see if there were any trends between the riders who held form late into the season and the ones that started to suffer; in other words, the ones who possessed greater durability. “The riders that maintained durability did it in two ways. They either increased or maintained volume, or they undertook a lot of sweetspot-style training. So they reduced the volume a little bit, but they increased average intensity.”
“However, the only riders that actually increased their durability were the athletes that increased their volume,” he continues. “And by increasing volume, they had to drop that middle zone. They had to keep a certain amount of intensity but they ended up following a more polarised plan, driven by more volume, rather than intensity.”
Durable tales from the peloton
There are two key areas to unpick here: riding volume plus the polarised aspect. Which is where Dan Martin comes in. The former professional’s palmarès is impressive and includes winning two stages of the Tour de France, one apiece at the Giro d’Italia and Vuelta a España, plus two of the five Monuments, Liège-Bastogne-Liège and Il Lombardia. It’s a breadth of success that begins in Liège in April and ends in October with Il Lombardia. Yes, it might not be in one season but does highlight consistent success nearly all-year round and, he says, was down to racking up the competitive miles.
“Every year I competed at the Vuelta, I podiumed at Il Lombardia,” he says. “Basically, the Vuelta takes over from another massive training block. If you don’t do the Vuelta or Tour of Britain, you struggle into October as it’s so hard to motivate yourself to train at that time of year.”
While Martin saw it as a psychological imperative to keep on racing, Spragg’s research saw it as a physiological one, in search of a high riding load (albeit Martin’s memory does him a disservice. When completing the Vuelta-Il Lombardia double billing, his results were: 2009 – 53rd at the Vuelta and eighth at Lombardia; 2011 – 12th at Vuelta and second at Lombardia; 2013 – DNS stage eight at Vuelta and fourth at Lombardia; 2014 – eighth at Vuelta and first at Lombardia; 2015 – DNS stage eight at the Vuelta and 52nd at Lombardia; and 2018 – DNS stage 10 at Vuelta and ninth at Lombardia. A still impressive record).
Arguably, this maintenance, even increase, of riding load to forge durability as the season ticks by is more about training than racing in the modern peloton. As of writing (end of stage 11 of Vuelta) and with few 2023 race days remaining, Remco Evenepoel had raced 55 days (8,397km) and Jonas Vingegaard 57 days (8,766km). Even old hands like Luke Durbridge had ‘only’ racked up 63 days (9397km). That contrasts to times gone by. As a snapshot, in 2011 to 2013, Martin raced for 12,557km (81 days), 11,671km (71 days) and 12,273km (78 days), respectively.
Dan Martin was well versed in performing well into October (Cor Vos/SWPix)
“These days, the top riders spend far more time on altitude camps and preparation than actual racing,” Martin observes. “This focus is leading to sensational performances. On the flipside, I do worry about the longevity of their careers. All the pressure of being monitored, of being away for so many days, that could curtail a rider’s career. Still, you can’t argue that the evolution of sport science is resulting in stunning results across a long season.”
Benefits of polarised training
Delving into the physiological and psychological pressures of racing is for another time. For now and our focus on durability, let’s look at the polarised factor identified by Spragg. Polarised training, or 80/20 training as it’s often known, is a formalising of research undertaken by one of the world’s foremost exercise physiologists, Dr Stephen Seiler of the University of Agder, Norway.
Seiler’s research revealed that elite athletes trained around 80% of the time at ‘low intensity’ and 20% hard. call low-intensity. But when we say ‘low’, we mean pretty easy; when we say ‘hard’, we mean very hard. Seiler’s endurance epiphany happened around 10 years ago with his paper, ‘Intervals, Thresholds and Slow Distance: The Role of Intensity and Endurance Training.’ Within, Seiler analysed a huge swathe of previous studies into training intensity and duration where the American concluded that 80/20 is the optimum split to produce peak endurance performance.
Why isn’t fully understood but there’s evidence that low-intensity riding is the real fatigue buster. Studies have shown that during prolonged running at low intensity, the muscles release large amounts of a cell-signalling compound called interleukin-6 (IL-6), which contributes to fatigue. Well-trained runners produce less IL-6, and this is one reason they are more fatigue resistant.
The theory goes that exposure to large amounts of IL-6 during endurance exercise is the primary trigger of physiological adaptations that reduce IL-6 during future efforts and elevate endurance, with the primary trigger identified as glycogen depletion. Long, slow rides cause much higher levels of glycogen depletion – and subsequently IL-6 release – than short, fast runs. A hard ride lasting an hour may increase IL-6 levels twofold. A three-hour ride will increase them tenfold.
Ultimately, the body can also cope with high levels of low training, slowly adapting along the way, whereas too many high-intensity sessions are so stressful they suppress the parasympathetic system and result in chronic fatigue.
Specificity of training
Of course, it’s a little reductionist to split the intensities as one session hard, one session easy. It’s become common for elite cyclists to undertake a mix of intensities in one ride to more accurately replicate that of a race. It’s all about precision for optimum performance. Which is why the likes of Spragg use kilojoules as a key workload metric in both their studies and coaching, especially when it comes to measuring fatigue and durability. “That’s not new, though,” Spragg says. “Coaches and riders have been using that for a few years now.”
Yes they have. Back to Martin. “Earlier in my career, you’d separate long endurance rides and shorter, harder sessions. But I recognised early on that you really need to practise hard efforts at the end of a five-hour ride to match the race demands. That’s why pretty early on, I’d replicate the kilojoule count of a race in training.
“When I won Liège, in training I’d go pretty hard for four hours and then do two hours moto-pacing and sprints at the end. I’d even start off like I was riding in the neutral zone. I remember when I won Liege [in 2013], that was the first time I concentrated on getting that kilojoule count up and being able to do those two three minute explosive efforts at the end of a 5000kj ride. That made me more durable in the race and I suspect over the season.”
Nutrition is a vital part in remaining durable (Pauline Ballet/SWPix)
Nutrition plays its durable part, too, as there’s evidence that carbohydrate oxidation rates go up as the season progresses while fat oxidation rates go down. This, says sport scientist Jens Voet, is a strong argument to focus on carbohydrate intake throughout the season, especially during rides. Voet’s also studied durability in cycling and, he tells us, increasing how much you can consume during rides could help prolong peak performance, not solely on the day but throughout the season.
Martin agrees. “When I started, we’d consume around 60g carbs an hour in training. Now, they’re looking at 100-120g. This is where being away on camps for so long is advantageous. At a camp, you’ll have a team car follow you and hand you nutrition all the time. At home, heading out for a five-hour ride with 600g carbs is impractical so you don’t always hit the optimum amounts.”
So, where are we? Polarised training looks likely to boost durability. As does maintaining, if not increasing, rider load throughout the year. Using kilojoules as a training metric is a useful gauge of how durable, or not, a rider is, while elevating carbohydrate intake as the race months pass by could stave off fatigue. A little anyway. In short, from Australia to Lombardy, it’s a helluva long and brutal season where only the toughest thrive.
Cover photo by Zac Williams/SWPix