At the 2016 Science and Triathlon Conference, held at the National Institute of Sport and Physical Education in France, French sports scientist Romauld Lepers spoke about how mental fatigue affects performance.
He focused heavily on professor Samuele Marcora’s psychobiological model of fatigue. “Marcora says that we stop or slow down when we have either exerted the maximum effort we are willing to exert for success – in other words, lack of motivation limits us – or we believe we have exerted our maximal possible effort – in other words, our perception of effort limits us,” explained Lepers. This conflicts with the classic physiological model of fatigue that says you begin to work back through the gears when either lactic acid rises or you run out of glycogen (energy).
Fatigue your mind
There are many strands to Marcora’s model and Lepers stressed that there’s no getting away from hard work – if you’re not strong enough, your mind perceives the greater activation of muscle fibres to project yourself forward as potentially dangerous and so you’ll slow down. However, the psychobiological model suggests that, as long as you’ve done the physical part, mentally taxing tasks alter how hard or easy you perceive a physical activity, in triathlon’s case how hard a swim, bike or run session is. That has potential performance connotations, as we’ll discover…
The Kent University lecturer had subjects undertake a 90min computer-based cognitive task known as the AX-CP test, followed by cycling to exhaustion at 80% maximum power output. Marcora discovered that endurance time decreased by 12% after the participants had been mentally fatigued.
But that doesn’t mean you should refrain from triathlon training if you’re mentally tired. Instead, Leper showed that you should train at least once a week after work when you’re fatigued. This, according to Marcora, has a similar effect to high-gear work in cycling or paddles in swimming – namely, though more debilitating at the time, once you remove that extra resistance (in this case, mental fatigue), you’ll race stronger and longer.
Talk yourself faster
Lepers also illustrated how motivational self-talk can reduce mental fatigue and have you exercising longer, citing the work of Anthony Blanchfield and his team at Bangor University. “Similar to Marcora, Blanchfield had subjects cycle to exhaustion at 80% maximum power output twice punctuated by two weeks of motivational self-talk intervention,” Lepers said. “Phrases included ‘drive forward’ and ‘you’re doing well’. The authors showed that time to exhaustion increased by 17% while rate of perceived exertion (RPE) felt easier.”
Time for a cuppa
And if fatiguing your mind or self-talk fail to stimulate greater physical performance, it’s time to hit the legal psychoactive drugs. Lepers presented the work of Doherty and Smith, whose meta-analysis concluded that consuming 4-7mg/kg of caffeine before training not only lowered perception of effort by 6%, but also increased exercise performance by 11%. The researchers also discovered that over 75% of elite athletes consume caffeine before and during competition.
As performance nutritionist at British Athletics Sophie Killer told us when we’d landed back in the UK from Paris, “Caffeine is so effective as an ergogenic because you have receptors all over the body, even in the brain, which caffeine latches onto. Caffeine’s one of these rare substances that can cross the blood barrier. It acts centrally on the central nervous system and dampens the messages that are sent to the brain saying you’re getting tired. Essentially it lowers the perception of effort. In the muscle it’s a completely different response. Caffeine clings onto adenosine receptors, which increases muscle-firing capacity, so you’re able to generate higher forces. Caffeine also improves reaction times and aerobic capacity.”
Over the years, sports scientists and exercise physiologists have examined the impact of training physiological parameters like aerobic capacity, lactate threshold and power output. From 2016 onwards, it looks like the brain will become an ever-increasing focus of your training programme…
5 takeaway tips for beating fatigue
1 Perform at least one training session each week after work. You’ll be mentally fatigued, which will make the effort feel harder but it’ll pay off come the races. There’s also evidence that you’ll benefit more from a short, high-intensity effort rather than long and slow.
2 Conversely, before competition, avoid cognitive tasks that cause mental fatigue. Simple methods to decrease the mind drain include preparing your kit and nutrition the night before the race; leaving for race registration in plenty of time; and carefully laying out your gear in transition. All these methods reduce anxiety and stave off mental fatigue.
3 Practise self-talk in training to see how it impacts your performance. It doesn’t matter whether you internalise the self-talk or verbalise, but keep it positive. Rather than, ‘This is hard, I’m struggling’, say, ‘I’m pushing through this to beat my personal best. Keep arms pumping and the legs will follow.’ It sounds twee but it’s proven to work by all levels of athlete.
4 Caffeine is the most exhaustively proven legal ergogenic on the market. Recent research has shown the positive results are similar whether you ingest in pill form (ProPlus) or by beverage. And contrary to popular opinion, habitual caffeine users benefit as much as non-habitual users.
Caffeine: what, when and how much to take
5 Marcora’s also working on a brain-training app with a U.S. company called Axon Sports. Watch this space…
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