How Well Can Your Quads Handle a Beatdown?

Whether you’ll finish strong – or not – in your next marathon depends on the answer.

At the 2012 Madrid Marathon, Spanish researchers recruited 40 runners to undergo a battery of tests immediately before the race and again within three minutes of finishing. The goal was to understand why so many runners fade in the final kilometres of long events. When the results were tabulated, none of the usual suspects – dehydration, high core temperature, low blood sugar, and so on – could explain which runners faded the most. Instead, the best predictor was muscle damage.

With each stride, your quadriceps and calf muscles undergo “eccentric” contractions: momentum forces the muscles to lengthen, even as you try to shorten them to push off again. This produces a steady accumulation of microscopic damage to the muscle fibres. It’s well known that this damage causes the infamous next-day soreness after a marathon, but the Spanish study showed that it can also hobble you during the race. Runners whose pace dropped by more than 15 per cent from the beginning to the end of the race had levels of creatine kinase and myoglobin – both by-products of muscle damage that can be measured in blood tests – that were 53 and 112 per cent higher, respectively, than those who maintained a steadier pace.

It’s tempting to assume that the faders simply didn’t train as much as the maintainers. But age, experience, and training were not able to explain the differences, according to Juan Del Coso, the study’s lead author. In research published earlier this year, Del Coso and his colleagues showed that genes play a role in how susceptible you are to muscle damage. Still, he says, there are some countermeasures that can help battle-proof your leg muscles before a long race.


Among the many benefits of a regular long run is that it generates the kind of damage you want to avoid in the race itself. Thanks to a phenomenon called the “repeated bout effect”, triggering muscle damage even once leaves those muscles less susceptible to damage the next time. The catch? Del Coso believes you need to include at least one long run that’s relatively close to marathon pace – and a half marathon isn’t long enough. Schedule a 30K run at close to marathon pace about four weeks before a marathon, or else do an extended warm up before a half marathon (or an extended cool down after, if the logistics are easier).


Another way to build up your ability to tolerate eccentric muscle damage is with resistance training. Do lower-body strength exercises such as squats and weighted lunges twice a week during your training cycle, cutting back to once a week during your taper. For maximum damage protection, Del Coso suggests including weights of at least 80 per cent of the heaviest load you can lift – but be sure that you’ve mastered the correct form and movements before you attempt anything this heavy.


If you’re preparing for a long trail race, you’ll face the double whammy of distance and downhills, which amplify the damaging effects of eccentric contractions. Levels of creatine kinase after the 164K Ultra-Trail du Mont-Blanc race, for example, averaged more than 13,000 units per litre, compared with just 564 in the “high damage” group at the Madrid Marathon. In addition to resistance training, make sure to run plenty of downhills (on a treadmill if necessary), simulating the gradient, distance, and pace of the race. Experiment with your stride to find ways of descending as lightly as possible, perhaps by increasing your cadence.


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