The Science of Running

By Alex Hutchinson Cadence and Injury; Beyond Carb-Loading; Why Do Men Crash; Cramp Cure

You don’t usually find marathoners browsing in the protein powder aisles of the health-food store. To cover long distances efficiently, you want maximum fuel (generally carbohydrate, though some argue for fat) and minimum bulk. Protein helps build muscle, but big biceps just weigh you down.

At least, that’s the conventional wisdom. But University of Toronto researcher Daniel Moore, working with colleagues f rom the Japanese company Ajimoto Co., suggests that runners may require more protein than previously thought. That’s partly because protein doesn’t just build new muscle; it also helps rebuild and repair the minor damage and wear-and-tear caused by regular training. In addition, it supplies five to 10 per cent of the energy burned during long runs, and may have more subtle effects like speeding up post-run rehydration and refuelling and strengthening your immune system.

Previous studies tracked nitrogen in the body to estimate that endurance athletes needed 1.2 to 1. 4 grams of protein per kilogram of body weight each day. Moore and his colleagues used a newer, more accurate technique called “indicator amino acid oxidation” to measure protein use. After a threeday protocol in which experienced runners ran 10k, 5k and then 20k, the results showed that they consumed an average of 1.65 g/kg/day; to be safe, the researchers recommended that runners aim for about 1.8 g/kg/day.

Of course, most Canadians get far more protein than the recommended daily allowance of 0.8 g/kg/day for sedentary adults anyway. And runners who train a lot tend to eat more of everything, meaning they get more protein too. The more important challenge is timing. To trigger muscle growth and repair, the body can typically only use 20 to 30 grams at a time, so four to six modest doses of protein throughout the day – a cup of cottage cheese, for example – is better than getting most of your daily protein from a massive hunk of meat at dinner.