Beyond carb-loading
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. P rotein
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 from 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.
P revious 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 three-
day protocol in which experienced runners ran
10 k, 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 every-
thing, 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.S
ome runners look very smooth;
others (and I’m one) look
awkward. But it turns out to be surpris-
ingly difficult to look at a runner and
predict how likely they are to get
injured. One of the most promising
candidates for a simple warning sign
is running cadence, which is the
number of steps you take in a minute.
Those with low cadences – relative
long, slow steps, in the 160s or lower –
are thought to be more likely to crash
down heavily on their heels, raising
their risk of injury.
A recent study from researchers
at Harvard ’s Spaulding National
Running Center put this theory to the
test, comparing 32 healthy runners
with 93 injured runners. The injured
runners actually had a slightly ( but not
significantly) higher average cadence of
164 , compared to 161 in the uninjured
group. More importantly, there was
no correlation between cadence and
average or instantaneous vertical load
rate, two measures of how hard your
foot hits the ground. Having a slow
cadence, in other words, didn’t seem
to increase the pounding your joints
absorb.
That doesn’t necessarily mean
cadence is irrelevant. Other studies
have found that increasing your
cadence by as little as five per cent
may reduce the load on your knees
and hips, while increasing the load on
your ankles – so it may be helpful for
some but counterproductive for others.
Cadence also increases when you run
faster, making it difficult to propose
universal “ ideal ” cadence targets. The
bottom line: just as you can’t judge
a book by its cover, you can’t judge a
runner by cadence alone.Cadence and Injury
26 Canadian Running November & December 2016, Volume 9, Issue 7
Thescienceofrunning
alex hutchinson rounds up the latest in endurance research