This month marked three years since I started
writing articles for RunnersConnect.net investigating what the scientific
literature has to say about a wide range of running-related topics, from injuries
to training to peak performance on race day. At the end of each year, I've made a list of one useful tip or interesting fact that I learned from each week's research. Here are fifty-two more things I learned from reading scientific
research this past year, one from each article.
If you want to see all of the material I've written, head on over to
the blog section of RunnersConnect! Also feel free to check out the yearly lists from 2013 and from 2012.
1. Celiac
disease, which affects around one percent of the population, can cause a wide
range of vague, non-specific symptoms that can interfere with your training,
like joint pain, extreme fatigue, weight loss, gastrointestinal problems, and
anemia. Further, even once you've
adopted a gluten-free diet, it can take a while for your body to return to
normal.
2. If you
choose to eat a vegetarian or vegan diet, you're more likely to have
iron-deficiency anemia, amenorrhea (if you are a woman), and insufficiently
vitamin B12 levels. Though
it's very possible to have a complete diet as a vegetarian or vegan, you need
to take extra care to ensure you get enough protein, vitamin D, and iron, and
you should probably take a vitamin B12 supplement or eat foods that
are fortified with it.
3. Scientific
findings can run contrary to your own experiences. The research says it's okay to run when you
have a cold, that the speed of your daily runs does not affect your injury
risk, and that it's okay to do some running on an injured area, as long as you
monitor your pain and stop before it's over 5/10 on the pain scale. In my own training, I can't get away with any
of this! There might be subtle reasons why the findings from one study don't
apply to your own experiences.
4. The
faster you run, the greater the proportion of your energy that comes from
carbohydrates. This has some major
implications when it comes to running out of fuel in the marathon. The people most at-risk for "hitting the
wall" before the finish of a marathon are very fit runners who can run at
a high percentage of their VO2 max, and heavier, overweight runners—especially
if their extra weight is not in their legs.
5. When
planning out a fueling strategy for a marathon, you should generally shoot for
taking in 60 grams of carbs per hour of running. If you have had major problems with hitting
the wall, you may consider increasing your carb intake to 90 grams per
hour. However, if you've had
gastrointestinal problems from trying to refuel, you might want to cut this
down to 45 or 30 grams per hour.
6. Gels,
sports drinks, and energy chews are all equally valid choices for refueling
during a long race. None of them offer a
distinct physiological advantage, so feel free to choose whichever suits you
best.
7.
Electrolytes aren't all that important for endurance events. There's no good evidence that you need to
replace the salt you lose in your sweat—it appears that your body intentionally
modulates the amount of salt you lose in your sweat to keep the concentration
of electrolytes in your blood constant, so there's no need for salt tablets or
super-salty sports drinks.
8. There's
no magic formula for carbo-loading. All
you need to do is increase your carbohydrate intake by 50-75% over the last few
days leading up to a long race (over 90 minutes), and you don't need to do a
"depletion period" prior to it to get the benefits of carbo-loading.
9. In a
marathon, elite Canadian runners consume between 16 and 26 fluid ounces of
liquids per hour of running and about 50-75 grams of carbs per hour. Elites use a combination of gels, solids, and
sports drinks according to personal preferences.
10. When
runners collapse after finishing a
race, it's usually (though not always) from a sudden drop in blood pressure
that's triggered when you stop running.
After laying down for a few minutes and elevating their legs, they'll be
fine. When runners collapse during a race, however, it's much more
likely that they're having a medical emergency like hyponatremia or sudden
cardiac arrest.
11. Some
research suggests that taking vitamin C before and after completing an
ultramarathon can decrease your risk of getting sick. Over half of the finishers of a 90km ultramarathon
in one study came down with a cold in the weeks following the race!
12.
However, try not to load up on antioxidant supplements in general. They can inhibit your body's adaptation to
exercise: oxidative stress is a big part of improvement! Fruits and vegetables
are probably okay, though.
13. In the
ultramarathon, the ideal age for top performances seems to be between your
mid-30s and early 40s. This is a
distinctly older age range than is typical for top performers in shorter
events, like the 5k, 10k, or even the marathon.
14. Ultramarathoners
generally tend to get the same types of injuries as regular runners, though
they appear to get fewer stress fractures in general, though when they do get a stress fracture, it's far more
likely to be in the metatarsals than would be typical for a road runner.
15. Initial
findings of a large-scale study of ultramarathons appear to show that
long-distance running confers some significant general health benefits. Ultra runners averaging >40 miles per week
spend less time in medical care and have lower rates of virtually all serious
medical conditions when compared to the general public. Hay fever and asthma are more common among
ultra runners, though.
16. Rotating
between two different pairs of shoes for your daily run might prevent injuries,
though it's too soon to tell for sure—the only study which supports this was a
retrospective study, not a randomized controlled trial.
17.
Surprisingly, there isn't any evidence that consuming electrolytes
during a workout leads to a performance benefit compared to just plain
water. The benefits of sports drinks in
long events appear to be entirely because of their carb content.
18. Knowing
your VO2 max is great if you're a running nerd, but by itself, it
isn't a very helpful number. A more
relevant parameter is your vVO2
max, or how fast you run when you are at your VO2 max. This can be determined by physiological
testing, but is also pretty easy to predict from your 5k PR.
19. Your
risk of heat illness is much higher for short, continuous all-out races like a
5k or a 10k race. Counter-intuitively,
running longer competitions like a marathon carries a significantly lower risk
of heat illness.
20. Beetroot
juice appears to boost performance by about 1% in sedentary or
recreationally-active athletes, but does not have any effect in well-trained
runners.
21. For
running in hot weather, you don't need to worry about weighing yourself before
and after your run to determine water losses.
Just drink to thirst, and understand that it is perfectly normal and
healthy to lose a few pounds of water weight when you run. It is, in fact, dangerous to replace 100% of your weight losses by drinking water
during your run.
22.
Cramping during exercise is not associated with heat or electrolyte
levels. The best weapons against muscle
cramps are stretching and a solid warm-up routine with some dynamic exercises.
23. Taking
a swig of pickle juice immediately after a muscle cramp occurs is a very
effective way to shorten the duration of a painful cramp, but it has nothing to
do with electrolytes. Instead, it
appears to work by sending a "reset" signal to your central nervous
system, which stops the neuromuscular "glitch" causing the cramp.
24. Though
there's been only a few studies on the topic, wearing sunscreen doesn't appear
to negatively affect your ability to stay cool in the heat, so don't hesitate
to put some on for a long run in the summer.
25. In hot and humid weather, women have a slight
edge when it comes to heat management because they sweat more efficiently and
tend to be smaller in size. Men,
however, have a small advantage in extremely hot, very dry weather.
26. Even if
you can't make it to Flagstaff for eight weeks of altitude training, you can
still take advantage of the "training camp effect" by taking
advantage of lower stress levels, better sleep, and an improved diet that tends
to happen when you take a break or vacation.
27. If you
control for relative exercise intensities (as a percentage of VO2
max), children and teenagers aren't any more susceptible to overheating during
exercise in hot conditions than adults.
28. You'll
start to see the negative effects of high altitude on running performance at
about 3,000-4,000 feet above sea level.
If you're traveling to a location above 8,000 feet, you should take a
few rest days to acclimate before you work your way into running.
29. You
should not do a hard, continuous workout or a race within the first week of
recovering from an illness that included a fever—you run the risk of heat
stroke, even in cool conditions.
30. It
takes about three weeks for your performance to return to normal after donating
blood. Donating plasma only affects your
performance for a few days. Donating
blood too often can lead to
chronically low ferritin levels.
31.
"Altitude masks" which use resistance-breathing mechanisms to
try to simulate training or living at altitude aren't worth it—they don't train
the same biological pathways as real altitude, and there isn't a body of
high-quality research that supports their use.
32. Despite
how often you hear about tracking your resting heart rate (even from me...), it
is not a reliable indicator of overtraining, and there's no good research on
heart rate response when you're sick either.
33. A typical GPS watch is accurate to 1% of true distance
on a flat, straight path with a clear view of the sky. In an urban environment, GPS watches are
accurate to 3%, and in a heavily-forested area, 6%.
34. Foam
rolling is a fairly reliable way to reduce muscle soreness after a
workout. For increased efficacy, use a
hard-cored roller instead of a pure foam one (or build your own using 3"
PVC pipe)
35. Successful
studies on foam rolling prescribe at least two sets of 60 seconds of foam
rolling per muscle group—a far more intense rolling session than a typical
runner casually lounging around on the foam roller tends to do. Additionally, they prescribe short,
kneading-like motions for each roll, starting at the "bottom" of a
muscle group and gradually kneading back and forth up to the
"top." Once you've reached the
top, roll back down in one smooth motion and start again.
36. Icing
is of questionable use for overuse injuries.
Strangely, there isn't a single study that's even investigated ice as a
rehab method for an overuse injury.
However, if icing is useful,
the best way to go about it is to apply ice for 10min, then take a 10min rest,
then reapply for another ten minutes. Research
on ankle sprains found better results from broken-up icing sessions like this
compared to a single 20min icing session.
37. Taking
a sauna on a regular basis might boost your blood volume, allowing for up to a
2% performance boost in a race.
38. Race
conversion charts can be designed to measure one of two things: predicted
performance over one race distance based on another, or the relative competitiveness of one performance compared to
another. It's important to recognize the
difference!
39. If
you're a "marathon maniac" who does multiple marathons in only a few
weeks' time, or an ultramarathon who does multi-day events, proper fueling is
essential. If you don't sustain your
energy requirements in your diet during a block of extreme running, your body
will start consuming its own muscles and fat reserves.
40. Running
with your head tilted back or too far forward can make the same pace feel
harder—generally, you should keep your head and neck relaxed when you run. But if you're kicking it in at the end of a
race, don't worry if you have to throw your head back or tuck your chin down to
squeeze out an extra ounce of energy, since it won't have a measurable impact
on your real running economy.
41. If
you're running a multi-stage relay event like the Ragnar Relay, fuel up with
carbs and protein after each
leg. Shoot for a carb to protein ratio
of 3:1 to 5:1. This should help top up
your carbohydrate reserves as fast as possible.
42. The
faster you run, the greater the percentage of your forward motion is generated
by your hip extensor muscles become in generating power. Building glute strength by doing squats,
lunges, bounding exercises, and uphill running should improve your ability to
run at high speeds.
43. Stride
frequency is not usually a limiting factor when it comes to how fast you can
run. When running at top speed, even a
two-year-old has the same stride frequency of a 20-year-old! The reason why
adults can run so much faster than children is because they can generate more
power each step.
44. Poor
hip flexion and extension range of motion might increase your injury risk. Doing hip mobility exercises like stretching,
the lunge matrix, and hurdle drills can help address this.
45. In female
athletes, poor hip extensor strength and especially an imbalance side-to-side
is connected with low back pain. The
biomechanical reasons behind this are not clear, but this connection has been
identified in fairly large, well-designed studies.
46. One of
the main reasons runners slow down significantly in old age is because their
muscles aren't capable of generating enough power to switch to the
"asymmetric" stride pattern that's necessary for optimal efficiency at
speeds faster than 8:45 per mile. To
stave off age-related losses in muscle mass and muscular power, older runners
should hit the weight room and focus on the major muscles of the legs.
47. Hip
strength programs for rehabbing injuries take an average of three to six weeks
to have an effect. If you're doing a hip
strength program for a running injury, be patient! It takes time to increase
your hip strength.
48. Though
heavier runners are at a performance disadvantage, there isn't any relationship
between your weight and your injury risk.
If anything, runners who are too
light—especially women—are at a greater risk of injury.
49. After a
low-risk stress fracture or stress reaction, you can begin to transition back
into running with a graduated, pain-monitoring program as soon as you've been
pain-free while walking normally (i.e. without a boot or crutches) around and
going about your daily activities for several days.
50. Because
of how low your carbohydrate usage is while at rest, an overnight fast only
burns off three or four miles' worth of carbs (150-200 Calories, depending on
speed). Fortunately, it's pretty easy to
make up this deficit with a granola bar or a banana and a piece of toast.
51. Though
research is limited, there's nothing to suggest that taking short breaks for a
stoplight or to use the bathroom has a negative impact on the benefits of
training. However, if there is a benefit to keeping your heart rate
elevated, stopping even for a minute will result in a significant drop in heart
rate in a well-conditioned runner.
52. In one
study, the benefits of 150 minutes of weekly training were the same, regardless
of whether the training was split into five 30min sessions or two 75min
sessions on consecutive days!
I hope you've picked up a tip or two from the
research I've done in the past year on such a broad range of topics. Here's to another year of weekly writings!
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