Saturday, January 12, 2013

52 lessons learned from a year of weekly writing

As some of you probably know, I've been writing weekly articles for Runners Connect for the past year.  Runners Connect is a great coaching and training website run by Jeff Gaudette, a DI All-American and runner for the Hansons-Brooks Distance Project.  This most recent article marked my 52nd weekly post at Runner's Connect, so I thought I'd write up a post looking back on the past year of my writing there to 1) give a big shout-out to Jeff Gaudette and all of the folks over there and 2) give a quick glimpse at what the scientific literature has to say about a vast range of topics.  For the full articles, head over to Runners Connect.  So, here are 52 useful lessons I've learned in the last year, one from each of my posts:

1.    Picking the right shoe isn't a matter of pronation control or arch support; it's chiefly a matter of what feels comfortable on your foot

2.    Increasing your stride frequency by about 10% appears to reduce loading on the hip and knee (though not the ankle)

3.    When it comes to "core strength" for runners, strength in the hips and glutes is most important for preventing injury

4.    Don't feel too bad about skimping on strength for the "traditional" core of the abdomen and back, because there's very little evidence that they matter much for preventing injury (Note: some recent reading I've been doing has discussed a connection between abdominal weakness and hamstring injuries—expect to see an injury series article on that in a few weeks)

5.    Weakness and dysfunction in a thin, wide muscle called the transverse abdominus, which runs underneath the "normal" ab muscles, may be linked to low back and groin problems.

6.     Drinking a cup of coffee (or taking a 200mg caffeine tablet) an hour before a race or workout will give you a small but notable performance boost (and you don't have to abstain from caffeine in the preceding days either!).

7.    Medical-grade compression socks—which are not the same thing as the Nike compressionwear or Oxysocks you'd find at most running stores—might boost performance by a smidge, but they seem to be better-suited for reducing soreness after a workout.

8.    Of all of the visits to the medical tent at a big-city marathon, over 20% are related to skin issues like blistering and chafing! Protect your skin with technical gear (socks, tights, etc) to keep your skin dry, petroleum jelly or another lubricant, and by wearing shoes that you've gotten used to.

9.    Once you are "over the hill," you don't slow down quite as much as you might think: Master's runners slow by about 1-2 seconds per mile per year for races from 10-15km, and 4-6 seconds per mile per year in the marathon.  Women also close the gap between male runners as they age.



10.    It takes at least two weeks to adapt to training in the heat, and even then, it's still a significant performance inhibitor.  However, it doesn't seem to be inherently dangerous to run in high temperatures, since the body's thermoregulatory systems anticipate dangerous temperatures and slow you down before you can harm yourself.

11.    Every 100g of increased shoe mass increases your oxygen consumption by 1%.  However, wearing a lightweight shoe is more oxygen-efficient than wearing no shoes at all, perhaps because running barefoot on a hard surface doesn't allow your body to take advantage of the energy rebound coming from the ground. 

12.    If you're going to do weight training, don't go halfway: hit the gym at least three times a week for high-intensity strength training in order to see the benefits of improved running economy.  This applies for athletes of all levels!

13.    If your hips "drop" out of parallel alignment during the stance phase while you run, you likely have weak hip abductor and external rotator muscles or poor muscular coordination at your hip.  There's evidence that this can lead to injury, so work to fix any hip drop in your gait through strength exercises and coordination "drilling" while you run.

14.    You can also check your hip function by looking at your own footprints.  If your feet cross over too much, you're probably adducting your hip excessively while you run.  Fix this by trying to run along a straight line painted on a soccer field or a track and keeping your feet in line along it.

15.    You should focus on generating power in your stride by driving off the ground with your hips, not by reaching forward with your quads and shin.

16.    Running on soft surfaces demands a higher leg stiffness, which appears to preferentially stress "hard" tissues like bone.  In contrast, running on a hard surface appears to put more stress on soft tissue like muscles and bones.  However, soft surfaces do have the advantage of being more uneven.

17.    Two good rules of thumb for the costs of uphill and downhill running come from Jack Daniels and John Kellogg.  Daniels says that every percent gradient of incline slows you 12-15sec/mi and every percent gradient of decline speeds you by 8sec/mi.  Kellogg says that every 10 feet of elevation change (up or down) speeds or slows you by 1.74 sec irrespective of the horizontal distance covered.

18.    When running up a hill, "stand tall" and drive your hips back and your knees up to power your way to the top.  On the way down, quicken your stride and lean slightly forward to use gravity to speed to the bottom.

19.    Don't be afraid to try a good over-the-counter orthotic like SuperFeet or Powerstep before jumping into a custom orthotic, as studies suggest that they are often comparable in actual outcome.  Do be suspicious of an uncomfortable or ill-fitting custom orthotic, as there's evidence that these can be harmful!

20.    Calf muscle strength appears to ward off injuries to the tibia like stress fractures and shin splints.  Large muscles not only absorb more shock, but encourage the tibia to become a stronger bone.

21.    Younger and inexperienced runners get injured more than older and more experienced ones, and women are at a higher risk of injury (especially to the hip and knee) than men.  Overall injuries are lower for Masters runners, but Achilles and calf injuries are more common.  In men, the Achilles and patellar tendons seem more vulnerable to injury than in women.

22.    If you are aquajogging for cross-training, wear a flotation belt to keep the mechanics of it as similar to real running as possible.  Ditching the belt will give you a harder workout, but it will be less specific to running. 

23.    Because of the lack of wind resistance and the monotony of moving without going anywhere, running on a treadmill feels harder but is physiologically easier than overground running. To offset the lack of wind resistance on a treadmill, set the incline to 1%. 

24.    Shoe cushioning follows an exponential decay curve, meaning that shoe parameters change pretty rapidly in the first 40-50 miles of wear.  While replacing shoes after 400-500 miles is a good idea, try to find a shoe that feels good after wearing it for several weeks, not just right out of the box.

25.    A headwind can stifle your running pace by a significant degree, and a tailwind only aids you about half as much as a headwind slows you down.  But on the bright side, you can cut 80% of the air resistance by drafting behind another runner!

26.    Marathoners should try to do some longer runs right away in the morning in order to improve their body's fat-burning capabilities.  "Fasted workouts" will be slower and more difficult, but they can stave off hitting the wall in a marathon by shifting the energy substrates you rely on while running.

27.    Your body doesn't produce "lactic acid" while running, and the lactate it does produce is actually useful—the real cause of fatigue is the release of protons (H+) when you use a lot of ATP at high intensities.

28.    The ideal stride is smooth, quick, efficient, and above all, relaxed.  Working to improve your stride is important, and is best done with strides, diagonals, and conscious repetitions on flat, smooth paths. 

29.    Kinesiology tapes like Kinesiotape, KT tape, and Spider tape shouldn't be seen as primary treatments for injury, but do appear to take a bit of strain off a sore or injured area.  Interestingly, it appears to have less to do with the mechanics of the tape and more to do with their stimulation of the skin's tactile receptors.

30.    Ice baths can help reduce muscle soreness and maybe even avoid a drop in performance the day after a hard effort.  A large part of the benefits appear to come from the water pressure, not the temperature, so standing in a swimming pool might be nearly as good as sitting in an ice bath. If you do want cold temperatures, don't go below 50° F.

31.    A plyometric training program can boost running economy, even in runners who are already exceptionally fit.

32.    Hot water immersion is not particularly useful for runners.  It can help warm up a stiff muscle or tendon before a workout, but you shouldn't use heat on injured areas unless you ice after, and you definitely shouldn't use it on acute injuries.

33.    Contrast therapy—alternating between hot and cold water immersion—is a new technique that's becoming more popular, but it doesn't have a whole lot of evidence to support it.  It appears to work better than doing nothing after a hard effort, but it's not clear whether it's better than a regular ice bath.

34.    Explosive weight lifting and plyometric exercises are best at boosting running economy, while traditional heavy weight lifting benefits neuromuscular coordination in addition to economy.  Circuit training can improve general fitness and serves as a nonspecific precursor to hard anaerobic workouts.

35.    Lacing up your shoes snugly improves their fit, and using a "heel lock" lacing technique can increase the stability of your shoe and maybe even reduce your impact loading rate.
36.    A small leg length discrepancy can only be accurately measured by x-ray or CT scans, and even if you do have a true leg length difference, it's not clear whether heel lifts make a difference.

37.    Doing a small amount of running barefoot or in minimalist shoes a few times a week can improve the strength of some of the smaller muscles in your foot and lower leg, though whether this reduces injury rates is still very much up in the air.

38.    Because of the body's circadian cycle, athletic performance is significantly better in the late afternoon and evening than it is in the morning.  From studies in swimmers, it appears that performance could vary from morning to evening by as much as 3-5 seconds per mile!

39.    Missing a few hours of sleep on a single night is unlikely to impact your performance significantly, though it can increase your perceived exertion level.  However, chronic sleep deprivation leads to undesirable changes in hormone levels.

40.    Traveling across time zones can sap performance if you haven't adjusted to your new time zone, and traveling west is easier on the body than traveling east.  Using external cues like bright lights and meals high in protein can help key your body into a new time zone quicker.

41.    When exercising in cold weather, it is a lot easier to maintain your temperature than it is to bring it back up after it's dropped.  Dress a bit warmer than necessary when warming up for a competition in the cold, since you can always take something off.

42.    Loud, high-tempo music can increase motivation during measured exercise tests; one study even found the benefits carried over if you listen to music before your workout.  But the specifics of what to listen to and whether it will help improve performance outside of recreational athletes is untested.

43.    While short term increases in fitness from recent training wear off fairly quickly when you take time away from running, longer-term fitness stays surprisingly stable.  You appear to retain about half of your gains in fitness indefinately, or at least for several months even with no athletic activity.

44.    It makes sense to taper off your weight training in the weeks leading up to a big race, since highly specific weight strength isn't exactly desirable in a running race.  However, you should keep doing explosive and specific exercises like plyometrics closer to race day, since these are running specific.

45.    The majority of studies on arthritis rates in runners have found no increase in the rate of knee or hip osteoarthritis, and running is much safer than other sports which can cause traumatic knee injuries (which are strongly linked to knee osteoarthritis later in life).

46.    Surprisingly, doing some moderate running while you are sick with a cold does not seem to impact recovery time at all.  (Note: This is contrary to my own experience, where I've found that running while sick is quite bad for me!)

47.    Your vulnerability to upper-respiratory infections (like the common cold) follows a U-shaped curve based on your training intensity.  Light to moderate training bolsters your resistance to getting sick, but heavy training makes you more vulnerable to illness. 

48.    The spine seems well-adapted to handling the stresses of running.  Though your spine can temporarily shrink by as much as a quarter inch after a hard run, this doesn't seem to be connected to back problems.  In general, running does not appear to cause back problems, but can agitate back injuries that already exist.

49.    There is no good evidence to support the use of non-steroidal anti-inflammatories like Advil or Aleve when dealing with running injuries.  Many common running injuries aren't inflammatory at all, and there's some evidence that they can even inhibit healing!

50.    Injections of corticosteroids can be useful in some injuries, but carry a risk of causing ruptures in fascia and tendons.  You should consult your doctor about the risks and benefits of a corticosteroid injection before going ahead with it.

51.    Emerging evidence indicates that a class of antibiotics called fluoroquinolones, which are commonly used for ear infections, sore throats, and other common bacterial issues, carry a risk of inducing tendonitis or tendon rupture in the large tendons of the body, especially the Achilles.  It's unclear how these risks play out in athletes, so make sure your doctor knows about the risks of fluoroquinolone antibiotics like Cipro, Levaquin, and Avelox before prescribing them to you for a minor issue.

52.    Thyroid problems can be troublesome for athletes, since intense training appears to cause fluctuations in hormone levels.  There is unfortunately not much research on hypothyroidism in athletes, so the best advice for now is to closely monitor your hormone levels.

Hopefully you've learned something useful from this list too! I've regrettably been quite busy with work and other things recently, and I haven't been putting as much time into Running Writings as I should.  However, I'm on the cusp of some very exciting things which should get rolling in the next few weeks (fingers crossed), so check back often for updates.  You'll see I've already added a page on my booklets and publications, and I'll be adding a feature page for the Injury Series as well.

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