Cardio showdown: Strongmen vs. marathoners

THANK YOU FOR VISITING SWEATSCIENCE.COM!

As of September 2017, new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.

- Alex Hutchinson (@sweatscience)

***

Who has a bigger heart: a 150-lb marathoner, or a 300-lb World’s Strongest Man competitor? And more importantly, whose heart is healthier? Believe it or not, this is an actual study just published in the Journal of Strength & Conditioning Research by scientists in Lithuania. They studied 8 Strongmen, 10 marathoners (nationally or internationally competitive in both cases), plus 9 controls.

In general, you wouldn’t expect strength training to do much for the heart — but these competitors are so extreme that you might expect to see some differences, the researchers argue:

Strongmen with their Herculean strength conduct extremely arduous exercises such as lifting, holding, carrying (hundreds of kilograms), pulling, and pushing (tons) during training and competitions, and such tasks trigger a pronounced cardiac pressure overload and, when conducted over an extended period of time, might be expected to impact cardiac size and function to a greater extent than participation in other types of resistance sport.

The results shows that the Strongmen do have big hearts, but pretty much exactly in proportion to their bodies, whereas marathoners have big hearts but small bodies. For example, the thickness of the posterior wall of the heart was, on average, 11.81, 11.82 and 10.99 mm in the Strongmen, marathoners and controls; but when adjusted relative to body surface area, the values were 7.50, 8.56 and 7.50. More to the point, the hearts of the Strongmen don’t appear to function quite as well (the “E/A” column is a measure of diastolic function):

The Strongmen also fared worse on measures of plasma lipids. What does this all mean? None of the results are particularly surprising. But I suppose if you’re a skinny little marathoner, it’s kind of cool to know that your heart is just as big as the dude twice your size single-handedly hauling an 18-wheeler up a hill on TV.

Usain Bolt and Paul Tergat, striding slowly

THANK YOU FOR VISITING SWEATSCIENCE.COM!

As of September 2017, new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.

- Alex Hutchinson (@sweatscience)

***

A couple of weeks ago, I asked if anyone had footage of fast runners running slowly. The reason: I was curious to see whether the well-known fact that fast runners take rapid strides is (a) because of the way they run, or (b) because of the speed they run at. The Runblogger, Pete Larson, just sent me a couple of great links showing two of fastest runners ever, jogging along comfortably: Usain Bolt and Paul Tergat.

My rough calculations showed Bolt taking 18 steps in 6.7 seconds, for a cadence of 161, and Tergat taking 8 steps in 2.8 seconds, for a cadence of 171. You can also watch Tergat at 1/3 speed here. For the same 8 steps, I get 8.5 seconds, for a cadence of 169 — so let’s say about 170 for Tergat.

The point? Just because they run their Olympic races with a relatively rapid cadence (257 for Bolt!) doesn’t mean they maintain that same cadence when they’re jogging along comfortably. (Okay, I promise I’m done with this topic, at least for a little while!)

 

Brain endurance, mitochondria, and the desire to exercise

THANK YOU FOR VISITING SWEATSCIENCE.COM!

As of September 2017, new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.

- Alex Hutchinson (@sweatscience)

***

Endurance training causes new mitochondria — the “power plants” that use oxygen and glucose to produce ATP — to grow in your muscles. This, in a nutshell, is why your endurance improves, because you’re able to keep your muscles aerobically fuelled for longer. These adaptations take place mainly in the muscles you use during training: legs for runners, arms and legs for swimmers, and so on.

But the muscles aren’t the only place where oxygen and glucose are needed: at rest, your brain sucks up 20 percent of your body’s oxygen supply and 25 percent of its glucose. A neat new study in the American Journal of Physiology (press release here; full text of study freely available here) suggests that aerobic exercise causes new mitochondria to grow in your brain as well as your muscles, which has a couple of interesting implications. The study was done in mice: an eight-week treadmill running program produced the usual changes (increased time to exhaustion, higher mitochondria in muscles), but also produced a series of changes suggesting that new mitochondria had grown in the brain.

One reason this is significant is that figuring out how to boost mitochondria in the brain would be helpful for “various central nervous system diseases and age-related dementia that are often characterized by mitochondrial dysfunction.” That includes, for example, Alzheimer’s disease.

The other is the possible role of brain mitochondria in “central fatigue,” which the researchers define as “the progressive reduction in voluntary drive to motor neurons during exercise” (this is a controversial topic, I should note). The idea is that your body’s absolute top priority is making sure that your brain ALWAYS has enough energy. During intense exercise, your muscles are using oxygen and energy so rapidly that your brain’s oxygen levels start to drop. To prevent disaster, your brain automatically starts to recruit fewer muscle fibres for a given level of effort, so that more resources can be diverted to the brain. You experience this as fatigue: you’re pushing just as hard as before, but you’re getting slower/weaker. But if you have more mitochondria in your brain, you can make use of available energy more efficiently so you won’t have to shut down your muscles quite as soon:

[I]t is reasonable to hypothesize that increased brain mitochondria may play an important role in reducing fatigue through their influence on cerebral energy status.

Another interesting wrinkle in the discussion:

We have also shown a positive association among brain mitochondrial biogenesis [i.e. growing new mitochondria in the brain], voluntary activity and endurance capacity…

What they mean by “voluntary activity” is how much mice, when left to their own devices, decide to run on a wheel in their cage. Researchers have found that the “impulse to exercise” tends to decline with age — so before your body starts to fail, your brain just isn’t as enthusiastic about doing lots of exercise as it used to be. There are some possible hints here that this phenomenon could be linked to declining levels of brain mitochondria. In other words, regular exercise doesn’t just preserve your ability to exercise — it also preserves your desire.

Static stretching before cycling makes you less efficient

THANK YOU FOR VISITING SWEATSCIENCE.COM!

As of September 2017, new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.

- Alex Hutchinson (@sweatscience)

***

I wrote a few months ago about an Italian study showing that static stretching hurts cycling performance — that was the first study I’d seen about stretching and cycling, joining a whole bunch of studies showing that stretching hurts speed, power and endurance in running. Now researchers at Cal State Fullerton have backed up that initial result with a slightly different study, published in the Journal of Strength & Conditioning Research, that reaches basically the same conclusion.

The study was very simple: 10 highly trained cyclists (5 men, 5 women) did two 30-minute rides at 65% VO2max pace, while the researchers measured economy (i.e. how much oxygen they needed to maintain the pace), perceived exertion, and heart rate. Before one of the rides, they did a standard 16-minute static stretching routine. Here are the results for oxygen use (squares indicate the non-stretching trial):

Pretty straightforward: after stretching, it took more oxygen to maintain the same pace. Note that the difference was statistically significant only at the five-minute mark, not for the rest of the data points, indicating that the effect gradually wears off. Perceived exertion was the same in both trials — so the volunteers felt the same, but their bodies were working less efficiently.

Why does this happen? The researchers write that the results “may be explained through either muscle mechanics or neural factors or a combination of the two.” Then they spend a few pages going through all the various muscle-related theories and the various brain/nerve-related theories. The short answer is that no one knows. One of the previous neural studies they mentioned was interesting, and I wasn’t familiar with it:

Cramer et al. (4) proposed neural factors, such as decreased muscle activation or altered reflex sensitivity, might be the primary mechanism underlying the stretching-induced decreases in force. After stretching only one leg, they reported the same pattern of stretch-induced decrease in both stretched and un-stretched limbs...

That’s pretty cool! It certainly suggests that, whatever is going on in the muscles, there’s also something going on in the nervous system. Bottom line is simple — and by now, should be no surprise: don’t static stretch before workouts or races. It hinders performance.

A plug, a thank you, and a look ahead

THANK YOU FOR VISITING SWEATSCIENCE.COM!

As of September 2017, new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.

- Alex Hutchinson (@sweatscience)

***

Sweat Science is now 2.5 years old – not a round number, but a good enough reason to pause for a brief navel-gazing interlude.

Looking back: I started this site with an “old-media” attitude, intending to use it to broadcast various tidbits that I came across while reporting newspaper and magazine stories. The site has evolved as its readership has grown, it’s now just as likely to go the other way: the questions and discussions (and yes, critiques!) that I get from Sweat Science readers frequently lead to or inform articles I later write for other venues. So I’d like to take a moment to sincerely thank all of you who visit the site, and especially those who have shared their thoughts in the comments section.

Looking ahead: Over the past few months, I’ve been contemplating the future of the blog now that my book has been published. Maintaining the blog was a natural fit while my main “day job” was researching and writing a book about the science of fitness. After thinking carefully about how I’d most enjoy spending my days over the next few years, I’ve decided that I’d like my next book to fit in a similar genre. I’ve chosen a topic that I believe focuses on the most interesting area of research into the science of human physical capabilities, and I’m starting work on a book proposal. If this proposal is accepted, my research will ensure that I have a steady supply of cool new sports and fitness science research to blog about here!

A plug: So here’s the favour I have to ask. When my agent takes the book proposal to publishers in a few months, the very first thing publishers will do is look up the sales figures for my current book, Which Comes First, Cardio or Weights? (see reviews here; links to order here). Literally every copy will count. So I’m hoping that, if you enjoy the blog, you’ll consider picking up a copy of the book. Or recommending it to friends, or buying it as a Christmas gift. It’s available for as little as $10 U.S. or $15 Canadian. If you’ve already bought the book, then thank you very much for your support! – and please consider sharing your impressions with a review on Amazon or a similar site.

Again, thanks for spending some of your time here – I’ve really enjoyed the past 2.5 years, and I’m looking forward to the next 2.5!