Saturday, May 31, 2014

Hot Drink Cools You Faster Than A Cold Drink?

Picture by Hogansville Coffee Co from Flickr
Really? Sure or not? That was my exact first reaction when I was saw this article. On second thought, I definitely do recall seeing all the ah peks (or elderly men for my overseas readers) sipping a hot coffee/ tea while sitting beneath a ceiling fan in our neighbourhood coffee shops in the sweltering heat.

Many past studies point to the very obvious fact that cold drinks lower your core temperature more than hot drinks. It now appears these previous studies used a flawed method to measure core temperature.

Under certain circumstances, a hot drink really does cools you more than a cold drink. Please read on to find out how this can help you exercise or race better in hot conditions.

The researchers in the study had their subjects perform a series of moderate effort cycling in their lab while drinking water at 1.5, 10, 37 or 50 degree celsius.

Unlike other studies using just a rectal thermometer to measure core temperature, the researchers used eight different thermometers on various body parts plus a rectal thermometer and another inserted through the nose down to the oesophagus to get a much more accurate reading.

Rectal thermometer??!! I don't know about you, I definitely will not volunteer for this study if I have to stick a thermometer inside my butt.

A rectal thermometer alone may register a lower temperature if you drink a large glass of ice water since the rectal thermometer measures the cold drink in your stomach (even though the rest of your body may not have cooled).

Sweating is the most effective tool your body has to get rid of excess heat. The study found that drinking hot water triggered a sweat response that more than compensated for the heat of the drink.

Cold drinks on the other hand produced the opposite response, a reduction in sweat cancelling the cooling power of the cold drink.

Does this mean you should drink a hot drink on a hot day to cool off? Well, the only caveat is your sweat must fully evaporate in order to produced the desired cooling effect. If you are exercising hard, or in a super humid environment (like in Singapore where it's often in excess of 90% humidity), you may sweat more than the sweat can evaporate. No point sweating more then. If your extra sweat just drips onto the floor then you're better off drinking a cold drink.

How does this information help you perform better in your race here in Singapore? The authors suggests ingesting a slushie before your exercise or race as this definitely produces a measurable drop in your core temperature as heat from your body is drawn to transform a solid (the ice in your slushie) to a liquid (water).

Picture of slushie by wwerewolf from Flickr
Reference

Bain AR, Lesperance NC and Jay O. (2012). Body Heat Storage During Physical Activity Is Lower With Hot Fluid Ingestion Under Conditions That Permit Full Evaporation. Acta physiologica. DOI: 10.1111/j.1748-1716.2012.02452.x


Sunday, May 25, 2014

Running Form (And Heel Strike) Of The Tamahumara Indians

Picture from http://www.chrismcdougall.com/
Last week's Sunday Times article discussed whether runners were still in favour of Vibrams. Here's a related topic this week after I chanced upon another article by Harvard professor Daniel Lieberman. He had published a landmark article reviewing whether landing patterns (of Kenyan runners) while running barefoot or running with shoes produced more forces.
Lieberman is now studying the Tarahumara Indians in Mexico's Copper Canyon. The Tarahumara Indians and Copper Canyon where they live form the framework of Chris McDougall's best-selling book Born To Run - the book that launch barefoot and minimalist shoe running.

Lieberman compares the running style of the hurache wearing Tarahumara men/ women who wore huraches (leather or car-tyre soled sandals) with the slightly younger Tarahumara Indians who have grown up wearing mostly western styled shoes. 
Hurache - picture from http://www.chrismcdougall.com/
Both groups of runners did not differ in height, body weight or leg length, although the Western style shoes (WS) Tarahumara were on average eight years younger. 75 % of WS runners landed on their heels while only 30 % of the hurache (HS) shod runners did so. 

HS runners were also less likely to over stride compared to the WS runners, i.e. less likely to have their foot in front of the knee while the foot contacts the ground despite no significant difference between the 2 groups when comparing stride frequency. 

HS runners also had flexed knees and hips while their ankles seemed to point down more. (All these are clues to using the bigger hip muscles and less of the smaller leg muscles while running - my personal opinion and not Lieberman's).

Lieberman also found evidence to suggest that HS runners seemed to have stiffer arches- suggesting they had stronger intrinsic foot muscles which may mean fewer injuries.

Perhaps weary and wary of how runners interpret his research, Lieberman took the effort to say that "there is much more to running form than heel strike type," and "many limitations caution against over-interpreting the results of this study." 

He went on to say that for the majority of us runners (you and I) who grew up wearing conventional shoes rarely run ultramarathons anyway, so his research paper on hurache wearing Tarahumara Indians who mostly avoid heel landing is not justification for anyone to switch to minimal shoes to stop heel striking.

Reference

Liberman DE (2014). Strike Type Variation Among Tarahumara Indians In Minimal Sandals Versus Conventional Running Shoes. J Sport and Health Science

Mother and son in Copper Canyon (by glasspondstudio fr Flikr)

Sunday, May 18, 2014

Today's Straits Times Article 180514

Have a look at page 17 of today's Sunday Times under the Home section and you'll see Sports Solutions quoted in the article. The journalist asked about our views on the Vibram Five Fingers lawsuit, the health benefits and also the general vibe of the running community regarding this case.

I was quoted as saying the evidence for barefoot or minimalist style is actually very sound provided the wearer's running technique is correct.

Using results of Daniel Liberman's study, runners who land correctly in their running technique will have benefits as impact is a lot less (even less than landing on your heels with cushioned shoes on).  If you land wrongly (with minimalist shoes) the impact is 7 times greater thus greatly increasing the chance of injury. See picture below.

From Liberman's article
Unfortunately most of us (runners) are very impatient for results and do not master the correct running/ landing technique while just using minimalist shoes thinking that will be sufficient.

Also read why if you run in more cushioned/ expensive shoes, the more likely you seem to get injured to further support why running in minimalist shoes with correct technique is superior to running with cushioned/ expensive shoes.

Reference 

Liberman DE, Venkadesan M et al (2010). Foot Strike Patterns and Collision Forces in Habitually Barefoot Versus Shod Runners. Nature. Jan 463(7280): 531-535.

Email me if you want the article.

My own minimalist running shoe in the picture below. My brother bought it for me from Shanghai for $RMB30 (or S$6) , much cheaper than Vibrams ($149-$209 here in Singapore).

Like I've always said and written, it's not what shoes you wear, its your technique that's more important.

Tuesday, May 13, 2014

Skechers Named Hottest Major Brand

Klefizighi wins Boston in his Skeches (Picture by Taylor Hartz)
Is Skechers becoming a genuine running brand? Yes, the company was once know for its fashion and lifestyle shoes, but after Meb Keflezighi won this year's Boston marathon in a pair of Skechers, (the 1st American to win in 31 years), the brand is starting to turn heads as a serious running shoe.

Keflezighi (who won silver in the 2004 Olympic marathon event) is a Skechers sponsored athlete. With his victory in Boston, Skechers has definitely become a genuine running brand. In fact, Skechers was named as "the hottest major brand" in US by Footwear Industry Expert on 12/5/14.  Skechers recently displaced New Balance at number 5 for top athletic shoe companies for market share.

What's more,the day after the race a Washington Post headline said "Skechers beat Nike in Boston Marathon."

Skechers has been around for 22 years, previously known for its lifestyle and fashion shoes. They even had Britney Spears and Joe Motana endorsing their shoes previously.

 Just like Vibram who recently had to pay damages for unfounded claims, Skechers' Shape-up shoe had suggested that "it would help people lose weight and strengthen and tone their buttocks, legs and abdominal muscles" and affected the company's reputation. Skechers had to pay $40 million to settle charges in 2012.

Skechers signed Keflezighi up in 2011 (he was 36 then and had just been dropped by Nike) as it made its first venture into the running shoe market, targeting walkers, runners and triathletes.

Kleflezighi provided the company with all the input regarding running shoes, from the fit to the laces, the lining, thickness, every spec you can think of. He finished 6th at the 2011 New York City marathon, but speciality running shoe retailers (those in touch with the hard core running community) remained wary (both in US and Singapore).

Skechers has since signed Kara Goucher , another elite female marathoner (previously with Nike as well) to its ranks, probably targeting female runners to use their shoes.

Even Wall Street is taking notice. On the day of the Boston marathon on 21/4/14, SKX opened at $35.59, four hours after Keflezighi's victory, the stock closed at $35.92 (up 63 cents). And it's been climbing since. I just checked, last night it closed at $42.22.

How will Skechers fare? I haven't tried any of the running shoes to comment on their running shoes. Only time will tell.

Even dogs are donning Skechers (http://blog.skechers.com/tag/super-bowl-2013/)