Naked Science Forum

Life Sciences => Physiology & Medicine => Topic started by: thedoc on 21/03/2012 09:13:02

Title: What aren't runners all tall?
Post by: thedoc on 21/03/2012 09:13:02

GAMEL JOHN  asked the Naked Scientists:
   
Here are a couple of question you might be interested in.  Why aren't the world's greatest runners extremely tall, since they travel so much farther with each stride than a short athlete? In fact, great sprinters tend to be average or not much more in height, while marathon champions are often short.
 
In the same vein, why aren't the great heavyweight boxers really huge? Muhammad Ali (after whom a street in my town of Louisville is named) was only 6'3", so why couldn't some guy who was seven feet tall and weighed 350 pounds knock him out of the ring?
 
I'll bet a sports physiologist could answer these questions.
 
John Gamel, MD


What do you think?

Title: Re: What aren't runners all tall?
Post by: diverjohn on 04/10/2017 21:03:30

Well, I run marathons. The world's best marathon runners are typically 5'7" tall, 30 years old, and 120 pounds.
The key quality has to do with relating how the runners legs swing from this hip to the way a pendulum swings from its pivot.
1. The longer leg and larger foot require more energy to move through an arc.
2. the long distance runner is better to have a short quick stride than a long stride. The short distance racers will use the long stride.
3. In hot weather, the ratio of skin area to body volume favors the smaller athlete as far as heat disposal goes. Look at the women's marathon at the Athens Olympics, where world champion Paula Radcliff (5'8" tall, 119 pounds) succumbed to the heat and stomach troubles, and allowed the petit Japanese racer to win.

Title: Re: What aren't runners all tall?
Post by: kazbert on 05/10/2017 01:07:47

It takes less energy to move 120 pounds across 26 miles than to move 170 pounds that same distance.

Title: Re: What aren't runners all tall?
Post by: Kryptid on 05/10/2017 02:58:06

You could also consider how weight scales with height. Doubling the height of an entity will increase its strength four-fold but it's weight will increase eight-fold. Pound-for-pound, that makes bigger things have a lower strength-to-weight ratio than smaller things. I know taller people are not proportioned exactly like short people, so I don't think we can say that an 8-foot tall person is exactly four times stronger than a 4-foot tall person. Nonetheless, I think it's accurate enough to say that strength-to-weight ratio does indeed decrease somewhat with increasing height for a person. Taller people would also have more drag than shorter people (if that matters much at the speeds humans run).

Title: Re: What aren't runners all tall?
Post by: Colin2B on 05/10/2017 09:55:44

Tall thin young men are susceptible to spontaneous pneumothorax, early symptom shortness of breath and pain at top of inspiration. For every one hospitalised I wonder how many get mild symptoms and put it down to stitch etc and are put off running. I'm assuming mild/early stage might self heal.
Anyone know more about mild cases?