Free Speed

Does carrying ice in your hands actually cool you off enough to improve performance in hot weather?

Now we're going to take a closer look at how much heat you naturally produce and expel during exercise. That will serve as our basis of comparison when determining if particular types of cooling garments actually live up to expectations.

All other forces being equal, nothing slows an athlete down more than the gradual buildup of heat in the body. To avoid overheating (and death!), the body has a variety of ways to dissipate heat during exercise. And here they are.

How does the body deal with heat during a race?

I know there are many different schools of thought on “the best way” to swim. I just have a technical question about one portion of the swim stroke--the glide. Or more precisely, “to glide or not to glide” is the question.

Physicist Jim Gourley examines triathlon's drafting rules - and finds that they could use improvement.

Physicist Jim Gourley examines triathlon's drafting rules - and finds that they could use improvement.

How much of a difference does drafting make in draft-legal triathlons?

Explaining running efficiency to someone without getting lost in horizontal and vertical forces is tough. Then it occurred to me that there's already an almost universally understood example of how changing the magnitude of our vertical and horizontal force components changes efficiency of movement. It's everyone's favorite smartphone game, Angry Birds.

How much slower are clip-on aerobars for triathlon bikes?

The illustrations you see in the book will help you visualize some of the more sophisticated topics and clarify what they mean to you as an athlete. Ironically, as simple as those illustrations make things for you, actually creating them was a challenging process that required several iterations.

A reader asks, "I've spent 6 years trying to swim faster and I can't get below 2:00 100s. Am I hopeless?" Jim Gourley replies, "Best. Question. EVER." See why.

A race strategy that includes predictions about what the elements are going to do has a better chance of surviving that first punch. It's certainly more helpful than a gremlin bell.

Their importance and prevalence in the book is best highlighted by a phrase that never appears—"scientifically proven." There is a very good reason for this, and for why you should always be wary any time you see them in a product advertisement. There is no such thing as "scientifically proven."

When riding your bike, your finish time will improve if you push harder into the wind and relax when you go with it. The trick is knowing just how much harder you can push and how much to relax...

We all like to think that we can buy gear or come up with a strategy to "cheat the wind." But the math shows that you cannot make up time lost riding into the wind by riding faster with the wind at your back. See why.

Riding your bike down a hill really fast does not make up for the time you lost while pedaling slowly up the other side. Here's why.

FASTER by Jim GourleyThere are plenty of books out there about triathlon training plans, nutrition, skills and mental toughness, but nothing about the science and physics that go into the sport of triathlon. To my knowledge, FASTER is the first book on the physics of triathlon.

Here, I’ll bust the myth of weight savings and reveal the truth about so-called “fast” bikes. To keep it quick, I’ll skip over some of the details that make FASTER a really interesting book.

So even after 116 years of Olympic swimming, we're still refining our scientific understanding of the best way to move through the water.

One of the more interesting, and perhaps unbelievable, scientific principles brought up in FASTER is the fact that a human uses the same amount of energy to run a given distance no matter how fast he or she runs. Seriously!

One of the things I discuss in FASTER is how engineering jargon has made its way into advertising.

Here's a scientifically rigorous way to select the next triathlon bike you are shopping for.

Here's a scientifically rigorous way to select the next triathlon bike you are shopping for.

Here's a scientifically rigorous way to select the next triathlon bike you are shopping for.

Paul A. asks, "If I am 5' 10", 148 lbs, and about 10% body fat, will losing more weight help me get faster or am I already at the limit?"

All in all, Strava performed fairly well.

How can a GPS-based mapping program possibly be accurate at estimating power? To find out, scientist Jim Gourley puts Strava to the test against his power meter.