Having declared that it doesn't matter what you wear when you run, I'm going to say it actually kind of does.
For comfort and performance, definitely. As the saying goes: "It's not poor weather, it's poor choice of clothing."
And for looks it matters, because dressing the part is likely to inspire you to work out more - and potentially meet your life partner*.
Sportswear brands led by great rivals adidas and Nike have been mindful of this for years, pouring loads of money into developing fabrics to improve the athlete's experience and performance, while at the same time trying to be fashion-forward. They've done such a good job that right now, 'activewear' (yes, it has its own category) is one of the most profitable niche sectors in the global fashion market.
For proof, witness these old adidas catalogues. The selected images demonstrate that A) it's a good thing that the 70s and 80s are behind us and B) sportswear has always tried to be at the cutting edge of technological excellence.
For example, in 1979, cotton was the rage for fashion-conscious runners (above), but by 1982 synthetics had arrived, best worn tucked in and pulled up nice and high (below).
I spoke with adidas's global director of running apparel, Craig Vanderoef, to get the lowdown on where running gear has been, and where it is headed next.
The Long Run: Tell us about the evolution of activewear.
Craig Vanderoef: The first running boom happened (in the 1970s) in the US when marathoners and Olympians like and dominated the sport. Apparel was very much "team issued"; it worked for many sports at once and really lacked the sport-specific needs of runners. It was about heavy-duty cottons that could stand up to industrial washing and soak up the sweat. But this also meant pain. Cotton on a long run becomes heavy and abrasive. Running is hard enough, we just wanted all of the pain to come from effort, not the apparel.
So the technical or functional age of apparel came about when the runners themselves started to ask for more. Shorter was the American pioneer of running performance (he used to run in women's nylons in the winter to stay warm) and Ron Hill in the UK was the man who revolutionised fabrics and materials. These men looked at the functional needs of running and runners, and made sure they had options to suit the hot, the cold the wet, and the windy.
This age gave us seamless constructions, waterproof breathable fabrics, and from the minds of innovators like Stan Mavis, we made the climate a part of what you chose to wear - not whether or not you chose to run.
This era also ushered in women's specific performance gear such as the sports bra ... the original really was two jock straps sewn together (not exactly an innovation!).
Around 2005, women really started to dominate the running scene, which led to another modern age of running apparel in which style was even more important.
What's the difference now?
The change to the modern era is being driven completely by gender and style. When women joined the running world, they needed performance. Now that they dominate it, they expect performance but they demand style. In my opinion, men also need to dress better because they might just run into the woman of their dreams on the run. It is social, it is about being fit, and women are competitive. They want to be the best runner they can be; the best dressed they can be; and in general feel confident and stylish.
So as women started running, it became more popular. Men started running more to be around the women who were running more, and now running had become a great way to meet someone.
The runner demands to look great on the run with the performance of the functional age and the wearability and style of the modern age. Running spills into the runner's life and the apparel needs to be ready for it.
Has women's running apparel changed more than men's?
Women's apparel had further to come because "shrink it and pink it" drove athletics apparel through the functional age, but both are undergoing some really great changes in the modern era of running apparel. Women's running is closer to the couture line than men's, but that is the case in the office as well as at the gym.
What's the latest, most exciting breakthrough in fabric technology?
Cooling the body in hot weather has always been the Holy Grail; we can keep you warm, dry, and wind-protected, but the ability to keep runners cooler on hot days was the big problem to solve. In April of 2014, adidas introduced ClimaChill, which is an amazingly breathable fabric that utilises cooling yarns to keep the athlete comfortable and cooler.
It actually keeps you cooler than not wearing a shirt, so I like to say that Clima Chill is better than naked, but not as much fun.
Where is running apparel heading?
The next age in running apparel is the interactive and adaptive age. These are garments that adapt to the runner and the runner's environment to keep the athlete comfortable and focused on their run, not their body temperature. In the next age one shirt will adapt to the temperature so you don't need to change.
At Nike, runners such as college track star Steve Prefontaine (above) inspired technical innovation from the company's beginning as a shoe specialist in 1971. A research lab opened in 1980 in response to the running boom of the late 1970s, which worked with runners to make the best products.
Nike's current top technical fabric is Dri-FIT, which assists the body's natural ability to regulate temperature when running in a variety of conditions.
Are you a believer in high-performance running gear?
* I actually met my fiancé on the starting line of the LA Marathon and we started talking about clothes right then and there.