By Alan Baldwin

LONDON (Reuters) - To those who dip into swimming only when the Olympic Games come around, it may seem odd to hear a pool described as 'fast' when it looks much like any other large rectangle filled with water.

And while coaches hammer into their young charges that fast swimmers make fast pools, like swimmers, some pools are faster than others and even Michael Phelps goes quicker with the application of science.

In 2013, after British swimmers had flopped at the London Games and that year's world championships, head coach Bill Furniss suggested Sheffield's Ponds Forge Olympic standard pool was hampering their development because it was too fast.

Cue jokey headlines suggesting swimmers were training in the "wrong kind of water" -- an echo of the "wrong kind of snow/rain/sunshine" excuses familiar to downtrodden commuters when Britain's weather halts the trains.

At the international level, however, the biggest waves are the ones given by the swimmers to the crowd as they climb out.

Rio's new 50-metre Olympic pool, where records may be set as dreams and duels play out, should stand out like a gleaming Ferrari among functional family runabouts.

The technology in such a pool, from energy-absorbing lane dividers and wave-swallowing drainage to the depth and temperature, is all designed to help the world's best swimmers go faster than ever.

"Years and years ago, when pools had gutters on the side and walls, if you were on the outside lane then the waves were splashing back and hitting you," Britain's 4x100 mixed medley world gold medalist Chris Walker-Hebborn told Reuters at an Adidas event.

"That was what I perceived as a slow pool back then.

"Everything we race in now, it (the water) runs off the edge into a drain so you are at no more disadvantage being in lane eight than you are in lane four, other than not being in the middle of the race."

Beijing's 'Water Cube' was dubbed the fastest pool in the world when 25 world records were broken at the 2008 Olympics and various factors contributed to that.

The now-banned drag-reducing high-tech suits, with Phelps using Speedo's LZR bodysuit to win eight golds, were a huge factor but the pool was also wider and significantly deeper than the one used in Athens in 2004.

Unlike Athens, it was also indoors.

That uniform three meter depth, now recommended by world body FINA and considered the norm since Beijing, makes the water more buoyant and less turbulent.

The temperature of the water -- all 3.7 million liters of it -- is kept between 25 and 28 degrees Celsius. Too warm, and the body can over-relax, Too cold, and muscles may tighten.

The Rio Aquatics Stadium, a temporary structure, has had 15,000 strategically positioned holes drilled into it as part of a natural ventilation system.

The lighting, the crowd, the acoustics also all help create an atmosphere that crackles with anticipation and plays into the mental side. In Rio, the front-row seats will be just 10 meters from the action.

British swimmer Adam Peaty, who set a 100 meters breaststroke world record of 57.92 seconds in London last year, said the psychological factor of swimmers going fast because they know the pool is state-of-the-art was not to be underestimated.

"It's more of an idea than a thing; The idea of performing at an Olympics and being one of the best in the world, and that pool is the idea," Peaty said after this year's European championships.

"It sounds very metaphorical, but every time I see that (London) pool I just want to be the best in the world."

(Editing by Greg Stutchbury)