Devolution?

According to The Telegraph...

'Men today are the weakest in history and would have been no match for our ancestors in a battle of strength or speed, research suggests.

Peter McAllister, the author of Manthropology: the Science of Inadequate Modern Man, described today’s males as the “sorriest cohort of masculine Homo sapiens to ever walk the planet”.

By analysing sets of footprints preserved in a fossilised claypan lake bed, Mr McAllister concluded that Australian aboriginals 20,000 years ago reached speeds of 23mph on soft, muddy ground.

Bolt, by comparison, reached a top speed of 26mph at last year's Beijing Olympics during his then world 100 metres record of 9.69 seconds.

Mr McAllister claims that with modern training, spiked shoes and rubberised tracks, aboriginal hunters might have reached speeds of 28mph - faster than Bolt's record-breaking 100m performance at the World Championships in Berlin this summer.'

How does this square with the 'survival of the fittest' model as proposed by Darwin/Dawkins/Darkins? If men are physically weaker and can't run as fast as they used to be able to run, does that mean man has evolved to be a bit weaker? Is being physically weaker an improvement in the species? Or have we simply evolved to put our feet on the sofa, have a cup of tea and watch Coronation Street?