KGB gun training has given Putin a certain swagger

The specialists, who analyse postures and movements that are potential signs of health disorders, say they were struck by Mr Putin's "distinct" way of walking.

The peculiar walk of one Vladimir Putin (left arm swinging naturally, right arm stiff at his side) has been the subject of speculation, with guesses ranging from childhood illness to an in-utero stroke, Live Science reports. The researchers evaluated footage of Putin performing a number of different activities, and pronounced his motor skills "excellent".

However, after studying several videos of Putin they found no other symptoms of nervous system disease, such as tremors or lack of coordination.

Researchers found a training manual for the Russian security agency, now known as the FSB, and pinpointed a section that instructs operatives to "keep their weapon in their right hand close to their chest and to move forward with one side, usually the left".

"Trainees are taught to keep their right hand close to the chest while walking, allowing them to quickly draw a gun when faced with a foe".

The researchers were "stunned" by what they saw, said Bastiaan Bloem, a professor of movement disorder neurology at Radboud University Medical Centre in Nijmegen, the Netherlands, who led the study.

Experts discovered that the Russian President, Prime Minister Dmitry Medvedev, two former Ministers of Defence, Anatoly Serdyukov and Sergei Ivanov, and Anatoly Sidorov, a highly ranked military commander, all walk in the same way.

Medvedev, it notes, was never trained by the KGB or Russia's military, but may just be trying to mimic his boss. So why would he walk like Putin?

Rather than interpreting this gait pattern as being pathological, "we feel that there is another - and perhaps more plausible - explanation, namely a behavioural adaptation resulting from military or intelligence training", write the authors.

They found other examples of a reduced arm swing in cowboys depicted in Wild West films. The study says KGB-style firearms training would explain the "gunslinger gait".

Bloem told AFP that in Putin's case the arm swing could "in part be overlearned". A new study says it could be a sign of his KGB training. But it didn't take long for them to rule out Parkinson's as a cause for Putin's unusual gait. "What we are putting forward, but very cautiously, is a new hypothesis".