Vladimir Putin tends to project a strong image: Whether he’s riding a horse bare-chested, swimming every day, or walking with a powerful, confident gait, the 63-year-old exhibits the epitome of an iron-willed Russian leader.

Now, researchers have dug up some interesting facts about his famous “gunslinger” walk, in which he swings his left arm and leaves his right arm at his side when he walks. The unique gait is a characteristic Putin developed from weapons training in the KGB, according to the new study published in BMJ.

“We were struck to find several consecutive YouTube recordings of Russia’s president, Vladimir Putin, manifesting a clearly reduced right-sided arm swing,” the authors write in the introduction. “Putin’s distinctive walk has been debated previously, and different theories emerged, ranging from Erb’s palsy to intrauterine stroke.”

The researchers go on to note that most viewers would assume Putin was suffering from Parkinson’s disease — as a reduced right arm swing is a major symptom of the disease. But it turns out that Putin has no significant health problems, especially not Parkinson’s. In fact, the researchers surmised that the president has “excellent motor skills,” with no shaky handwriting or difficulty in lifting weights. The man is an intense workout machine, after all. What else could explain that left arm-swing, reduced right arm-swing walk?

It turns out, that walk is likely the result of Putin’s background in military training. “[T]rainees undergoing KGB training are taught to keep their right hand close to the chest even while walking, allowing them to quickly draw a gun when faced with a foe,” the researchers explained. “To support this case, it is essential to link the Russian officials to KGB membership, or at least to other forms of weaponry training.”

Indeed, Putin isn’t the only Russian official to manifest the gunslinger gait. Prime Minister Dmitry Medvedev, former ministers of defense Anatoly Serdyukov and Sergei Ivanov, as well as military commander Anatoly Sidorov have all been observed to walk in a similar fashion. Putin and Ivanov were both KGB officials, and it appears that the others also had some weaponry and military training.

One former Russian KGB manual actually instructs trainees to carry the weapon in the right hand, with your left side creating the forward motion. “When moving, it is absolutely necessary to keep your weapon against the chest or in the right hand,” a the manual states. “Moving forward should be done with one side, usually the left, turned somewhat in the direction of movement.”

The video below shows examples of Putin’s gunslinger walk.