Here’s an idea for police officers who want to get fit: how about practicing karate while standing knee-deep in the ocean in the middle of winter?

Police in central Japan are doing just that, building their endurance by training at a frigid winter beach.

The officers serve on the police force of Obama City, a town that became known to the wider world during the 2008 US presidential election.

21 officers practiced karate in freezing temperatures.

One officer said it was so cold his feet went numb.

Another officer said he hopes the training will turn him into a reliable officer able to protect residents.

And if President Obama ever visits, he can rest assured that his security will be in cool hands.

The midwinter beach training continues for the next two weeks.