Its a fitness endurance test. Recruits need a certain level of fitness, the level that would enable them to run 10 miles for example. So you test them on that.Why? When will they need to run 10 miles? Id have thought sprint tests would be far more useful. Sprint tests and then carrying the 35kg dog makes sense. Lots of cases when that could come up. 0 where any officer anywhere will have to run 10 miles.