Bushmen trackers in Namibia... they are a tiny people, but can outrun anyone carrying a 4.5kg R1 or FN rifle.
The 2.4km run time test is routinely used in military training programmes all over the world as an indicator of aerobic capacity and its possible improvement. The following was published in the South African Medical Journal: "Assessment of the 2.4km run as a predictor of aerobic capacity" by Burger, Bertram & Stewart. The conclusion:
"It is concluded that in the population of military personnel studied, a 2,4 km timed out-and-back run test correlates significantly with, and reliably predicts, the directly measured VOzmax, and is therefore a reliable alternative measure of aerobic capacity."
Koevoet (crow-bar) trackers on the spoor - South West Africa Police Counter-Insurgency Unit (SWAPOL-COIN), was a very successful 'infamous' paramilitary-trained police counter insurgency unit during the South African Border War.
I used to run it under 10 minutes ... age 19. It is my aim to run it under 10 minutes again, with a 4.5kg rifle and boots ... age 45. I think it is possible as I ran a 2.4km a few months ago with standard running gear, under 11:10 ... the qualifying time for the Australian Defence Force for under 25's. I was around 12 kg's 'overweight' and not particularly fit. All three my kids, under 16 years of age, can run the 2.4km under 11:10.
The standard fitness test was the 2.4km run ... followed by an immediate session of pull-ups, sit-ups and push-ups ... a time limit of 2 minutes for each. Running with a rifle in hand changes the whole game, as you need more upper body strength to compensate for the lack of 'arm action' required in normal running.
Most people don't realise their own potential or their own physical design. Humans were designed for running, right from the shape of your foot, your buttock muscles, the position of your head and your 'hairless skin.' You are designed to run in the heat of the day and to run any antelope into the ground. A fit human being can outrun a horse on a 80km run.
Most people think that running is hard on the joints, especially the knees. This is a total misconception, due to our lack of running in early years, especially barefoot running. If there is a 'running killer' ... then it is the shoe, especially the 'modern' running shoe ... the reason the average 'First World' white guy is outrun by the average 'Third World' black guy ... it's all in the feet.
Heel striking and weak foot structure is the main reason for running 'complications' ... as most of us don't know how to run anymore. 'Heel striking' is possible today, because of the 'false protection' and the high heels our 'running shoes' provide. It is impossible to run like that barefoot. Therefore the need for barefoot training, whether it is running, skipping, climbing or other exercises. The human foot is designed for rough terrain. The biggest killer for foot strength is even surfaces.
Due to our 'lifestyle' and other commitments, it is hard to cover the daily 19km's our hunter-gatherer ancestors covered ... but it is possible to run your 2.4km and do the other strength exercises. It only takes about 20 minutes to do the whole lot. It is possible ...