Despite the huge technological advances in military technology over the last few decades, the fitness and well-being of the individual soldier remains a key issue for military commanders. It's all well and good spending millions - even billions - of dollars on the latest technological marvel, but if you haven't got fit and robust servicemen to operate it, then it's worthless on the battlefield.
Over a decade of war in Iraq and Afghanistan has highlighted just how important physical fitness is for the armed forces. In both theatres, infantry soldiers would be working around the clock in temperatures often reaching 120 degrees Fahrenheit, carrying an extraordinary amount of equipment. Loads carried by soldiers would often exceed 50kg, double the 25kg carried in training.
In Afghanistan, vast areas were not suited for vehicles so soldiers patrolled on foot instead. That meant soldiers had to build up endurance for the gruelling task of patrolling but also have enough energy left for huge bursts of activity if fighting broke out. In essence, soldiers need the endurance of a marathon runner, the sprinting speed of Usain Bolt and the strength of an Icelandic strongman.
That might seem impossible, but time and again soldiers in Iraq and Afghanistan have demonstrated their remarkable ability to test the boundaries of their physical and mental limits. It's part of an ingrained military philosophy, fostered from day one of basic training, to 'dig deep' and push harder. As the classic phrase barked at new recruits by their physical training instructors (PTIs) would have it, "Pain is weakness leaving the body!"
Is the physical burden too much?
The human body does have its limits and some commanders worry that the physical burden placed on soldiers is simply too much.
Writing in 2011 for the British Army Review, an in-house journal for the British Armed Forces, an unnamed officer noted that soldiers were now laden with so much kit they were unable to launch effective attacks on the enemy. "We're getting to a point where we are losing as many men making mistakes because they are exhausted from carrying armour (and the things that go with it) than are saved by it," he wrote.
British soldiers could soon be donning the Oculus Rift virtual reality headset to train for medical emergencies on the battlefield.
The officer revealed that the Taliban nicknamed British soldiers "donkeys" because they have to carry all of their equipment on their back. On average, an infantryman in Helmand was carrying just over 60% of his bodyweight (ironically, under UK law a donkey can only carry 30% of its bodyweight).
"One of the real killers in Afghanistan is stopping every few yards, going down on to one knee, bringing your weapon up for a look around, and then standing up again, all with a full load," said one PTI. "We're not physically prepared for that and it's hurting a lot of guys.".
An increasing physical burden is not just a problem that has affected the British Army. The US Army has also suffered from increasing equipment loads and the resulting physical demands on the human body. A report in 2011 found the number of US soldiers who were medically discharged from the army with at least one musculoskeletal condition had increased "nearly ten fold" from 2003 to 2009. An increasing number of young, normally healthy soldiers were suffering from degenerative arthritis, cervical strains and spinal injuries. One soldier, Spc. Joseph Chroniger, who served in Iraq, developed bone spurs caused by a degenerative arthritic condition.
"I'm only 25 years old," Chroniger told the Army Times. "Arthritis is supposed to happen when you get old. What's it going to be like when I'm 50 or 60?"
In June, the US Army's Natick Soldier Research, Development and Engineering Center (NSRDEC) announced a detailed study looking at how fatigue affects both the mind and body of a soldier. The aim is to develop predictive models of soldier performance, especially while carrying heavy loads. The study is now in its second phase concentrating on how fatigue affects troops.
"I like to say that soldiers are like athletes," says Dr Leif Hasselquist, a NSRDEC biomechanist. "Except athletes perform and they're done. Soldiers have to do a six to twelve mile road march and then they have to perform, so you want them optimised. If we can find strategies to mitigate or predict how fatigue from load carriage affects the soldier, our research will be helpful."
Data gathered in the study will eventually be used to improve future load carriage strategies, route-planning tools, soldier performance expectations and improvements to equipment.
Soldiers take matters into their own hands
There's also been a concerted effort between the military and industry to reduce the soldier's load through technological innovation. It has long been thought that weight could be reduced in batteries and power generation, especially with renewable sources such as solar and heat energy. Helmets and body armour have also passed through several iterations where crucial kilograms have been shaved off.
But much of the technology is in the very early developmental stage and has never passed the point where it is cheap enough to be used by the armed forces. An electricity-generating backpack, unveiled in 2005, was billed as a 'revolutionary' new way for soldiers to power their equipment and reduce the burden of carrying multiple batteries. But ten years on and soldiers are still using a regular, non-power generating lump of a rucksack.
With technology failing to meet the demand for lighter loads, it's fallen on soldiers to try and mitigate the extreme physical demands placed on them. That's meant an upsurge in the use of performance-enhancing drugs and commercial supplements.
Worryingly, soldiers looking to push their physical fitness boundaries have taken a leaf out of Lance Armstrong's book and started to dabble with illegal performance-enhancing drugs. Particularly troubling is a growing trend in the use of anabolic steroids, a drug with several nasty side-effects, which increase muscle growth and enable soldiers to train harder.
Taking steroids is seen as part of an army culture which embraces the male 'Adonis body syndrome' and the macho nature of soldiering. British soldiers refer to it as 'Op Massive', using all possible hours of the day -- especially on operations -- to lift heavy weights and take performance enhancing supplements. Op Massive is the soldier's response to the physical challenges the army throws at them, with an unhealthy dose of vanity thrown in too.
The lethal effects of performance enhancements
So what's wrong with soldiers trying to get super fit? If they can perform their job and lower the chances of suffering exhaustion or fatigue, then that's a good thing, right? Not exactly.
Body-worn health monitoring systems measure physiological signals in real time to track individuals’ physical condition and performance.
In 2013, three reservists taking part in the arduous selection process for the SAS collapsed and died in Wales. The process is one of the most physically demanding selection processes in the world, and its culmination is a 40 mile loaded march over the Brecon Beacons with nearly 30kg on your back. "The course is conducted at the edge of human endurance," Tim Collins, a former British Army Colonel, wrote.
The deaths of the reservists - who were marching on one of the hottest days of the year - were closely followed by speculation that the soldiers were taking a 'cocktail' of performance-enhancing substances. These included energy supplements, body building products and ephedrine, a stimulant drug similar to methamphetamine.
On top of this, commanders are worried buff soldiers will actually be a hindrance on the battlefield, not a help, simply because they would be too heavy to carry if they became a casualty.
The use of performance enhancers has not been lost on the military and studies have been undertaken to look at their effects. Ten years ago, the Defense Advanced Research Projects Agency's Peak Soldier Performance Program looked at ways to enhance soldier fitness. Many findings were put on the shelf but others have found their way onto the frontline, including a caffeine gum which provides a quick burst of energy.
Army food is not supplemented with additional nutrients such as protein to build muscles or aid recovery. "We don't really do that," explains Jeremy Whitsitt, a team leader at the Pentagon's Combat Feeding Directorate. "Our main concern with warfighters is maintaining their energy so you will find that the rations are slightly higher in fat than they would be in proteins."
Currently, there is no 'holy grail' for soldier fitness, whether that's in terms of supplements or technological innovation. As the wars in Afghanistan and Iraq have shown, soldiers can perform arduous tasks if they are asked to do it. But that still requires a significant amount of old-fashioned boot camp training such as runs, loaded marches and a strong mindset. Physical demands may lessen in the future but the need to be fit, strong and active will always be there.