March 11, 2012: The U.S. Army has been trying to reduce the load infantrymen carry into combat. This has proved difficult, no, make that extremely difficult. The problem began with the appearance, in the late 1980s and early 1990s, of new body armor that offered better protection. The new "protective vest" was heavier and bulkier, thus inducing fatigue and hindering mobility. This often led to battlefield situations where a less tired and more agile infantryman could have avoided injury. Military and political leaders usually do not appreciate this angle. But the troops do, as it is a matter of life and death for them.

Recently, the army commissioned a thorough study of the armor weight problem and concluded that, even with the most optimistic development of new armor and protective vest designs, the weight of the vest could be reduced, at best, 20 percent and, more likely, only ten percent. That helps a little, in a situation where the troops need a lot of help.

Currently, the lightest load carried, the "fighting load" for situations where the troops were sneaking up on the enemy and might be involved in hand-to-hand combat, is 28.6 kg (63 pounds). The "approach march load", for when infantry were moving up to a position where they would shed some weight to achieve their "fighting load", is 46 kg (101 pounds). The heaviest load, 60 kg (132 pounds), was the emergency approach march load, where troops had to move through terrain too difficult for vehicles. As in the past, the troops often ignored the rules and regulations and dumped gear so they could move, or keep moving.

In Afghanistan the problem is made worse by the high altitudes (up to 5,000 meters) the troops often operate at. The researchers found that in Afghanistan, even though the infantry were in excellent physical shape, troops would sweat nearly 59 cl (20 ounces) of fluid an hour while marching at high altitudes in bright sunlight in moderate temperatures. That meant more weight in water had to be found to keep these guys going.

Until the 1980s, you could strip down (for actual fighting) to your helmet, weapon (assault rifle and knife), ammo (hanging from webbing on your chest, along with grenades), canteen and first aid kit on your belt, and your combat uniform. Total load was 13-14 kg (about 30 pounds). You could move freely and quickly like this, and you quickly found that speed and agility was a lifesaver in combat. But now the minimum load carried is twice as much (27 kg) and, worse yet, more restrictive.

While troops complained about the new protective vests they valued it in combat. The current generation of vests will stop rifle bullets, a first in the history of warfare. And this was after nearly a century of trying to develop protective vests that were worth the hassle of wearing. It wasn't until the 1980s that it was possible to make truly bullet proof vests using metallic inserts. But the inserts were heavy and so were the vests (about 11.3 kg/25 pounds). Great for SWAT teams, but not much use for the infantry. But in the 1990s, additional research produced lighter bullet proof ceramic materials. By 1999, the U.S. Army began distributing a 7.3 kg (16 pound) "Interceptor" vest that provided fragment and bullet protection. This, plus the 1.5 kg (3.3 pound) Kevlar helmet (available since the 1980s), gives the infantry the best combination of protection and mobility. And just in time.

Since the end of the Cold War more of the situations U.S. infantry find themselves in involve lightly armed irregulars who rely more on bullets than bombs. The bullet proof vest eliminates most of the damage done by the 30 percent of wounds that occur in the trunk (of which about 40 percent tend to be fatal without a vest). The Kevlar helmet is also virtually bulletproof but it doesn't cover all of the head (the face and part of the neck is still exposed). Even so, the reduction in deaths is significant. Some 15-20 percent of all wounds are in the head and about 45 percent of them are fatal without a helmet. The Kevlar helmet reduces the deaths by at least half and reduces many wounds to the status of bumps, sprains, and headaches. Half the wounds occur in the arms and legs, but only 5-10 percent of these are fatal and that won't change any time soon. Thus since Vietnam, improved body armor has reduced casualties by more than half. The protective vests used in Vietnam and late in the Korean war reduced casualties by about 25 percent since World War II, so the risk of getting killed or wounded has been cut in half since World War II because of improved body armor. Much better medical care (especially rapid evacuation of casualties by helicopter) has helped change the ratio of dead to wounded from 1:3 during World War II to 1:5 today.

The Interceptor vest was an improvement in other ways. It was easier to wear and was cooler in hot climates because you could more easily adjust it to let some air circulate. You could also hang gear from the vest, making it more a piece of clothing. It's still hot to wear the vest in hot weather but if you're expecting a firefight, it's easier to make the decision to wear the vest. You know it will stop bullets. U.S. troops who have fought in Afghanistan and been hit with rifle bullets that would have penetrated earlier vests are already spreading the word throughout the ground combat community. All you have to do is exercise in such a way that you are better able to carry the weight and still be mobile.

The army has instituted new training methods that emphasize building muscle and the ability to be agile under all that weight. That helps somewhat, but moving vigorously with all that weight has led to more musculoskeletal problems, many of them with long term consequences.  The enemy has also adapted, knowing that the more heavily encumbered Americans were not as agile or as fast and that could be exploited. The frustration of being slower than your foe often led U.S. troops to exertions that brought on musculoskeletal injuries. The new body armor may protect from bullets and shell fragments but it does nothing for over exuberant troops.