To better track PTSD (post-traumatic stress disorder) and other long term effects of combat (concussion, as well as muscle and skeletal problems), the U.S. Army began studying the medical records of millions of current, former and retired troops. After interviewing some of the older troops, it found that there was indeed more long term medical problems for those exposed to explosions during combat, and those who went through lots of strenuous military training. But the researchers also found long term health problems in unexpected areas. It was discovered, for example, that most helicopter pilots eventually develop back pain. Further examination revealed the cause. Helicopter pilots, despite working while sitting down, wear a lot more gear than most air force pilots, and work in a non-air conditioned environment, while often sitting forward and at an uncomfortable angle. Their seats, while appearing comfortable, are not as comfy as you might think, especially for a pilot wearing a protective vest and carrying lots of other emergency gear (in case the chopper goes down and a quick exit is required). Few pilots reported the back pain, which got worse with age.
Piloting helicopters only became a major military activity in the 1960s, and that first generation of pilots are now reaching the age where old sports injuries are becoming very uncomfortable. The army has found that the back pain for older helicopter pilots was not all sports related (although the early crop of chopper pilots tended to be athletes in school.) Now the army is learning a lot more about long term injuries, and the resulting chronic pain issues.
The army has been learning similar lessons since the 1970s, as a lot more women joined the military. Some of these lessons were learned via the experience of other nations and services. Unlike the U.S. Army, the British and the U.S. Marines decided that lower levels of physical fitness for women soldiers was not acceptable and, since 1998, the British women have had to meet the same high standards for physical fitness as the men. Since then, the army has learned the same thing the coaches of the increasingly popular women's sports program have; women are more prone to "overuse" injury. In some sports (like basketball) women have ten times the number of certain types of injuries (knees) as men. In the British army, even before the more vigorous training program for women, the percentage of male recruits lost because of "overuse injury" was 1.5 percent, versus 4.6 percent for women. The new training program, which does get the women in shape, also puts 11.1 percent of the recruits out of the service because of injuries. The basic problem is that less muscle mass and lower bone density puts 39 percent more stress on women during vigorous physical training. The army found that some of these injuries could be greatly reduced if the physical training for women was done over a six month period, rather than the current three month course men and women are using. But the injury rates will probably always be higher because of the fundamental gender differences.
All these discoveries will cost the military a lot of money, but it's best to be the first to announce the problem. Sports medicine in general has become more accurate and predictive, and a lot of late-life medical problems can be traced to seemingly healed injuries back when the victim was an adolescent or young adult. A lot of these injuries can be avoided by redesigning equipment, and limiting how much is worn when troops are in foot. Such limits are not always possible, so a lot of former infantrymen are going to qualify for treatment of injuries acquired when they were in their 20s and required to haul over 50 kg (110 pounds) of gear up and down mountains in Afghanistan. But for helicopter pilots, there may be better prospects for a solution, mainly through the development of a new seat.