At the end of particularly long and arduous marches, the trainees will be set to performing more military chores, like planning an attack, or stalking another group of troops, trying to get close enough so that you could, if this were the real thing, kill them with a knife, bare hands or silencer equipped pistol. At every stage of this increasingly grueling training, some trainees are expected to drop out from exhaustion or because they decide this is a bit more than they are ready for. The training also involves use of weapons and live ammunition. This can get particularly scary, as the trainees out there using real bullets may have had only a few hours of sleep in the last few days and just completed a high speed 40 mile march. The danger is intentionally real, and meant to determine who has the ability to perform effectively under extreme conditions. Most final tests are administered after the trainees have been exhausted in one way or another. This is realistic, as combat missions often involve staying awake for long periods, and then carrying out a difficult combat mission.
A final exam will often consist of things like being sent off into the wilderness for a week or so with only a knife and some matches. This will sometimes be enhanced by sending training staff out to try and find the trainees. Anyone found, fails the course. You can tell a lot about how elite a force by how high their washout rate is. This usually varies from 20-80 (or more) percent. A higher washout rate rejects a lot of excellent warriors, but leaves you with a truly elite group.
Usually, elite forces recruit from existing military units. This provides a form of pre-screening, making sure that the trainees already have some level of familiarity with military matters. When volunteers are sometimes accepted directly from civilian life, you dont have the ability to see how the trainee will deal with being in the military for an extended period (like a year or more.) The stress testing for these men has to be different, because they lack many basic military skills. Still, it can work, and sometimes it is necessary if their aren't enough suitable candidates in the military. The U.S. Special Forces began doing this after September 11, 2001 because they wanted to expand and they needed a larger pool of talents to choose from.
One of the advantages of commando training is that it forces every man to be a leader. All commandos must be prepared to think for themselves and take over in stressful situations where the usual leaders are out of action or elsewhere. This has provided a bonus for nations with commando units, as those men who do not make a career of it go off to non-commando units with excellent leadership training. Even those who wash out of the commando training retain a more accurate appreciation of their capabilities under high stress situations. Those who serve as career commandos often get injured, or become too old to keep up, and leave commando units. Such men have leadership skills that are valued in any unit they end up in.
During World War II, these training methods were somewhat theoretical. Many senior commanders feared that commando units would drain other units of their best men and leaders. This did not prove to be the case. Many of the men who made the grade as commandos needed that kind of extreme challenge to really get motivated. These guys were often tagged as "troublemakers" in their mainline combat units. Moreover, the most elite commandos work in small groups, and this also attracts a certain type of individual who prefers to work alone or in small groups. The generals, while impressed with what commandos could do, took several decades before they realized what the other benefits were. After half a century, the unique commando training methods have proved to be something that works.
Survival of the Deadliest- Recruiting commando quality troops is a difficult process. But over the last sixty years, a particularly effective method has been developed. It all has to do with training that takes men to the edge, and a little beyond. One of the unheralded military developments during World War II was training methods that can detect, and enhance those soldiers who can reliably operate in extreme situations. These initial commando training courses can last from a few weeks to a few months and are meant to evaluate a candidates psychological, as well as physical, stamina. The training method consists of many of the usual military tasks, but performed to a higher standard and much greater intensity. Typical activities would be frequent long marches with heavy load, lots of physical training, and lots of running. Added to this is decreasing time for sleep.