Despite some detractors (which will be given their say in a subsequent piece) CrossFit's growth across the U.S. military and around the world is undeniable. But simply joining a CrossFit "box" to improve overall fitness is much different than adding CrossFit classes at a military fitness facility. It's not another Pilates or step class, and it takes some consideration.

Created in the mid-1990s, CrossFit is a branded fitness program that is "broad, general and inclusive" including a whole host of exercises and workouts. It's been a staple of fitness fans and professionals whose everyday occupations demand it, such as police officers and martial arts practitioners.

It has taken on particular meaning for military personnel. In 2010, the Army Command and General Staff College at Fort Leavenworth, Kan., commissioned a study testing the efficacy of CrossFit to improve soldier fitness. Over six weeks the 14 athletes in the study averaged a 20 percent increase in physical fitness level, with one participant increasing fitness level by 41 percent.

The study also noted the growing interest in CrossFit among military personnel, with more than 58 nonprofit military CrossFit affiliates in place at the time. That number continues to grow.

But adding CrossFit to a military facility requires some thought as well as cooperation among patrons, staff and CrossFit professionals. Army Maj. James Uptgraft, one of the study's authors and an operations officer for the 3rd Brigade Combat Team, 101st Airborne Division, is quick to recommend some focus areas when kicking off a CrossFit program:

1. CrossFit instructors must be well trained and certified.

"I think that there are two things that cause injuries with people who begin CrossFit: It's bad trainers and it's big egos," Uptgraft says.

Mark Tolmachoff, an instructor at the Command and General Staff College who oversaw the Army study, agrees, noting that certified instructors are the cornerstones to a solid program.

"There's a level of knowledge and expertise [and] they're kind of like the watchdogs," he says. "And when you get that core group of people who are certified and interested, they tend to generate interest from others."

Army Maj. Andy Morrison, coordinator for Iron Major CrossFit, the nonprofit affiliate for the Fort Leavenworth community, says the best athletes are not always the best instructors, however.

"It ultimately comes down to their mindset and their approach to their role as trainers," he says. "They have to be disciplined in their approach; they have to understand the needs of the athlete, and they have to commit to that layered approach of teaching techniques first, then consistency, and only then kind of gradually layering on the intensity."

2. Good relationships - among CrossFit participants, facility personnel and base leadership

"Especially on post … you've got to have some advocacy, and you've got to find the champion that can kind of help you get inroads into where you want to go," Morrison says. "Here, we have some senior leaders that have some experience with it and have a very positive outlook."

3. Emphasize communication among facility personnel, trainers and participants.

"What you're doing is potentially disruptive," Morrison says of bringing CrossFit to a facility. "So you've just got to try and understand why they might want to say 'no' - why you might encounter resistance - and then try and think through some solutions and proposals to overcome that."

Morrison also says there are detractors vocally opposed to CrossFit who cite higher injury risks among participants. But he says quality trainers are what make a difference. "And they need experience-doing it both as athletes and also as coaches and trainers," he says.

While Morrison notes that CrossFit doesn't require a lot of specialized equipment, he emphasizes the importance of a separate space to conduct CrossFit, if at all possible.

Tolmachoff says it was the combination of leadership support and an overwhelming response that led to a separate CrossFit facility at Fort Leavenworth.

Study author Uptgraft adds that military personnel are already programmed a certain way, so CrossFit is a great workout option. But facilities, he says, shouldn't only look at military personnel, but their spouses and other family members as potential for growth.

"I look back at the last six years I've been doing CrossFit [in the military], and the people that I've introduced to it," he says, "I've seen it … it's been life changing for some of these people, and it's been really fun to watch."