In 2001, Matt Larsen, then a Sergeant First Class, established the United States Army Combatives School at Fort Benning.
One of the fundamental aspects of US Modern Army Combatives training is the use of competitions as a tool to motivate Soldiers to train. Realizing the inherent problem with competitive systems, that competitors will focus their training on winning and therefore only train the techniques that are allowed in competition, Larsen designed a system of graduated rules that, combined with scenario based training, demand that Soldiers train on all aspects of fighting.
In this interesting video, an Army female fights a male under the intermediate rules:
Intermediate rules– Closed fist strikes to the body are allowed and open hand to the face. Kicks are allowed anywhere except to the groin while standing. Knee strikes are allowed to the body while standing and to the legs while on the ground (not to the head). Slamming from closed guard is allowed. Matches are 10 minute rounds.