The new rules included the introduction of weight classes; as knowledge about submissions spread, differences in weight had become a significant factor. There are nine different weight classes in the Unified Rules of Mixed Martial Arts. These nine weight classes include flyweight (up to 125 lb / 56.7 kg), bantamweight (up to 135 lb / 61.2 kg), featherweight (up to 145 lb / 65.8 kg), lightweight (up to 155 lb / 70.3 kg), welterweight (up to 170 lb / 77.1 kg), middleweight (up to 185 lb / 83.9 kg), light heavyweight (up to 205 lb / 93.0 kg), heavyweight (up to 265 lb / 120.2 kg), and super heavyweight with no upper weight limit.
Karate, especially Kyokushin and other full contact styles, has proven to be effective in the sport as it is one of the core foundations of kickboxing, and specializes in striking techniques. Various styles of karate are practiced by some MMA fighters, notably Chuck Liddell, Bas Rutten, Lyoto Machida, Stephen Thompson, John Makdessi, Uriah Hall, Ryan Jimmo, Georges St-Pierre, Kyoji Horiguchi, and Louis Gaudinot. Liddell is known to have an extensive striking background in Kenpō with Fabio Martella whereas Lyoto Machida practices Shotokan Ryu, and St-Pierre practices Kyokushin.
Marsden also adds that this type of bodyweight circuit is inherently flexible, so feel free to mix up the exercises as you wish. He just has one word of caution: "Feel free to change up the movements, but be cognizant of varying the exercises to maximize heart rate changes," he says. "By this I mean don't do three high-intensity movements before ending with two rounds of lower-intensity planks and flutter kicks." Rather, switch back and forth between higher- and lower-intensity exercises when planning your bodyweight circuit.
Mixed martial arts promotions typically require that male fighters wear shorts in addition to being barechested, thus precluding the use of gi or fighting kimono to inhibit or assist submission holds. Male fighters are required by most athletic commissions to wear groin protectors underneath their trunks. Female fighters wear short shorts and sports bras or other similarly snug-fitting tops. Both male and female fighters are required to wear a mouthguard.