The rules for modern mixed martial arts competitions have changed significantly since the early days of vale tudo, Japanese shoot wrestling, and UFC 1, and even more from the historic style of pankration. As the knowledge of fighting techniques spread among fighters and spectators, it became clear that the original minimalist rule systems needed to be amended. The main motivations for these rule changes were protection of the health of the fighters, the desire to shed the perception of "barbarism and lawlessness", and to be recognized as a legitimate sport.
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.
Small, open-fingered gloves were introduced to protect fists, reduce the occurrence of cuts (and stoppages due to cuts) and encourage fighters to use their hands for striking to allow more captivating matches. Gloves were first made mandatory in Japan's Shooto promotion and were later adopted by the UFC as it developed into a regulated sport. Most professional fights have the fighters wear 4 oz gloves, whereas some jurisdictions require amateurs to wear a slightly heavier 6 oz glove for more protection for the hands and wrists.
Time limits were established to avoid long fights with little action where competitors conserved their strength. Matches without time limits also complicated the airing of live events. The time limits