Grinding is a term used in video game culture, referring to the act of repeating an action or set of actions, including non-repetitive tasks to achieve a desired result at a level of certain difficulty, typically for an extended period of time, such as earning experience points, in-game loot and currency or to improve a character's stats. Grinding is commonly performed in MMORPGs. Synonyms for grinding includes treadmilling, which is a comparison with exercise treadmills, and less commonly pushing the bar. Related terms include farming, in which the repetition is undertaken in order to obtain items, relating the activity to tending a farm field. A player is commonly motivated to grind due to a player's desire to earn rewards, gather resources, or increase their level. Alternatively, some people may enjoy repetitive tasks for the purpose of relaxation, especially if the task has a consistently positive result. MMORPGs often require grinding, which is achieved through a progression system. These systems vary from game to game but tend to involve some form of point allocation. For some games, grinding is an integral part of the gameplay and is required if the player wants to make significant progress. In some cases, progression may be entirely negated if the player does not grind enough, for example an area necessary for the story may be locked until a certain action is repeated a certain amount of time to prove the experience of the player. Examples of games with grinding include: RuneScape requires the player to partake in repetitive tasks to level up skills. An example would be the "Slayer" skill, which requires players to defeat a certain number of a specific type of creature. The monsters are chosen based on the player's combat level. Players gain experience while fighting the monsters, which increases both their Slayer level and their combat skills. Because the effort is repetitive and time-consuming, it is considered "grinding". Borderlands 2 requires players to repeatedly kill specific enemies to acquire Legendary items.