Run energy (sometimes called Stamina or Run) is a player's ability to run rather than walk around the landscape, and is measured as a percentage. Players all run at the same rate, unless their energy is at 0%, in which case they cannot run at all. Running is exactly twice as fast as walking. A player running covers 20 squares per 6 seconds, while a player walking covers 10 squares per 6 seconds. Energy gradually depletes whilst the player is running, and recovers whilst they are not.
The energy level is displayed in the game's options screen and is displayed (along with the World Map, compass and the Home Teleport) on the top-right hand corner of the minimap. These values show how much longer a player can run. Players can switch this option on to run everywhere they go, or they can run to one particular destination by holding down Ctrl when they click to move (see Game controls). Free players and players with Agility level of 1, have a recovery rate of 0.45 energy per second.
Each Agility level above 1 that a player has seems to reduce the time required to regenerate energy back to 100% by 1 second. For example, a player with 70 Agility can fully regenerate run energy to 100% after about 1 minute 47 seconds while a player with 90 Agility can fully regenerate to 100% in 1 minute 27 seconds.
Clicking rest will allow the player to sit down and recover run energy at a much faster rate (2.8 energy per second instead of 0.45 for level 1 Agility).
A player running, depleting energy.
Energy starts at 100% by default, but decreases as the player runs around. The rate at which it goes down increases with the weight of the items they are carrying (i.e. items in the inventory and any items they are wearing or have equipped). The rate at which energy decreases by running can be improved by having a negative weight (by wearing weight-reducing equipment such as the boots of lightness) instead of 0 kg.