Weight-reducing clothing is clothing that players can wear that will reduce their weight. There are currently fourteen items that can be worn to reduce a player's weight. If a player wore the pieces of armour that offered the maximum weight reduction (Gold athlete's hat, Agile top, Agile legs, Boots of lightness, Penance gloves, and Wicked cape), that player would achieve the lowest possible weight of –40.8 kilograms.
Weight-reducing armour is very useful in skills and quests that involve a lot of running because run energy decreases relative to a player's weight (e.g. lower weight means less run energy depleted). Agility obstacles also have a greater chance of being completed if the player is lighter. Other weightless items exist and can be used without penalising a player's weight.
On 22 June2009, extra weight-reducing equipment may be obtained from the advanced agility courses after completing a total of 250 'perfect' (i.e. without failing) laps.
On 19 January 2010, the weight of Penance gloves was changed from -4.5 kg to -7 kg.
On 24 July2012 the Gielinor Games went live and the Athletes sets was released. The bronze, silver and golden Atheletes set are all able to reduce weight when worn, being the bronze and silver sets the only weight-reducing equipment available for free to play. As the Gielinor Games event is over the suit cannot be obtained anymore.
The lowest weight achievable is -40.8kg, which is helpful for times when long periods of running are required, like Penguin hunts, and during some quests. In addition it can be useful for moving ores, logs, and other heavy items you need to move in large bundles (e.g. during All fired up (minigame)). If you have an experience boosting set it may be a better choice for experience.