Marathon


 * For the Call of Duty 4: Modern Warfare challenge, see Boot Camp (challenges).

Marathon is a tier 1 perk in Call of Duty: Modern Warfare 2 and a Tier 3 perk in Call of Duty: Black Ops.

Call of Duty: Modern Warfare 2
Marathon gives the user an infinite sprint duration, replacing the Extreme Conditioning perk. It is one of the first perks in Create a Class, unlocked at the start of the game.

Pro Version
The pro version of Marathon is unlocked after the player has sprinted 26 miles while it is equipped. The Pro version allows the user to go over cover and up ladders twice as fast, allowing for quick battlefield maneuvers. It should be noted that while players vault objects faster, their sprint speed on level ground is still the same.

Call of Duty: Black Ops
Marathon will return in Black Ops as a tier 3 perk. It only allows the player to sprint longer instead of unlimited sprint, which is similar to Extreme Conditioning from Call of Duty 4 and World at War. The Pro version of this perk grants no fall damage.

Call of Duty: Modern Warfare 2

 * The perk's picture and effect are very similar to the Extreme Conditioning perk from both Call of Duty 4 and Call of Duty: World at War.
 * The player needs to run 104 miles with this perk to complete the VI Challenge and unlock the Marathon Pro Emblem.
 * This perk, along with Lightweight and SitRep, are considered some of the hardest perks to achieve the VI Challenge for.

Miscellaneous

 * There is also a challenge in Call of Duty 4: Modern Warfare and Call of Duty: World at War called "Marathon," which is completed by sprinting the same distance of a real Marathon, 26 miles.