Oblivion:Athletics

Athletics is the skill that determines how quickly you run and swim.  As your level increases, your Fatigue regenerates progressively faster when running.

In-game Description: Run and swim faster, and regenerate lost fatigue faster.

Mastery
Mastery Perks
A Novice regenerates two Fatigue per second when running.
An Apprentice regenerates four Fatigue per second when running.
A Journeyman regenerates six Fatigue per second when running.
An Expert regenerates eight Fatigue per second when running.
A Master regenerates the full ten Fatigue per second, whether they run or not.

Skill Benefits
Your athletics skill level determines how quickly you run and swim; see Movement Formulas for details.

Skill Increases
Your athletics skill increases by 0.03 points for every second (real time) spent running, and 0.04 points for every second spent swimming.  (No athletics skill is gained if you are sneaking while running).

Because you gain athletics skill whenever your character runs, you will tend to constantly (but slowly) gain athletics skill.  One implication because of this is that it is very difficult to control athletics skill increases.  

Tricks to increase your athletics skill somewhat more artificially include:
Leave your character running against an obstacle for a long period of time.  PC users can just toggle the auto move feature (Q key by default).  Xbox 360 or PlayStation 3 users can tie a rubber band around the controller's left thumbstick so that the character runs constantly.
Swimming increases athletics faster than running. Try using a Water Breathing spell or enchantment, especially if you want to leave your character auto-swimming (using the same methods described as in the previous note). As Argonians have Water Breathing as a natural ability, no such spell or enchantment is necessary.

See also:
Increasing Skills: General tips on how to improve your skills semi-naturally.
Trainers: Pay for athletics lessons.
 
Skill Books: Books that provide lessons in athletics.
Increasing Attributes: Tips on training skills to improve the Speed attribute.
Free Skill Boosts: one free athletics skill boost (for three points) is available by completing the Origin of the Gray Prince quest; athletics bonuses are also available to Vampires.
Magic Items: There are multiple generic items with the fortify athletics enchantment.
Unique Items: A list of unique items, some of which fortify the athletics skill. These do not include Leveled Items such as those received from quests, or Artifacts.
:Unique items include:
::*Monkeypants is a pair of light greaves that can be obtained from Suurootan at Novaroma. Among other enchantments, the greaves fortify your athletics skill by 10 points.
::*Jewel of the Rumare is a ring awarded at the end of the quest Go Fish. It fortifies athletics by 4 points and also provides Water Breathing.
::*Nistor's Boots are a unique pair of boots that can be obtained from Elsynia at the Best Goods and Guarantees. Among other enchantments, the boots fortify your athletics skill by 5 points.

Dialogue
When your skill level reaches 70 or higher, people will start saying: "You're a fit one.  Been running a lot?"

Character Creation
The following races provide initial skill bonuses in athletics:
+5 bonus: Dunmer, Khajiit
+10 bonus: Argonian, Redguard

The following standard classes include athletics as a major skill:
Barbarian, Crusader, Monk, Nightblade, Rogue, Scout, Warrior, Witchhunter

Messages
The following table provides the messages that are displayed when your Athletics skill levels up.



Notes
Athletics is one of only two skills (the other is acrobatics) that can be meaningfully fortified above 100.  Increasing athletics past 100 continues to increase the character's run speed, up to a maximum value of 255.  On the other hand, athletics is not modified by your character's luck.
Once your combined Fame and Infamy reaches 10, you can visit the Jone heaven doomstone to receive the greater power ''Jone's Shadow''.  One of several benefits of this power is that it fortifies your athletics skill 30 points once a day for 120 seconds.