Stamina

The Stamina Gauge is a feature introduced in Skyward Sword.

Overview
The Stamina is displayed as a pie-shaped indicator that appears near Link whenever he is performing an action that requires great effort, such as climbing, sprinting, rolling, pushing, pulling, or carrying heavy objects, and performing a Spin Attack. Performing said actions depletes the Stamina Gauge, although some actions drain the meter faster than others: while dashing diminishes the stamina constantly, the Spin Attack decreases it in large portions.

When Link's stamina is depleted, Link will become tired and his movement will be slowed down dramatically for a few seconds until it replenishes. During this time, Link will also be unable to use items, including his sword and shield, leaving him defenseless against enemies. The Stamina Meter replenishes over time once Link stops performing strenuous actions, and it replenishes faster by standing still than by walking. Even if Link does not have the required stamina for a roll or spin attack, he can still perform one, making for perfect last minute bursts of speed as the stamina meter runs out before reaching something such as a Stamina Fruit to refill the meter. If Link buys a Stamina Potion in the Bazaar, he may half the rate that his Stamina Guage depletes for three minutes, or, if it is upgraded, the Stamina Gauge will not decrease at all for three minutes.

Link's Stamina gauge, upon reaching its last 1/4th, will drain at half speed for continuous actions such as running and climbing, but actions that drain Link's bar in portions (such as spin attacks and rolls) will have no change in the amount they drain. Because the stamina meter refills at a constant rate regardless of this, it is a common speedrunning tactic to allow the meter to refill up to 1/4th before running again, as this effectively doubles the refill rate.

While on Skipper's boat, sailing the Lanayru Sand Sea, the motor's constraints appear identical to the Stamina gauge, though it is shown in the shape of a boat's steering wheel. However, it acts exactly the same, the only differences being that the boat's motor depletes half as quickly as Link's stamina meter (and therefore depletes at a quarter of the speed when it reaches its last 1/4th of energy), and that the boat does not have any available actions that lower its meter in portions.

Trivia

 * The stamina meter is near identical in execution to the game's Oxygen Gauge or "Air Meter".