Arm Pumping
Arm Pumping, also known as "shoulder pumping", can be used any time Samus is moving on foot. While moving on foot, the animation of Samus changing the position of her arm cannon will shift her forward one pixel. This includes angle up, angle down, and bringing the arm cannon forward (ex. firing a weapon).
Additionally, Samus bringing her arm cannon back to her side - or in the event the beam is being charged, back in front of her - will also count as an arm pump. This will be referred to as the "neutral position."
This technique is most commonly executed by spamming the shoulder buttons (R and L) as players almost always keep angle up and angle down mapped to those respective buttons.
The reason holding angle down while mashing angle up is less efficient for humans than mashing both angle down and angle up while trying to space them appropriately is illustrated in the input strings below. R means "angle up", L means "angle down", and "s" means "nothing." The bold portions indicate on which frames an arm pump would take place. These examples assume the player can mash each shoulder button at an average rate of six per second.
An example of what arm pumping would look like when mashing angle up while holding angle down:
R L L L L L L L L L L L R L L L L L L L L L L L R L L L L L L L L L L L R L L L L L L L L L L L R L L L L L L L L L L L R L L L L L L L L L L L R
An example of what arm pumping would look like when mashing both angle buttons with decent spacing:
R s s s L s s s s s R s s s s s L s s s R s s s s s s L s s s s R s s s s s s L s s R s s s s s s L s s s s R s s s L
As indicated above, because of the effect the neutral position has, it is more efficient for humans to mash both shoulder buttons and try spacing them appropriately rather than mashing angle up while holding angle down.
Because this technique, when performed a single time, causes a one pixel shift directly forward, it can cause Samus to fall off of certain slopes when moving forward. If this occurs, her momentum will be reset once she lands, resulting in a loss of speed, so be careful about arm pumping when moving on such slopes.
An example of a room which contains slopes that Samus cannot fall off of from arm pumping is Speed Booster Hall. An example of a room which contains slopes that Samus can fall off of from arm pumping is Parlor.
