Skills/strength
Official Description
Power reflects a soldier's physical strength. A high physical strength is especially important for soldiers who handle heavy weapons and armor, as well as soldiers who fight in close quarters. Power directly influences the damage a soldier can do in melee combat, and how well a soldier is able to handle a weapon's recoil. Recoil decreases accuracy, so a soldier using a weapon with a lot of recoil needs strength to keep it pointing in the right direction when firing.
Power also affects soldier's health points (HP) and the amount of equipment a soldier can carry before he becomes encumbered. An encumbered soldier suffers a time units (TU) penalty, as well as an accuracy penalty.
To gain one point of power skill your soldier needs to hit 8 enemies with any heavy weapon.