High Gravity
On high-gravity worlds, characters are burdened by their increased weight, and their physical abilities are affected accordingly. On a high-gravity world, where the gravity is at least twice as strong as standard gravity, a character (and her gear) weighs twice as much as on a standard-gravity world, but she has the same amount of strength. Such characters move at half speed, can jump only half as high or as far, and can lift only half as much. Thrown weapons (though not those of natives) have their ranges cut in half as they fall to the ground more rapidly. Modifications to running, jumping, and lifting can be negated by certain magic or technology, but projectiles remain affected. Characters who remain in a high-gravity environment for long periods (more than a day) often become fatigued and remain so until they leave the planet or become accustomed to the gravity.
Source
Core Rulebook pg. 402