Jumping is deliberate leaping — across a gap, over an obstacle, up at a ledge just out of reach — and the distance covered is read straight off a Jumping Success Value test.
Horizontally, a character clears a number of feet equal to the Success Value plus five. Every five feet of run-up taken in the same turn adds a foot, up to the bonus a full Move could supply.
Vertically, a character reaches up with one hand to their own height plus half the Success Value in feet, fractions retained. Actually catching hold of what is up there may call for a Dexterity test of its own.
Whatever distance is jumped counts against the character’s movement for the turn. A Critical Failure trips the character before they leave the ground and forces a Stumble Test; any success lets the leap happen, and the Success Value is then read as usual.
Jumping is also one of the two skills — Acrobatics being the other — that decide how well a fall is taken, and a purposeful leap is treated far more kindly than an unexpected drop.