Encumbrance

Your encumbrance is the total weight you are carrying. Encumbrance reduces your movement rate. It also makes swimming and climbing much more difficult, and travel (p. 23) slower.
A strong person can carry more than a weak one; Encumbrance is calculated as follows:

Encumbrance Level Weight Limit Movement Penalty
No Encumbrance 2×ST None
Light Encumbrance 4×ST -1
Medium Encumbrance 6×ST -2
Heavy Encumbrance 12×ST -3
Extra-Heavy Encumbrance 20×ST -4
Notes: