Strength

Strength score is the major descriptor for the general athletic abilities of a character. High strength represents creatures whom can perform many great physical feats like lifting heavy boulders, pulling packed carts or cleanly cleaving an ogre's head off. Low strength represents creatures who lack muscle and bodily power to act effectively in the world with phyisical means, lacking the ability to move quickly, trading successful blows in a fisticuffs or carrying heavy objects.

Attack Rolls and Damage

You add your Strength modifier to your attack roll and your damage roll when making a cleaving, splitting or bludgeoning attack, or when you roll the damage for thrown attacks.

Movement Speed

Characters and monsters have a base speed (walking) represented by intrinsic capabilities. This is then individually modified by individual statistics, like strength or athletic proficiency. This is called modified speed. They can use as much or as little of their modified speed on their turn. You can read more about this in the Movement Speed section.

Carrying Capacity

Carrying capacity determines the amount of weight you can carry. Carrying capacity increases exponentially with your Strength score, making strength more impactful, both as a penalty for low strength and a bonus for high strength.

Carrying Capacity = your Strength score2 + your Brawn Proficiency bonus2 + (your Strength score + your Brawn Proficiency bonus)your Strength score / 10

Encumbrance

Encumbrance comes in stages, affecting both movement speed as well as defensive capabilities. When you carry weight in excess of X your carrying capacity:

EXCEEDING (X) EFFECT 1/3 of You are Encumbered. Your speed is reduced by 1/3. 2/3 of You are Heavily Encumbered. Your speed is reduced by 1/2. You have disadvantage on ability checks, attack rolls, and saving throws that use Strength, Dexterity, or Constitution. Equal to You are Extremely Encumbered. Your speed is reduced by 2/3. In addition to previous effects, you are unable to use any movement actions. 3/2 of You are Over Encumbered. Your speed is reduced to 0. In addition to previous effects, you must succeed on a Strength (Brawn) check of DC 10 + X for each 1/10 over your carrying capacity each turn. On a failure, you either drop the object or objects you're holding if you can, or get crushed and knocked prone by it, taking damage determined by what's appropriate by the DM. Encumbrance STATE SPEED EFFECTS Encumbered 2/3 - Heavily Encumbered 1/2 Disadvantage with STR, DEX, and CON. Extremely Encumbered 1/3 No movement actions. Over Encumbered 0 DC Strength check or proned.