# bulk up

Source: https://englishreference.com/word/bulk-up
Updated: 2026-08-27

## Senses

### 1. to gain muscle

phrasal verb · CEFR B2 · Informal

to make your body bigger and stronger by lifting weights and eating more food.

For teachers: to increase one's body mass, specifically muscle tissue, through a combination of hypertrophy-focused resistance training and a caloric surplus.

- He spent the winter at the gym trying to bulk up for the rugby season.
- After months of consistent heavy lifting and a strict nutritional plan, the athlete managed to bulk up by nearly ten kilograms of lean mass.

Usage: Intransitive when referring to a person's physical growth.

## Examples

- He wants to bulk up before the rugby season starts.
- After months of lifting heavy weights and eating extra protein, the athlete managed to bulk up significantly.
- The actor was required to bulk up for his role as a superhero, undergoing a rigorous six-month physical transformation under professional supervision.

## Usage notes

- Teaching tip: contrast with 'slim down' or 'tone up'; 'bulk' implies a significant increase in size and volume rather than just definition.

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