筋肉 refers to muscle tissue in the body.
COMMON PATTERNS:
- 筋肉を鍛える (to train/build muscles)
- 筋肉がつく (to gain muscle)
- 筋肉が落ちる (to lose muscle)
COMPOUND WORDS:
- 筋肉痛 (muscle pain, DOMS)
- 筋肉質 (muscular build)
- 筋肉トレーニング (muscle training, weightlifting)
CASUAL TERM: