Xiǎng yào shǒubì xiàntiáo hǎokàn, sāntóujī de xùnliàn bùnéng shǎo.
If you want nice-looking arms, you can't skip triceps training.
Tips
usage
Common gym/anatomy companions: 二头肌 (èrtóujī, biceps), 胸肌 (xiōngjī, pecs), 背肌 (bèijī, back muscles), 腹肌 (fùjī, abs), 三角肌 (sānjiǎojī, deltoids). Gym splits like '练胸三' (chest + triceps) are stated this way.
memory
Literal: 'three-head muscle' — exactly the Latin meaning of 'triceps' (tri- 'three' + caput 'head'). The triceps has three heads of origin, hence the name in both languages.
