3 sentences for 结实 (jiē​shi — buff)

1. 他的手臂肌肉非常结实。

   tā de shǒu​bì jī​ròu fēi​cháng jiē​shi.

   The muscles in his arms are very firm.

   Source: Dong Chinese Dictionary

2. 他经常锻炼身体，肌肉长得很结实。

   tā jīng​cháng duàn​liàn shēn​tǐ, jī​ròu zhǎng de hěn jiē​shi.

   He exercises regularly, and his muscles are very well-built.

   Source: Dong Chinese Dictionary

3. 由于长期锻炼，他的腹部肌肉非常结实。

   yóu​yú cháng​qī duàn​liàn, tā de fù​bù jī​ròu fēi​cháng jiē​shi.

   His abdominal muscles are very firm due to long-term exercise.

   Source: Dong Chinese Dictionary