bulk up

柯林斯词典

bulk up (bulking,bulked,bulks)

1. PHRASAL VERB If someone bulks up or if they bulk up their body, they put on weight in the form of extra muscle. 使變粗壯; 變粗壯
They feel I need to bulk up, and to improve my upper body strength. 他們覺得我需要變粗壯些，竝增強上身的力量。
My friend is obsessed with going to the gym and has really bulked up her arms. 我朋友迷上了去健身房，她確實把胳膊練得粗壯了。