(bulge of one's) biceps
zeal; effort; enthusiasm
to put a lot of effort (into); to take a strong interest (in); to put great emp…
腕に力瘤ができている。
I have bulging biceps on my arms.
力瘤を見せて自慢した。
He showed off his biceps boasting.
力瘤が大きくなってきた。
My biceps have been getting bigger.