腹筋

sit ups

I do sit ups for 3 sets of 30 reps each.

repetition　/,repə'tɪʃn/　n)繰り返すこと

abdominal muscle (abs)

abdominal   /æb'dɒmɪnl/　/æb'dɑːmɪnl/　adj)腹の

abdominal pain 腹痛

muscle　/'mʌsl/　n)筋肉