He is training his rectus abdominis muscle every day.

If you train your transverse abdominal muscle, your body balance will improve.

He is doing a special exercise to train his digastric muscle.

He never misses doing his gastrocnemius muscle stretches every day.

This area is rich in subterranean rivers, which serve as a source of groundwater.

He was surprised to hear the news.

My hometown is Fukui Prefecture.

The vice president performs the duties of the president in his absence.

In Japanese morphology, the inflected form plays an important role.

He suffers from adrenal cortex insufficiency.