He is doing special exercises to strengthen his external obturator muscle.

The external anal sphincter plays a crucial role in helping us control defecation.

The external urethral sphincter is an important muscle for controlling the excretion of urine.

This sentence contains kanji not approved for regular use.

This sentence contains non-Jōyō kanji.

I have been to Outer Mongolia.

He engaged in an extravehicular activity from the spaceship.

He is undergoing training for extravehicular activity.

He is a foreigner, but he can speak Japanese fluently.

If you train your external oblique muscles, your waist will become tighter.