He is doing special exercises to strengthen his flexor digitorum superficialis.

He is doing special exercises to strengthen his flexor digitorum profundus.

He stretches his flexors every day.

He works at the blacksmith's every day to forge his skills.

This festival is held every year.

My flexor pollicis brevis hurts.

He is doing special exercises to strengthen his flexor pollicis longus.

This river is very shallow.

This river is very shallow.

I strained a muscle at the gym yesterday.