He measured muscle activity using an electromyograph.

I examined muscle activity using an electromyogram.

This ancient proverb, 'know the other side and yourself, and you will not be in danger in a hundred battles', teaches us the importance of understanding ourselves and others.

He did a somersault in the park.

He goes to the gym every day to train his biceps brachii muscle.

He is doing squats to train his quadriceps femoris muscle.

He is doing squats to train his biceps femoris muscle.

He is training his triceps brachii muscle every day.

He is doing special exercises to strengthen the opponens digiti minimi muscle of his foot.

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