He is training his triceps brachii muscle every day.

He goes to the gym every day to train his triceps surae muscle.

The splenius capitis muscle is a part of the neck muscles, helping to tilt the head backwards.

The obliquus capitis superior muscle is part of the neck muscles, helping to tilt the head.

The obliquus capitis inferior muscle is a part of the neck muscles, helping to tilt the head.

The rectus capitis lateralis muscle is part of the neck muscles, and it helps to move the head sideways.

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

He is doing a special exercise to strengthen his temporoparietalis muscle.

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

I strained a muscle at the gym yesterday.