I strained a muscle at the gym yesterday.

The semispinalis thoracis muscle is a deep muscle in the back that supports movement from the neck to the waist.

He is suffering from muscle pain in his semispinalis muscle.

He is doing special exercises to strengthen his spinalis muscle.

He exercises every day to strengthen his psoas muscle.

He exercises his pectoral muscles every day.

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

The semispinalis cervicis muscle is a part of the neck muscles, helping to pull the head back.

He started a special exercise to train his infraspinatus muscle.

He is doing special exercises to strengthen his supraspinatus muscle.