Mark S., a 27-year-old male, is complaining of left shoulder weakness. Mark trains with weights regularly (3-4 times each week) and has done this for 10 years. Six months ago, while doing the bench ...

Your pectoralis major is a large and powerful chest muscle that’s shaped like a fan. It starts from two sections: your breastbone (sternum) and your collarbone (clavicle). The two sections come ...