Just How Important Are They? If you knew just how important your shoulder flexor muscles were for speed, then you’d probably invest a lot more time in training them. This is because your shoulder flexor muscles create much needed thrust to go along with the leg pushing off the ground helping you to run your very best. Meet the Shoulder Flexor Muscles. The shoulder flexors muscles, also known as the arm flexor muscles, consist of 4 muscles. Their names are 1) anterior deltoid, 2) pectoralis major, 3) biceps brachii and 4) coracobrachialis. See Figure 1 below: Figure 1. The Shoulder… read more
