The trapezius and deltoid muscles are part of the shoulder musculature. Lack of flexibility in these muscles can cause low back pain or neck pain. In addition, you may not be able to achieve your fitness goals if you ignore stretching these muscles. The deltoid is a three-headed muscle, so stretching only one segment of your deltoid muscle is not efficient enough to obtain optimum shoulder health. Hold each stretch for at least 30 seconds and do two sets. Ensure you warm up before you stretch.
Posterior and Medial Deltoid
Grab your upper arm on the side of the shoulder you want stretched and place it horizontally across your chest. Next, with your opposite hand, pull your upper arm so that you feel a slight stretch in the back of your shoulder. Do not grab your elbow. The most common mistake is to shrug your shoulders up while executing the stretch. Keep your shoulders down so you actually feel the stretch along your back as well. Hold for at least 30 seconds while breathing naturally. Repeat with the other arm.
This stretch can also be classified as a pectoral stretch, because it deeply lengthens your chest muscles. Stand next to a door frame or sturdy post. Position one straight arm slightly lower than your shoulder on the frame. Turn your body away from your arm until you feel a stretch in the front of your shoulder. Hold for at least 30 seconds and repeat on the other side.
For this stretch you can either sit or stand. Tilt your head slowly towards one side as if you are trying to have your ear contact your shoulder. Retract and depress the scapula on the side being stretched. Really relax the shoulders so that you can feel a deep stretch. Place the palm of your hand on top of your head as you pull your head slightly further to one shoulder. Repeat on other side.
Stretching should be performed every day to keep your muscles loose. This will reduce chance of injury and prepare your muscles for the next workout that you do. Stretching your deltoids and trapezius at the end of your shoulder workouts will help release lactic acid from those muscles. As a result you will have an increase in shoulder flexibility. As a reminder, do not stretch to the point of pain but rather to the point of tension.