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Isometric shoulder strengthening exercise into extension self

The image shows how to do Isometric shoulder strengthening exercise into extension self
Isometric shoulder strengthening exercise into extension self

To perform Isometric shoulder strengthening into extension self

  • Stand as shown with elbow bent as shown.
  • With back of other hand, support and hold elbow.
  • Push backwards with involved arm, not allowing supporting hand to move
  • Do not hold breath.
  • Maintain the contraction for few seconds and release.
  • Repeat for 10 times.

In shoulder extension the humerus is rotated out of the plane of the torso so that it points backwards (posteriorly).The muscles involved in this action are: latissimus dorsi and teres major, long head of triceps, posterior fibers of the deltoid.

Latissimus Dorsi

Action: Adducts and medially rotates humerus; extends the shoulder joint as in pulling on oars of a rowboat; produces back swing of arm in such actions as walking or bowling; with hands grasping overhead objects, pulls body forward and upward, as in climbing; produces strong down strokes of arm as in hammering and swimming (nicknamed the “swimmer’s muscle”); aids in deep inspiration, sudden expiration as in sneezing and coughing, and prolonged forceful expiration as in singing or playing a wind instrument.

Origin : Vertebrae T7–L5; lower three or four ribs; iliac crest; thoracolumbar fascia

Insertion : Floor of intertubercular sulcus of humerus

 

Teres Major: Extends and medially rotates humerus; contributes to arm swinging.

Origin  :Inferior angle of scapula

Insertion : Medial lip of intertubercular sulcus of humerus

 

Deltoid Muscle :

This thick muscle covers the shoulder protecting the joint. It assists in many movements of the arm, moving it forward, backward, and outward abduction.

It arises from two bones and three places: from the lateral third of the clavicle, from the acromion, and from the spine of the scapula. The fibers cover the shoulder joint to merge as a small tendon which inserts onto the deltoid tuberosity, a small projection on the lateral aspect of the shaft of the humerus, about midway down.


References:

https://en.wikipedia.org/wiki/Shoulder

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4495440/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4252758/