Deltoid Muscle Strain: Symptom & Treatment

The large Deltoid muscle (M Deltoideus) is a thick triangular muscle, emanating around the shoulder, covering the shoulder joint and forming the rounding of the shoulder. The muscle is fastened on the humerus. The various parts of the deltoid muscle take part in nearly all movements of the shoulder joint.  Muscle rupture occurs when a muscle is subjected to a load beyond the strength of the muscle for e.g. butterfly swimming, weight training, weight lifting. The deltoid muscle rupture can be located both in the front and the back as well as at the attachment to the upper arm (humerus).

Deltoid Muscle Strain

The muscle lifts the arm up sideways. The front part helps to lift the arm up forwards, known as shoulder flexion and the back part helps to lift the arm up backwards, known as shoulder extension.


A sudden pain in the muscle at the front of the shoulder is common. Pain is reproduced when lifting the arm from your side to the front keeping it straight against resistance. Or when you lift your arm from your side up sideways against resistance if the strain is in the mid portion or top of the muscle.

Tenderness and swelling where the muscle is torn may also be visible and for very severe injuriesbruising may develop.

A rotator cuff strain may have similar symptoms to a deltoid strain and is probably far more common so should always be considered.

Grade 1 deltoid strain


You might have tightness in the muscles. You may be able to use your arms properly or do press ups easily. You probably won’t have much swelling. Trying to lift your arm up sideways or to the front or back of the body probably won’t produce a lot of pain.


Apply ice for the first 24 hours (15 mins at a time) then heat. Light exercises – 4 sets of 10 repetitions 3 times a week (for example). Gradually build up the weight to strengthen the muscles. The athlete should ease down on training for a week or two but it is unlikely they need to stop unless they are getting pain. A doctor or sports therapist can use sports massage to speed up recovery as well as ultrasound or electrical stimulation.

Grade 2 deltoid strain


You probably cannot use your arm properly or do press ups. You may get occasional sudden twinges of pain during activity. You may notice swelling. Pressing in causes pain. Lifting your arm up to the front, side or back against resistance causes pain.


Ice for 3 to 5 days. See a sports injury specialist who can advise on rehabilitation. Apply heat (hot water bottle, hot baths, see a specialist for ultrasound). From day 7 do light, pain free exercises (4 sets of 10 reps three times a week). Cycling 2 to 3 times a week. Begin stretching (hold stretches for 30 secs, 5 times a day). From day 14 start to slowly get back into sports activities.

A doctor or sports therapist can use sports massage techniques to speed up recovery and advise on a rehabilitation program.

Deltoid Muscle Strain

Grade 3 deltoid strain


You will be unable move your arm and likely to be in severe pain. Bad swelling will appear immediately. Contracting the muscle will be painful and there may be a bulge or gap in the muscle. Expect to be out of competition for 3 to twelve weeks or more.


  • Week 1: Seek medical attention immediately. R.I.C.E. (Rest, Ice, Compress, Elevate.)
  • Week 2: Practice pain free static contractions ( if it hurts don’t do it). Heat with hot water bottle, hot bath or ultrasound.
  • Week 3: All of the above plus increase the intensity of static contractions 4 sets of 10 reps 3 times a week.
  • Week 4: Pain free exercises e.g. light lateral raises and rotator cuff exercises, 4 sets of 10 reps 3 times a week. Cycling 2 or 3 times a week. Start stretching exercises, hold for 30 secs, 5 times a day.
  • Week 5: Build up exercises, 4 sets of 6 to 8 reps 2 days a week. Gradually build up to sports specific exercises.

Massage by a doctor or sports therapist can speed up recovery as well as ultrasound or electrical stimulation. In some cases surgery is required.

If you suspect a grade two or three injury you must see a Sports Injury Specialist immediately.


The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

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