Shoulder Strain and Sprain

Anatomy of shoulder strains and sprains

Before jumping into the anatomy of shoulder strains/sprains, it is important to discuss the difference between them. Simply, a sprain is an injury to a ligament, and a strain is an injury to a muscle. The most common shoulder injuries are rotator cuff strains, pectoralis muscle strains, lat muscle strains, AC joint sprains, and glenohumeral ligament sprains.¹ 

Shoulder Strains

The rotator cuff, the pectoralis major, and the latissimus dorsi muscles are commonly strained or torn muscles.

Rotator cuff

Rotator cuff injuries are the most common shoulder strain, accounting for 12% of all shoulder injuries.² The rotator cuff comprises four muscles: the supraspinatus, infraspinatus, teres minor, and subscapularis. The supraspinatus functions to abduct or raise the arm from the side and attaches from the top of the shoulder blade to the top side of the humerus (arm bone). The infraspinatus and teres minor function the rotate the shoulder outward and attach from the back side of the shoulder blade to the side of the top portion of the humerus. The subscapularis functions to rotate the shoulder inward. It attaches from the front portion of the shoulder blade to the inside and upper portion of the humerus.³

If severe enough, an injury to the rotator cuff will require surgery. Discussion on rotator cuff surgery can be found on our Shoulder Repair Surgeries: Rotator Cuff and Labrum page. This page will focus on non-surgical rotator cuff injuries. 

Pec major

The pectoralis major (pec) is a massive muscle with many functions and is highly involved in blocking and tackling motions.  The pec’s primary job is to press the arm forward (like a bench press) and bring the arm across the body (like squeezing a ball carrier while making a tackle).  

Lat muscle

The latissimus dorsi (lat) is another massive muscle. It helps extend the shoulder, which is the movement in the backward portion of a bowling throw. It also rotates the shoulder inward and brings the arm toward the body, similarly to pec major.^3. Like other tissue injuries, shoulder strains can be graded to help classify the severity of the injury.

• Grade I (Mild strain):
• Minor overstretching or microscopic tearing of muscle or tendon fibers
• Mild discomfort with overhead motion or resisted shoulder movement
• No loss of strength or visible swelling
• Athletes often continue activity with minimal limitation
• Return to play: typically 0–2 weeks

• Grade II (Moderate strain or partial tear):
• Partial tearing of muscle or tendon fibers
• Local pain and tenderness, especially with resisted movements (e.g., raising or rotating the arm)
• Possible swelling or mild bruising around the shoulder girdle (shoulder swelling is rare)
• Functional strength deficits and pain with lifting or throwing
• Return to play: typically 2–6 weeks, depending on which muscle group is involved and position demands

• Grade III (Severe strain or complete tear):
• Full-thickness tear of muscle or tendon
• Sudden onset of pain, often with a popping or tearing sensation
• Visible deformity or contour change may be present (e.g., deltoid sag or supraspinatus atrophy occurs over time)
• Marked weakness and loss of function; the athlete often cannot lift the arm overhead
• May require surgical repair, especially in high-demand athletes
• Return to play: typically 8+ weeks, or 5–6 months if surgery is performed

Shoulder sprains

Shoulder sprains are incredibly common and generally occur to the anterior or posterior (front or back) ligaments of the shoulder. These ligaments attach from the front and back of the humerus to the front and back of the scapula. They all work together to prevent the humerus bone from dislocating. There are three different ligaments in the front of the shoulder that stabilize throughout different degrees of shoulder motion.

The superior glenohumeral ligament is most taught when the arm is in neutral and limits outward rotation and translation of the head of the humerus downward. The middle glenohumeral ligament is most taught at 45 degrees of shoulder elevation and prevents outward rotation and translation of the humeral head forward. The lower glenohumeral ligament has portions on the front and back of the shoulder. The front portion is most taught at 90 degrees of shoulder elevation. It limits outward rotation and translation of the humeral head up and forward, making it most at risk for injury when a quarterback is throwing. Conversely, the posterior portion helps prevent inward rotation and backward translation of the humeral head.

Another commonly torn ligament is the acromioclavicular or AC ligament, which attaches the acromion of the scapula to the clavicle (collarbone).³ In fact, the AC joint is the most common shoulder injury in football players, accounting for 41% of all shoulder injuries.² More information on AC joint injuries can be found on our AC joint injury page. 

Shoulder instability is a condition that can occur when the shoulder ligaments (as well as other tissues) are too loose and struggle to stabilize the arm in the shoulder socket properly. Instability typically occurs following trauma to the ligaments, muscles, or even labrum, but can also occur naturally. There are two types of instability, anterior and posterior, with anterior occurring in 20% of all shoulder injuries and posterior occurring in 4% of injuries.² Like other tissues, shoulder sprains can be graded to help classify the severity of the injury.

• Grade I (Mild sprain):
• Microscopic stretching of ligament fibers without structural disruption
• Mild tenderness around the joint, but no instability
• Minimal to no swelling or bruising
• Full strength and range of motion are typically preserved with slight discomfort
• Return to play: typically 1–2 weeks

• Grade II (Partial tear):
• Partial tearing of ligament fibers
• Localized pain with movement or palpation
• Possible joint laxity, especially with end-range motion
• Mild to moderate swelling; may have limited active overhead motion or push strength
• Return to play: typically 2–6 weeks, depending on position demands and degree of instability

• Grade III (Complete tear):
• Full rupture of the ligament, often resulting in joint instability
• Significant pain, swelling, and dysfunction
• Visible deformity may be present depending on the ligament (e.g., AC joint elevation)
• Functional limitations in pushing, lifting, and contact scenarios
• Surgery may be indicated in high-grade or recurrent instability cases
• Return to play: 6+ weeks, or 5–6 months if surgical repair is required

Cause of shoulder sprains and strains

Rotator cuff

There are multiple causes for rotator cuff injuries, including overuse, impingement, or direct impact. 47% of rotator cuff injuries are reported to be simple contusions, which occur from direct impact.¹ In football, rotator cuff tears are typically due to forceful contact. This can happen when a player lands hard on their hands from a dive, their arm gets caught under their body when landing or being tackled, or can even be a quarterback’s arm being restrained while attempting to throw.  

Pec major injury

The main cause of injury is forcing the arm away from the body against resistance.¹ This most commonly occurs when a player has their tackle broken as they are trying to wrap up, and is less likely to occur in fantasy-relevant players. 

Ligament sprains

Ligament injury occurs from direct or indirect trauma to the shoulder. Based on the ligament anatomy, we can infer the different angles of the shoulder that put each glenohumeral ligament at most risk for tearing. When a force causes the upper part of the arm to move forward relative to the rest of the arm, a sprain of these ligaments can occur. This type of force is often seen when a player reaches out to make a catch and is hit in the shoulder from behind. This can also occur when a quarterback is winding up to throw and is hit in the shoulder from behind. 

As mentioned above, a consequence of ligament injury (as well as injury to other tissues) can be the development of instability within the shoulder joint. Depending on the tissues injured, this instability can occur either anteriorly (to the front, most common) or posteriorly (to the back) and is often seen as a dislocation.

AC joint sprain

For information on the cause of an AC joint sprain, see our AC joint page.

Shoulder strain and sprain rehab process

Although strains/sprains are different in that they are injuries to different tissue types, they have very similar rehabilitation processes. Rehabilitation for muscle strains depends mainly on the grade of the injury. However, most rehab protocols follow a common pattern unless the strain/sprain was a grade 3 that required surgery, which would then have a surgical rehab protocol specified by the surgeon. 

Acutely, the injury is treated with ice, anti-inflammatories, manual therapy, electric stimulation, and other pain-relieving modalities, and a period of immobilization depending on the severity of the sprain/strain.⁷ Also, within the early phase of rehab will be the restoration of normal range of motion (ROM), which will start with passive range of motion (PROM) and progress to active (AROM).

Decreasing pain is the most important step here because it will allow the athlete to progress quickly to later phases, which involve more strengthening and sport-specific exercises.⁷ Dry needling can also decrease pain, increase range of motion, and improve function. Later in the early phase, neuromuscular electrical stimulation (NMES) can be used to improve motor coordination of the rotator cuff. Pain-free isometric exercises are also important to begin the neuromuscular re-education process, which precedes higher-level strengthening exercises.

During the intermediate phase, strengthening is progressed to include rotator cuff and scapular strengthening. Blood flow restriction (BFR) can also be beneficial for increasing strength because BFR requires less weight for the same strength gains, though proper training and supervision with BFR is advised.⁷ Cervical and thoracic mobility are also important due to the interaction between the scapula and the thoracic spine/rib cage.

The late stage of rehab continues to progress strength, as mentioned above. It also incorporates more dynamic stabilization exercises, plyometrics, and sport-specific drills.⁷ Finally, the player will be able to initiate contact drills, starting with position-specific drills, then unit drills, then full participation.⁷ Another critical role of all stages is to address issues that may have contributed to the injury in the first place, such as improving technique, altering mechanics, or improving range of motion in other areas.

Phases of Rehab	Treatments	Criteria to Enter Phase
Early Phase	Ice, NSAIDs, immobilization, pain-relieving modalities (electric stimulation) PROM, AAROM, AROM. Isometric strengthening. Manual therapy, dry needling. NMES.	N/A
Intermediate Phase	Progress strength for RTC and scapular muscles. Blood flow restriction (with proper training and supervision). Postural retraining Thoracic and cervical ROM exercises.	Pain-free ROM
Sports-Specific Phase	Continue strength exercises for RTC and scapular musculature. Incorporate dynamic stabilization drills. Plyometrics. Sport-specific activities, progress to contact drills.	Full and pain-free strength and ROM

References

1. Gibbs DB, Lynch TS, Nuber ED, Nuber GW. Common Shoulder Injuries in American Football Athletes. Curr Sports Med Rep. 2015;14(5):413-419.
2. Kaplan LD, Flanigan DC, Norwig J, Jost P, Bradley J. Prevalence and Variance of Shoulder Injuries in Elite Collegiate Football Players. Am. J. Sports Med. 2005;33(8):1142-1146.
3. O’Reilly, N. Shoulder. Physiopedia. Retrieved June 22, 2022, from https://www.physio-pedia.com/Shoulder 
4. Kary JM. Diagnosis and management of quadriceps strains and contusions. Curr Rev Musculoskelet Med. 2010;3(1-4):26-31. Published 2010 Jul 30.
5. Mulcahey, M. (2020, June). Sprains, strains and other soft-tissue injuries – orthoinfo – aaos. OrthoInfo. Retrieved June 22, 2022, from https://orthoinfo.aaos.org/en/diseases–conditions/sprains-strains-and-other-soft-tissue-injuries/
6. Kelly BT, Barnes RP, Powell JW, Warren RF. Shoulder Injuries to Quarterbacks in the National Football League. Am. J. Sports Med. 2004;32(2):328-331.
7. Weiss LJ, Wang D, Hendel M, Buzzerio P, Rodeo SA. Management of Rotator Cuff Injuries in the Elite Athlete. Curr Rev Musculoskelet Med. 2018;11(1):102-112.