What Causes Shoulder Popping During Workouts? 8 Reasons Explained

When you're in the middle of a workout and hear your shoulder pop, crack, or snap, it can be alarming. However, these noises are quite common and don't necessarily indicate something is wrong. Understanding why your shoulder makes these sounds can help you determine if it's a benign issue or something that requires attention. In this article, we’ll explore eight possible reasons your shoulder might pop or crack during workouts.

1. Cavitation: The Release of Gas Bubbles

One of the most common reasons for popping sounds in the shoulder is cavitation. This occurs when gas bubbles form and collapse within the synovial fluid of your joints. Synovial fluid is a lubricant that helps your joints move smoothly. When you move your shoulder, pressure changes within the joint can cause these gas bubbles to burst, leading to a popping or cracking sound.

Is it a cause for concern? In most cases, cavitation is harmless. It's the same phenomenon that happens when you crack your knuckles. However, if the popping is accompanied by pain, it could be a sign of an underlying issue that needs to be addressed.

References:

healthline.com/health/why-do-my-joints-pop

2. Tendon Movement: Snapping Tendon Syndrome

Another possible reason for shoulder popping during workouts is tendon movement. This phenomenon is known as snapping tendon syndrome. Tendons are fibrous tissues that connect muscles to bones. In the shoulder, tendons may snap over bony structures or other tissues during certain movements, producing a popping or cracking sound.

Common Tendons Involved:

Biceps tendon: The tendon of the biceps muscle can snap over the head of the humerus (upper arm bone).

Rotator cuff tendons: These tendons, which stabilize the shoulder, can also produce a snapping sound when they move over bony structures.

Is it a cause for concern? Snapping tendon syndrome is generally not painful and may not require treatment. However, if the snapping is frequent or associated with discomfort, it’s advisable to consult a healthcare professional for further evaluation.

References:

orthoinfo.aaos.org/en/diseases--conditions/snapping-scapula-syndrome

3. Labral Tears: Damage to the Shoulder’s Cartilage

The labrum is a ring of cartilage that surrounds the shoulder socket (glenoid) and helps stabilize the joint. A tear in the labrum can lead to a sensation of popping or catching in the shoulder, especially during overhead or rotational movements.

Types of Labral Tears:

SLAP tear: A tear at the top of the labrum where the biceps tendon attaches.

Bankart lesion: A tear in the lower part of the labrum, common in shoulder dislocations.

Symptoms to Watch For:

Pain in the shoulder, especially during specific movements

A sense of instability or the shoulder "giving way"

Loss of strength or a reduced range of motion

Is it a cause for concern? Labral tears can range from mild to severe. If you experience persistent shoulder popping along with pain or instability, it's essential to seek medical evaluation. Treatment may range from physical therapy to surgery, depending on the severity of the tear.

References:

orthoinfo.aaos.org/en/diseases--conditions/slap-tears

4. Rotator Cuff Injuries: Strain or Tear

The rotator cuff is a group of four muscles and their associated tendons that stabilize the shoulder joint. A strain or tear in the rotator cuff can cause shoulder popping or cracking during movement.

Common Causes:

Overuse injuries: Repetitive overhead activities, such as weightlifting or throwing sports, can lead to rotator cuff injuries.

Acute injuries: Falling on an outstretched arm or lifting something too heavy can also cause a tear.

Symptoms to Watch For:

Pain, especially when lifting the arm

Weakness in the shoulder

Difficulty performing everyday activities, such as reaching behind your back

Is it a cause for concern? Rotator cuff injuries can be serious and often require medical attention. If you suspect a rotator cuff injury, it's important to see a healthcare professional for an accurate diagnosis and appropriate treatment.

References:

mayoclinic.org/diseases-conditions/rotator-cuff-injury/symptoms-causes/syc-20350225

5. Joint Hypermobility: Excessive Flexibility

Some people have joints that are more flexible than normal, a condition known as joint hypermobility. This increased range of motion can cause the shoulder joint to move more than it should, leading to popping or cracking sounds.

Signs of Joint Hypermobility:

Ability to easily bend your thumb to touch your forearm

Frequent joint dislocations or subluxations (partial dislocations)

Popping or cracking sounds in multiple joints

Is it a cause for concern? While joint hypermobility isn't necessarily harmful, it can increase the risk of injuries, including dislocations and sprains. If you're hypermobile, it’s important to strengthen the muscles around your joints to provide better stability.

References:

nhs.uk/conditions/joint-hypermobility/

6. Arthritis: Wear and Tear of the Joint

Arthritis, particularly osteoarthritis, can lead to the degradation of cartilage in the shoulder joint. As the cartilage wears away, the bones may rub against each other, causing a grinding or popping sound during movement.

Symptoms to Watch For:

Pain, particularly during or after exercise

Stiffness in the shoulder, especially in the morning or after periods of inactivity

Swelling around the joint

Is it a cause for concern? Arthritis can significantly impact your quality of life. If you suspect arthritis is causing your shoulder to pop or crack, it's important to consult with a healthcare provider. Early intervention can help manage symptoms and slow the progression of the disease.

References:

arthritis.org/diseases/osteoarthritis

7. Shoulder Impingement: Pinching of the Rotator Cuff

Shoulder impingement occurs when the rotator cuff tendons are pinched between the bones of the shoulder. This can lead to inflammation, pain, and a popping or cracking sensation during certain movements.

Common Causes:

Repetitive overhead activities, such as swimming or weightlifting

Poor posture, which can contribute to abnormal shoulder mechanics

Symptoms to Watch For:

Pain when lifting the arm, especially above shoulder height

A sensation of weakness or difficulty moving the arm

A feeling of catching or popping in the shoulder during certain movements

Is it a cause for concern? Shoulder impingement can lead to more serious conditions, such as rotator cuff tears, if not addressed. Early treatment, including rest, physical therapy, and possibly corticosteroid injections, can help alleviate symptoms and prevent further damage.

References:

mayoclinic.org/diseases-conditions/shoulder-impingement-syndrome/symptoms-causes/syc-20350747

8. Glenohumeral Instability: Shoulder Joint Looseness

Glenohumeral instability occurs when the shoulder joint is too loose and moves out of its normal position. This can happen due to repetitive stress, trauma, or genetic factors. The instability can cause the shoulder to pop or crack during movement.

Types of Instability:

Traumatic instability: Often caused by a dislocation or injury.

Atraumatic instability: Occurs without a specific injury and is often related to joint hypermobility.

Symptoms to Watch For:

A feeling of the shoulder "slipping" or "catching" during movement

Pain or discomfort, particularly during overhead activities

Recurrent shoulder dislocations

Is it a cause for concern? Glenohumeral instability can lead to recurrent dislocations and long-term damage to the shoulder joint. If you experience symptoms of instability, it's important to seek medical advice. Treatment may include physical therapy to strengthen the shoulder muscles or surgery in more severe cases.

References:

orthoinfo.aaos.org/en/diseases--conditions/shoulder-instability

Conclusion

Shoulder popping or cracking during workouts can be caused by various factors, ranging from harmless gas bubble formation to more serious conditions like rotator cuff tears or shoulder instability. Understanding the underlying cause of these noises is crucial to determining whether they require medical attention. If the popping is accompanied by pain, weakness, or a sense of instability, it's important to consult a healthcare professional for a thorough evaluation.