Side Knee Pain During Sports Activities: What it Means

Side knee pain during sports activities is most commonly caused by iliotibial (IT) band syndrome, meniscus injuries, or collateral ligament sprains. Pain on the outside of the knee is often linked to IT band syndrome, while pain on the inside may indicate a meniscus or medial collateral ligament (MCL) injury. Symptoms such as swelling, instability, locking, or difficulty bearing weight may require prompt medical evaluation.

What Does Side Knee Pain During Sports Mean?

Side knee pain usually indicates irritation, overuse, or injury involving the structures that stabilize the knee. 

The most common causes include:

• Iliotibial (IT) band syndrome

• Meniscus tears

• Medial collateral ligament (MCL) sprains

• Lateral collateral ligament (LCL) injuries

The location of the pain, how it started, and whether symptoms such as swelling or instability are present can help identify the underlying cause.

Is the Pain on the Inside or Outside of Your Knee?

This distinction is often the first step sports medicine specialists use when evaluating athletes with knee pain.

Common Causes of Side Knee Pain During Sports

Sports medicine clinicians commonly assess side knee pain by evaluating where the pain occurs, the sport involved, and whether symptoms developed suddenly after an injury or gradually from repetitive activity.

1. Iliotibial (IT) Band Syndrome

IT band syndrome is one of the most common causes of outer knee pain in runners, cyclists, and endurance athletes (1). It develops when repetitive knee flexion and extension create irritation along the outer portion of the knee.

Common symptoms include:

• Burning or aching pain on the outside of the knee
• Pain that worsens during running or cycling
• Increased discomfort when running downhill
• Symptoms that improve with rest

Research published in the sports medicine literature identifies IT band syndrome as one of the leading overuse injuries affecting runners and cyclists (2).

2. Meniscus Injury

The meniscus is a cartilage structure that helps absorb shock and stabilize the knee joint. Meniscus tears frequently occur during sports that involve twisting, pivoting, cutting, or sudden changes in direction.

Common symptoms include:

• Sharp pain on either side of the knee
• Swelling within hours or days
• Clicking, catching, or locking sensations
• Difficulty fully straightening the knee

Meniscal injuries are among the most common knee injuries in athletes and are particularly prevalent in soccer, basketball, football, and tennis players.

3. Medial Collateral Ligament (MCL) Sprain

The MCL runs along the inner side of the knee and helps prevent excessive inward movement.

Common symptoms include:

• Pain along the inside of the knee
• Tenderness over the ligament
• Discomfort during side-to-side movements
• Mild to moderate instability

MCL injuries commonly occur during contact sports and may result from direct blows to the outside of the knee (3). 

4. Lateral Collateral Ligament (LCL) Injury

The LCL stabilizes the outer portion of the knee and is less commonly injured than the MCL.

Common symptoms include:

• Pain on the outside of the knee
• Tenderness along the outer joint line
• Instability during cutting or pivoting movements
• Difficulty with rapid directional changes

How to Tell Which Injury You May Have

While a professional assessment is needed for an accurate diagnosis, symptom patterns can provide useful clues.

No single symptom can confirm a diagnosis, but these patterns help guide further evaluation.

When Should Athletes Seek Medical Attention?

Athletes should seek assessment from a sports medicine physician, orthopedic specialist, or physiotherapist if they experience the following:

• Significant swelling
• Persistent pain lasting more than several days
• Knee instability
• Locking or catching sensations
• Difficulty walking or bearing weight
• Recurrent pain that returns during sports participation

Early evaluation can help prevent minor injuries from progressing into more serious conditions that may require prolonged rehabilitation.

How Side Knee Pain Is Diagnosed

Diagnosis typically involves:

1. Review of symptoms and injury history
2. Physical examination
3. Knee stability and movement testing
4. Imaging when clinically indicated

MRI is often considered the preferred imaging modality when meniscal or ligament injuries are suspected because it provides detailed visualization of soft tissue structures (4). 

Treatment Options

Treatment depends on the specific diagnosis and injury severity.

Conservative Management

Many cases improve with:

• Activity modification
• Physiotherapy
• Strengthening exercises
• Mobility and flexibility training
• Progressive return-to-sport programs

Advanced Treatment

For more severe injuries, treatment may include:

• Knee bracing
• Injection therapies
• Surgical intervention for selected meniscal or ligament injuries

Current sports medicine research published in the Indian Journal of Orthopaedics increasingly supports structured rehabilitation as a first-line treatment for many knee injuries before surgery is considered (5). 

Athletes recovering from ligament or meniscus injuries may benefit from using sports knee support braces that help improve knee stability during training and competition.

Conclusion

Side knee pain during sports activities can result from several conditions, including iliotibial (IT) band syndrome, meniscus injuries, and collateral ligament sprains. While the location and pattern of symptoms often provide clues about the underlying cause, persistent pain, swelling, instability, or locking should never be ignored. Early diagnosis and appropriate treatment can help prevent further injury, support faster recovery, and allow athletes to safely return to their sport. If side knee pain continues despite rest or interferes with performance, consulting a sports medicine specialist can help identify the cause and create an effective rehabilitation plan.

References

1. Gupta P, Yadav D, Singh K, Bhattacharjee S. Iliotibial band friction syndrome: A common cause of lateral knee pain in long-distance runners. Journal of Marine Medical Society. 2022;0(0):0.
2. Friede MC, Innerhofer G, Fink C, Alegre LM, Csapo R. Conservative treatment of iliotibial band syndrome in runners: Are we targeting the right goals? Physical Therapy in Sport. 2022 Mar;54:44–52.
3. Naqvi U, Sherman A l. Medial Collateral Ligament (MCL) Knee Injuries [Internet]. PubMed. Treasure Island (FL): StatPearls Publishing; 2020. Available from: https://www.ncbi.nlm.nih.gov/books/NBK431095/ 
4. Noorelahi Y. Comparative Diagnostic Accuracy of MRI and Ultrasound in Meniscal Tear Detection: Evaluating Reliability and Limitations Against Arthroscopic Outcomes. Buemi F, editor. Radiology Research and Practice [Internet]. 2025 Jan;2025(1). Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC12680451/ 
5. Dhillon M. Current Concepts in Sports Injury Rehabilitation. Indian Journal of Orthopaedics. 2017;51(5):529.