Top Causes of Knee Pain in Active Adults — And Where Hillsborough, NJ Residents Can Get Help

Knee pain in active adults can come from overuse, sports injuries, cartilage damage, ligament problems or arthritis. Runner’s knee, meniscus tears, ACL injuries, IT band syndrome and osteoarthritis are among the most common causes. Where the pain is, how it started, swelling, instability and which activities aggravate it all help point toward the underlying problem.

What are the most common causes of knee pain in active adults?

The likely cause depends on your activity, age, training habits and whether the pain began suddenly or gradually. Common possibilities include:

• Meniscus tears
• ACL and other ligament injuries
• Patellofemoral pain syndrome (runner’s knee)
• Osteoarthritis
• Iliotibial band (IT band) syndrome
• Patellar tendon irritation
• Overuse and training-related injuries
• Stress injuries and fractures

Symptoms overlap, so the location and pattern of pain alone cannot reliably diagnose the problem. See a medical professional if symptoms persist, worsen or affect how you move.

1. Meniscus tears

The menisci are two pieces of cartilage between the thighbone and shinbone. They absorb and distribute force through the knee.

A tear can happen when the knee twists while bearing weight. Pivoting sports, sudden changes of direction and deep squatting all stress the meniscus, and degenerative changes can make it more vulnerable over time.

Common symptoms:

• Pain along the joint line
• Swelling or stiffness
• Pain when twisting or rotating the knee
• Catching or locking
• Difficulty fully straightening the knee
• A feeling the knee may give way

Persistent swelling, restricted movement or locking are more concerning. TeamMD’s Hillsborough orthopedic team offers minimally invasive treatment options for meniscus tears, with recovery plans built around your routine.

2. ACL and other ligament injuries

The anterior cruciate ligament (ACL) helps stabilize the knee. Injuries commonly occur during sudden stops, jumps, landings, pivots or changes of direction, as in basketball and soccer.

What does an ACL injury feel like?

• A popping sensation at the time of injury
• Rapid swelling
• Knee instability
• Difficulty bearing weight
• Pain after a sudden pivot or landing

Not every knee injury with a pop is an ACL tear, so the symptom alone isn’t enough for a diagnosis. The sports medicine team at TeamMD Hillsborough evaluates ligament injuries and builds a plan around the injury and your activity goals.

3. Patellofemoral pain syndrome (runner’s knee)

Pain around or behind the kneecap is commonly linked to patellofemoral pain syndrome. It often develops gradually rather than from one obvious injury. Running, jumping, squatting and repeated knee bending can aggravate it, and a sudden jump in training volume or muscle weakness may contribute.

Typical symptoms:

• Dull, aching pain at the front of the knee
• Pain when running
• Discomfort on stairs
• Pain with squatting or kneeling
• Pain after sitting with the knee bent for a long time

Treating runner’s knee well means finding what’s driving it, such as movement patterns or muscle imbalance, not just calming the pain. That is the approach TeamMD’s Hillsborough specialists take.

4. Osteoarthritis

Being active doesn’t make you immune to osteoarthritis. Knee osteoarthritis changes the joint in ways that can cause pain, stiffness and reduced function. Symptoms may be more noticeable during or after activity, and also after periods of inactivity.

Common symptoms:

• Aching knee pain
• Stiffness
• Reduced range of motion
• Pain with activity
• Difficulty with certain movements

Treatment depends on severity, symptoms and your goals. TeamMD’s orthopedic care covers knee arthritis, from conservative options to partial or total knee replacement when appropriate. If arthritis pain keeps returning, pain management treatments in Hillsborough can help you keep moving while the joint is managed. You can also read about TeamMD’s approach to joint pain.

5. Iliotibial band (IT band) syndrome

IT band syndrome causes pain along the outside of the knee. It’s often tied to repetitive activity like running and cycling. Unlike an ACL or meniscus injury, the discomfort tends to build gradually as training continues.

Outside-of-knee pain that keeps appearing during runs or rides deserves attention if it continues after you modify your activity.

6. Patellar tendon problems

The patellar tendon connects the kneecap to the shinbone and transmits force when you straighten your knee. Repeated jumping, running or explosive movements stress it, and it can cause pain at the front of the knee during loading activities.

Persistent tendon pain shouldn’t automatically be dismissed as “just soreness.” The right treatment depends on severity and cause.

7. Overuse and training-related knee pain

Not every knee problem starts with a single injury. Pain can build when activity volume or intensity rises faster than your body can adapt. Examples:

• Suddenly increasing running mileage
• Adding more hill work
• Increasing jumping or sprinting sessions
• Returning to sport after a long break
• Repeating the same movement without enough recovery

The useful question isn’t “Did exercise cause my knee pain?” It’s “Is my current activity exceeding what my knee can tolerate?” The answer helps decide whether activity changes and rehab are enough or the knee needs evaluation for an underlying injury.

8. Stress injuries

Repetitive impact can affect bone as well as soft tissue. Stress fractures develop from repeated loading and are especially relevant to runners and other athletes. Pain that becomes more localized, persistent, or present even at rest should not be ignored. For a closer look at runners’ lower-leg pain, see our guide to shin splints vs. stress fractures.

TeamMD’s Hillsborough sports medicine team treats stress fractures, using evaluation and imaging when appropriate to confirm the injury and set a recovery timeline.

Knee pain causes at a glance

How can you tell if knee pain is from an injury or overuse?

Start with how the pain began.

Sudden pain after an event such as a twist, hard landing, collision, sudden stop or fall may point to an acute injury like a ligament or meniscus tear.

Gradual pain over days or weeks while increasing mileage, training more often, adding new exercises or repeating the same activity makes overuse or load-related conditions more likely.

Gradual pain isn’t automatically minor, though. Persistent symptoms can still need professional evaluation.

When should you see a doctor for knee pain?

Consider an evaluation if knee pain:

• Continues despite modifying activity
• Keeps returning when you resume exercise
• Causes persistent swelling
• Limits your normal activities
• Causes catching or locking
• Makes the knee feel unstable
• Comes with significant stiffness or reduced movement

Seek urgent care after a significant injury if you can’t bear weight, have severe pain, substantial swelling or an obvious deformity, or can’t move the knee normally. A red, warm, swollen knee with fever also needs prompt medical attention. In an emergency, call 911.

Not sure whether your knee needs a closer look? Book an appointment or call us. TeamMD Hillsborough often has same-week availability and accepts most major insurance plans. Check your insurance.

How is knee pain treated?

Treatment depends on the cause, severity and your activity goals. Depending on the diagnosis, it may include:

• Activity modification
• Physical therapy and rehabilitation
• Strength and mobility work
• Bracing or orthotics
• Medication when appropriate
• Injections in selected cases
• Minimally invasive procedures
• Surgery when conservative treatment isn’t enough or a structural injury requires it

At TeamMD Hillsborough, care begins with evaluation and conservative treatment when appropriate. Minimally invasive procedures or surgery come only when needed, followed by rehabilitation and follow-up. The sports medicine team also offers rehabilitation, bracing and orthotics, PRP injections and minimally invasive orthopedic procedures for appropriate conditions. When pain lingers despite rest and rehab, pain management treatments in Hillsborough can be discussed alongside rehabilitation, depending on your diagnosis.

Can you keep exercising with knee pain?

That depends on the cause. Mild soreness after an unfamiliar workout is different from pain with swelling, instability, locking or a specific injury. Until you know the cause, avoid activities that clearly increase your symptoms. A sports medicine professional can help you adjust training while keeping appropriate activity and rehab going. If knee pain keeps interrupting your training, ask about pain management treatments in Hillsborough during your evaluation so recovery doesn’t stall.

The goal isn’t to eliminate movement. It’s to find the right amount and type of movement for your knee while it recovers.

Frequently asked questions about knee pain in active adults

What is the most common cause of knee pain in active adults?
No single cause explains every case. Overuse conditions, patellofemoral pain, tendon problems, arthritis and acute meniscus or ligament tears can all be responsible. The cause depends on your symptoms, activity and injury history.

Why does my knee hurt after running?
Running can aggravate patellofemoral pain, IT band syndrome, tendon problems and stress injuries. A sudden increase in mileage or intensity can also cause overuse pain.

Why does my knee hurt when I squat?
Squatting loads several structures around the knee. Pain can come from patellofemoral pain, meniscus problems, tendon irritation or arthritis. Where it hurts and what it feels like help determine what to evaluate.

Does a popping knee mean I tore my ACL?
No. A pop can occur with several knee injuries and doesn’t diagnose an ACL tear by itself. If it’s followed by swelling, instability or trouble bearing weight, get the knee evaluated.

Can a meniscus tear heal without surgery?
It depends on the tear’s type, location and severity, and on your symptoms. Some tears can be managed without surgery, while others need a procedure.

Do I need an MRI for knee pain?
Not necessarily. Imaging depends on your history, exam findings and the suspected condition. Your provider will decide whether it’s appropriate.

How long should I wait before getting knee pain checked?
There’s no single timeline. Pain that persists, returns, limits activity, or comes with swelling, locking or instability is worth discussing with a medical professional.

Can I prevent knee pain while staying active?
You can’t prevent every injury, but gradual training progression, good recovery, and strength and movement work can lower your risk. Addressing pain early may also prevent ongoing irritation or compensation.

Where can I get knee pain evaluated in Hillsborough, NJ?
TeamMD’s Hillsborough office at 501 Omni Drive offers orthopedic and sports medicine evaluation for knee conditions.

Get Started for your Knee pain treatment in Hillsborough, NJ

If knee pain is keeping you from running, working out, playing sports or enjoying daily life, identifying the cause is the first step.

TeamMD’s Hillsborough orthopedic team evaluates and treats knee conditions including meniscus tears, ACL injuries and arthritis, with on-site digital imaging and a pathway that runs from conservative care to minimally invasive procedures and rehabilitation. For sports-related injuries and overuse conditions, the sports medicine team treats active adults and athletes, including ACL injuries, runner’s knee and stress fractures. To explore pain management treatments in Hillsborough, visit us or book an appointment today.