Why does my knee pop while riding a bicycle?

Riding with your saddle too low or pedaling in too high a gear, commonly results in Patellofemoral Pain Syndrome (PFPS). PFPS causes your knee to pop or click because your kneecap (patella) rubs against your femur, creating a popping sound.

• A fairly strong indicator that you are experiencing PFPS is if you have knee pain or clicking consistently at the top of your pedal stroke.

• Riding in high gears

  • Instead, increase cadence and decrease resistance (ride in easier gears)

• Prolonged hill climbs

  • Ride hills in easier gear or modify route

• Sub-optimal Bike Fit

  • Improper seat height

    • 25 to 30 degrees of knee flexion of the extended leg when the pedal is at 6 o’clock position (maximum height whereby the rider is not rocking back and forth across the seat when riding)

  • Too far forward on the saddle

    • Effectively lowers the height of the saddle

  • Too long of cranks

  • Incorrect Q-factor (how far your feet are apart)

    • Read my article on Q-Factor for more info

• High mileage

• Muscular imbalances

  • Riding with a seat too low causes your quads to work significantly harder than your hamstrings, causing muscular imbalances, which are exacerbated the more and harder you ride

• Flexibility limitations

  • Muscular imbalances lead to flexibility issues

low saddle & knee pop/clicking sound

While it’s true that cycling is low impact, bicycling is also highly repetitive. So, if your pedal stroke is not optimal, issues, pain, or injuries will manifest as many cyclists average 5,000 revolutions per hour.

If you can put your foot flat on the ground or close to it while stopped, your saddle is much too low.

• I wrote an entire article about proper saddle height if you are unsure or looking for a refresher

causes of clicking or popping noises

There are two main reasons that your knee will click/pop:

• Air Bubbles (caviation)

  • Occasional (infrequently) knee popping occurs when tiny air bubbles become trapped in your knee joint and burst from the action of pedaling. This is normal and nothing to worry about.

• Pathological

  • Frequent or chronic knee popping/clicking is a cause for concern since this means your kneecap (patella) isn’t in the right position while cycling. The patella is making contact with the femur, which causes the clicking noise. There are several possible reasons, but none of them are good. Immediate BikeFitting or muscle/flexibility testing should be conducted (or visit a health care professional).

    • Osteoarthritis of the knee - Knee degeneration or wear and tear of the knee joint also causes knee noises. However, if you have osteoarthritis, there are additional symptoms, such as swelling and joint pain.

    • Frequent cycling with an improper bike setup can cause muscle imbalances, which can lead to your patella not tracking properly. The muscles around your knee start playing tug-of-war with each other, and because of the resulting imbalances, your patella (kneecap) loses out.

Also, keep in mind that It doesn’t matter what type of bike your riding; mountain, gravel, stationary, or road bike, all have the same pedal motion and knee action.

Yes. Frequent clicking or popping noises while pedaling, even without pain, should be cause for pause.

• The reason for the clicking/popping noise is because your kneecap and femur are not moving properly.

• If you continue to ride without adjusting your bike settings or address muscle imbalances (quads, calf, hamstring, & ITB), pain and injury will develop. Once you begin experiencing pain, it becomes much harder to treat.

Patellofemoral Pain Syndrome & bicycling

Patellofemoral Pain Syndrome (PFPS) is a typical cycling overuse injury with PFPS commonly known as “Biker’s Knee” and affects at least 25% of cyclists.

• PFPS (Biker’s Knee) = Pain on the FRONT of your knee or under the kneecap.

• Patellofemoral pain often presents as a gradual onset of knee pain behind or around the kneecap and is a common overuse injury experienced by hikers, cyclists, mountain bikers, runners, and triathletes.

The main causes of Biker’s Knee is riding with a seat that is too low and improper BikeFit or prolonged riding in high gears.

“Biker’s Knee” treatment

If you are experiencing frequent clicks and pops without pain, while riding, the first course of action should be adjusting your Bike Fit settings.

• Start by adjusting seat height

However, if you also have knee pain, then it’s time to go to a PT and get some corrective exercises before you go for another ride.

• If your seat is too low, your quad muscles will do the majority of the pedaling. This creates muscle imbalances. These muscle imbalances will alter how the tendons pull on your kneecap.

A simple test to look for PFPS is to do the “step-up test.”

1. Find a step that is 4 - 8 inches high

2. Perform a single leg step-up

3. Take note of where the pain is located

   • If the pain is under or around your kneecap, you may have patellofemoral pain syndrome and it’s important to seek a healthcare professional to diagnose and provide treatment. The sooner you resolve the issue the quicker you can go back to riding.

Final thought

Cycle-related injuries increase as mileage and participation increases.

Most cycling injuries are overuse or repetitive stress.

• The first step is to avoid injuries, and that starts with an optimal fitting bicycle and a balanced training regime.

Since most bicycle-related injuries are repetitive stress, they manifest as noises and pop before they progress to pain and injury. Listen to your body, and make corrections before the pop becomes pain.

Need help adjusting your seat??

Jesse is the Director of Pedal Chile and lives in Valdivia, Chile. Jesse has a Master of Science in Health & Human Performance and a Bachelor of Science in Kinesiology. Hobbies: Mountain biking, bicycle commuting, snowboarding, reading, weight-lifting, taster of craft beers, researcher, and free of any clicking or popping noises.

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Sources & references for “why does my knee pop while riding a bike”

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