Knee pain is the most common pain for cyclists. There are many causes, but the most common cause is your bike fit. So let’s break down the top fit and biomechanical issues that may hurt your knees.

Front or anterior knee pain – Pain at the front of the knee is the most common issue. Typically, the seat height is too low. As a result, the knee excessively bends near the top of the pedal stroke. 

If there is an increased bend of the knee, increased force is placed on the joint below your kneecap, known as the patellofemoral joint. Eventually, your patellofemoral joint will scream out in mercy.

Steps To Getting Rid of Knee Pain

Start with the Foundation of the Fit – First, make sure that your saddle is level or near level. I then start at the foundation or the foot when addressing bike fit issues. Step one is to ensure that the knuckle of the big toe lines up with the pedal axis. This joint is known as the first metatarsal phalangeal joint.

Aligning the knuckle of the big toe with the pedal axis is the most common starting point for roadies. There are exceptions to the rule, but I recommend starting with this position. You may have to turn over your shoe and move the cleat. In addition, to move the cleat forward or backward to achieve this position, consider the inside (medial) or outside (lateral) position of the cleat. I suggest starting in the middle and adjusting based on your symptoms and comfort. Once the foundation has been adjusted, it is time to move up to the seat post.

The height of the seat post is determined by the knee bend when the foot is at the bottom of the pedal stroke and at 3 o’clock. At the bottom of the pedal stroke, the knee bend should be about 20 degrees. This angle is formed by the greater trochanter of the femur and the lateral malleolus of the ankle. The greater trochanter of the femur is the bump on the outside of the hip. The lateral malleolus is the bump on the outside of the ankle.

To achieve this angle, you may need to raise or lower the height of your saddle, but make sure that your saddle is always level.

Next, check out the 3 o’clock position. Make sure that your ankle is at 90 degrees before assessing this position. Then use a plumb bob or straight line. The line is positioned directly in front of the kneecap and should align with the pedal axis. If the line is too far forward, then move the saddle back. If the line is too far backward, then move the saddle forward.

When making your measurements, you have many options. You can use a video analysis app. The following are a few options:
Dartfish
Bike Fast Fit App

Using an app is a great way to take measurements, but there can be significant errors. For example, if the angle of your camera or phone is not just right, your measurements will not be accurate.

You can also go old school as discussed above and take the measurements using a goniometer and a plumb bob. When doing this, you can put your bike on a trainer or lean against a wall. A partner would be helpful when using the goniometer to measure the knee angle at the bottom of the pedal stroke.

As you may see, there are many things to consider when finding the right position for the knees. It is best to see an experienced bike fitter in your area in the ideal world. If you have seen a bike fitter and are still experiencing pain at the front of the knee, consider moving the saddle up only 2 mm. If you are not mechanically comfortable, consider visiting your local bike shop to adjust. It would be a bummer to crack a carbon seat post. Test this position for about two weeks of consistent riding. Bike fitting is an art and a science. The body is unpredictable. The fitter will get you started on the suggested safe positions, but time will guide you to your right position.

Increased Genu Valgum

Genu valgum is the medical term to describe a knocked-kneed position.

If your knees are close to the top tube when pedaling, it stresses the ligaments on the inside of the knee and alters the tracking of the kneecap. The kneecap or patella typically moves up and down in a rather straight groove when pedaling. If your knee is not straight, then this groove is not straight. As a result, the knee’s cartilage begins to break down gradually. At first, this breakdown is not painful because the superficial layers of the cartilage are not innervated or connected to nerves. As a result, you may hear crunching or crepitus. In time, this crunching becomes painful because the deeper layers of cartilage are connected to nerves. This pain is an indication that you’re wearing away the superficial layers of cartilage. Your body has a way of giving you a heads up. You just need to listen to it.

Step one is to always start with the foundation, as discussed above. Then, you have a couple of options. I like to keep things simple and minimal. So, start with option one.

Option 1: The goal is to make sure that the knee and the ankle move in a straight line when pedaling. This line may be at an angle, but it is always straight.

In a knock-kneed case, the knee is moving too far inward. Therefore, move the cleat on your shoe outward. This new position will move the knee inward and in line with your foot. If this doesn’t reduce the knee pain in a few weeks, proceed to option two.

Option 2: Consider varus wedges. A varus wedge can be placed inside the shoe or between the cleat and the shoe. Option two is heading into professional territory. I recommend seeing a professional fitter or a physical therapist with bike fit training. Placing a wedge under the foot elevates the inside of the foot. If you elevate the inside of the foot, then the knock-kneed position is reduced.

Increased Genu Varum

Genu valgum is the medical term to describe a bow-legged position.

A bow-legged position compresses the inside of the knee joint, gaps or stretches the soft tissue on the outside of the knee, and alters the tracking of the kneecap. Typically, a bow-legged position can cause pain at the front and inside of the knee. The pain at the inside of the knee is related to compression of the inside or medial meniscus. The pain at the front of the knee is related to improper patellofemoral tracking. A bow-legged problem is similar to a knock-kneed position but in reverse. Start with option one to correct the issue. If that doesn’t work, consider option two.

Be sure that your saddle height and cleat position is established as described at the beginning of this post. It’s time for option one.

Option 1: From the front, observe the alignment of your knee and ankle as you pedal. If you are bow-legged, your knee is tracking outside your ankle.

To reduce this improper alignment, move the cleat on the bottom of your shoe inward. This new position will move your foot under your knee. As a result, the alignment between the knee and your ankle should be better. Test this position for a few weeks of consistent riding. If you continue to have pain, proceed to option two.

Option 2: You are heading into professional territory again. Some professionals may use wedges to improve the alignment, but there is a straightforward trick that may help. The ultimate goal is to move the foot under the knee. This can be done by placing aluminum spacers between the pedal and the crank arm. The pedal now “pushes” the shoe and your foot under your knee. In some cases, a special pedal extension is used in more extreme cases.

I have just one word of caution with this trick. One leg may require more of a correction. Most likely, both legs are bow-legged. Try your best to balance the number of spacers or length of the pedal extension. If your correction is significantly asymmetrical, much stress is placed on your crankarm and bottom bracket.

At times, knee pain can easily be corrected by making a few adjustments. Other times, leave it up to the professionals. I would rather you be safe than sorry. In some cases, a bike fit is not so clear-cut. Someone may have a structural or functional leg length discrepancy. Certain foot types can make the fit more complicated. The point is to try the simple adjustments first and seek professional help if the simple adjustments don’t work.