Knee pain: Patellofemoral pain syndrome

In cycling, our knees are always on the move. If a rider maintains a cadence of 90 RPMs, they will complete 5,400 pedal strokes in an hour! That’s a lot of knee bending and straightening. While cycling can be a safe haven for some knee injuries since it is considered a non-weight bearing sport, the chronic and repetitive bending and straightening of the joint can create problems of its own. In fact, one study indicated that between 15 – 33 percent of endurance cyclists will experience knee pain.¹

Related:

• Training: Knee pain while cycling — IT Band Syndrome
• Patellar tendonitis: Prevention and rehabilitation
• Five tips to prevent knee pain

Knee pain hurts enough as it is, but if you’ve experienced an injury you’ve also probably experienced the emotional pain of not knowing what’s wrong. There are so many different culprits of knee pain and if you open and search in “Doctor Google,” you’ll probably read about a few that sound pretty scary. IT Band Friction Syndrome, Quadriceps tendonitis, Patellar Tendonitis, and chondromalacia are just a few knee injuries that haunt cyclists around the world. That said, one of the most common injuries of all, is likely Patellofemoral Pain Syndrome (PFPS) or in more colloquial terms, generalized knee pain.

What is Patellofemoral Pain Syndrome?

PFPS is a diagnosis of exclusion. That means that once you have ruled out all other knee injuries, PFPS is what is leftover. The reason for this is because PFPS is a generalized condition that usually refers to knee pain in the front of the knee, around the kneecap, or behind the knee cap.

This means that if you have been diagnosed or think you have PFPS in many ways it can be a relief. It means that you aren’t being hindered by a different, more significant injury such as something being torn or broken. On the other hand, it can open a whole other can of worms. ‘If my knee just generally hurts, what is causing it?’ When it comes to PFPS, that is the million-dollar question. The cause of PFPS varies from one patient to another and is usually multi-factorial.

Before we dive into what some of these root causes and contributing causes can be, I want to make one more thing clear: Just because your knee pain is “general” and doesn’t come with a fancy MRI of the torn ligaments or muscles, doesn’t mean it doesn’t hurt and pain can hinder your performance. In fact, PFPS can be quite painful which makes getting the cause of the condition nailed down even more important.

Contributing Factors of PFPS

There are three main areas in which we begin our investigation to discover the underlying cause of PFPS. Usually, you will find your answer in one of these three realms, or in a combination of the three.

1. Anatomical and Biomechanical Factors

There are many anatomical and biomechanical factors that can contribute to PFPS. I will highlight the most prevalent causes below. Some of these factors are congenital (meaning that you were born with it) and, for others, some of these factors may be learned.

Patellar Tracking: Poor patellar tracking can be a contributing factor to PFPS. The knee cap sits on top of the thigh bone or femur in an anatomical groove called the trochlear groove. The knee cap normally tracks along inside of this groove. Anatomical abnormalities such as malalignments, muscular imbalances, or congenital conditions can cause the knee cap to be pushed or pulled slightly out of this groove. This is one reason that popping and clicking is also a sign or symptom of PFPS.

Pronation: Excessive pronation of the foot can also be a contributing factor of PFPS. Pronation is when the foot rolls inward. With excessive pronation, you may see the foot roll inward so much that the outer heel begins to lift off of the ground as you fall into the arch of your foot. Excessive pronation will be felt all the way up the kinetic chain as the foot posture leads to rotated lower legs, and subsequently knee compensations.

Knee Valgus: Knee valgus is when your knees are turned or bent in toward each other. This posture can result in a knee cap that pushes outward or tracks to the side of your knee.

Bike Fit: As cyclists, our bikes are almost an extension of us. While sometimes our imbalances or biomechanical factors are learned or congenital, sometimes they are just a result of us manipulating our own bodies to fit our bike. An improper bike fit can be a contributing cause of PFPS. For example, improper cleat position can cause excessive pronation. A professional bike fit is an excellent place to begin your investigation toward the cause of your PFPS, and ultimately may eliminate your pain!

2. Muscular Imbalances

Just like the anatomical factors and biomechanical factors, there is a myriad of muscular imbalances that can contribute to PFPS. Here I will discuss the most common imbalances and I’ve included an exercise or two, to address each one. While the singular exercise will not make up an entire prevention or rehabilitation routine, it may give you motivation to research more exercises to benefit those muscles.

Weak Quadriceps: As cyclists, we may think we have quads of steel, but you may be overlooking one thing, the ‘quad’ in the quadricep indicates that there are four muscles involved. It can be all too easy for one of the quadriceps muscles to pick up the slack or over-power the others, especially if you have ever sustained an injury to your quadriceps.

Isometric Contractions: Sit on the ground with your legs straight out in front of you. Contract your quads and hold for 5-10 seconds. Focus on making sure that the portion of your quad toward the inside is contracting fully. You may even rotate your feet outward slightly to help with the activation.

Wall Ball Squats: With a swiss ball on your back against the wall, slowly squat into a 90-degree position and then slowly return back to standing without locking your knees out entirely.

Tight IT Band: While the IT Band is not a muscle, it can still be overly tight and an overly tight IT band can influence the tracking of the knee cap. In fact, athletes who experience IT Band Friction Syndrome will often also experience PFPS.

Foam Roll: Try foam rolling in order to help reduce tension on the IT band before and/or after exercise.

Tight Gastrocnemius: Put simply, tight calf muscles. Even tight calf muscles can have an influence on your knees. Stretching and foam rolling are beneficial.

Downward Dog: Begin in a pushup position, then walk your hands slightly closer to your feet and stick your glutes up into the air. Push back into your heels (although they might not touch the ground) and feel the stretch. Pedal your feet to stretch them one at a time.

Hamstring Tightness and Weakness: Hamstring tightness and weakness can both be contributing factors toward PFPS. Cycling is often considered to be a quad-dominant sport, so sometimes we need to give a little extra attention to the hamstrings.

Hamstring Curls on Swiss Ball: Lay on your back and place your feet on a swiss ball. Then lift your glutes off of the ground into the bridge position. Pull the ball with your feet toward you.

Hamstring Stretch: Lie on your back, with both legs straight, and lift one of your legs off of the ground. Use a towel hooked around your foot to gently pull your leg back toward yourself, while keeping it straight.

Weak Hip Flexors and Adductors: Just because your hip flexors and groin muscles are tight, does not mean they are strong.

Sidelying Adductor Exercise: Lay on your side with your top leg slightly behind your bottom leg. Then lift the bottom leg upward.

Leg Lifts: Lying on your back, lift one leg off of the floor at a time while keeping it straight. You can use a band in order to increase the difficulty.

Weak External Rotators/Abductors: Without strong hip muscles, your knees can easily move inward into the genu valgum position. As cyclists, we rarely work these muscles because we are always pedaling forward and rarely moving side to side:

Clam Shells: Lying on your side with your knees stacked on top of each other. Lift the top knee upward while keeping your feet together.

3. Training Errors
Finally, training errors can lead to PFPS. PFPS can be brought on when training duration or intensity increases too drastically or too quickly. It is generally recommended to limit increases to around 10 percent of volume per week during a training program.

Listen to Your Body

Many people will say that pain is your body’s way of telling you that something is wrong. PFPS seems like the perfect example of that. When your body expresses its discomfort as pain in your knees, the real call to action may be in an entirely different location in your body. If exercises and/or adjustments don’t alleviate your knee pain be sure to speak with a healthcare professional about your discomfort. While your knees may be a driving force behind the pedals, don’t let knee pain drive you to quit.

Sources

1. Bini, Rodrigo, and Alice Flores-Bini. “Potential Factors Associated with Knee Pain in Cyclists: a Systematic Review.” Open Access Journal of Sports Medicine, Volume 9, 2018, pp. 99–106., doi:10.2147/oajsm.s136653.
2. Starkey, Chad, and Sara Brown. Examination of Orthopedic and Athletic Injuries. Jaypee Brothers Medical Publishing, 2015.
3. Higgins, Michael. Therapeutic Exercise: from Theory to Practice. Jaypee Brothers Medical Publishers, 2012.