Introduction

Cycling has numerous benefits in improving cognitive function, reducing and preventing depression, risks of cardiovascular diseases, diabetes and obesity.¹ Depending on the population, some cyclists are indoors in a gym using a stationary bike, while others cycle professionally, or for leisure to relax and manage stress. Another category of cyclists are those for which cycling is a form of transportation. Thus, it appeals to people of all ages, and is encouraged for improved quality of life.² 

However, poor technique, overuse/overload, and predisposing anatomical variations can lead to a common but painful injury to the tendon, referred to as patellar tendonitis.³ In this article, you will better understand the symptoms and management to prevent and manage patella tendinitis and return to pain-free cycling.

What is patellar tendonitis? 

Patellar tendonitis, also called jumper's knee, is a musculoskeletal condition that presents with pain at the patella tendon, located directly below the knee cap (patella).⁴ The pain is usually a result of overload and micro tears of the patella tendon without proper recovery.³ 

An accumulation of these microtears eventually leads to more severe cases. The patella tendon can be properly felt between the inferior pole of the patella running into its insertion at the top of the tibia bone. The quadriceps in the thigh becomes the patella tendon after its fibres cross the knee cap. It functions to straighten the knee joint.⁵

Tendonitis is associated with overuse, especially during cycling.⁶ It can also be caused by a minor fall directly on the knee or hitting one of the bars on the bicycle.⁷ Some of the risk factors include:⁸

• Increased amount of time spent training
• Poor muscle flexibility
• Previous injury or rupture 
• Persons with back pain 
• Family history 
• Age 

The pain usually comes on with generalised tightness around the thigh muscles. A mild swelling at the front of the knee may also occur after prolonged cycling. In more severe cases, it can begin to affect simple activities of daily living, like showering and dressing, thereby impacting quality of life.⁹ 

Tendinitis, tendonitis or tendinopathy?

Contrary to previous belief, it has been established that it is a degenerative change to the tendon after the initial inflammation, rather than the inflammation itself, that is the cause process of the injury.¹⁰ Thus, your clinician may use the term 'patellar tendinopathy' when describing this injury. 

However, some of the literature will still refer to it as tendinitis, tendonitis or tendinosis. Nevertheless, it is a condition with a background of extensive research, including well-reported outcomes in its prevention and treatment.

Causes of patellar tendonitis in cyclists

These include:

• A sudden increase in cycling times (increased mileage) or the intensity of cycling
• Excessive weight can put increased pressure on the knees, hence stressing the tendons
• Poor flexibility in the legs and ankle puts the patella tendon at risk of injury
• Weakness of the legs reduces cycling efficiency and puts more strain on the tendons, making it prone to injury
• Poor footwear choices
• Saddle height: either too high or too low can affect the body's biomechanics, leaving it prone to injury
• Incorrect cleat alignment

What happens to the knee during cycling?

During cycling, there are two phases: the power phase and the recovery phase.¹¹ The knee generates the force required to set the bicycle in motion in the power phase. These forces are generated by the muscles attached to the knee - the quadriceps and hamstrings - as well as the glutes. Alternatively, the muscles of the calf, the spine and upper limbs are used to maintain stability in the recovery phase. 

The quadriceps is a group of four muscles - vastus lateralis, vastus medialis, rectus femoris, and the vastus intermedius.¹¹ The quadriceps are particularly important in cyclists prone to patellar tendinopathy because the quadriceps are located close to the tendon. The patella tendon connects bone to bone and thus to prevent increasing stiffness and risk of injury, flexibility exercises are encouraged.¹²

Phases of cycling

Power phase

Imagine that the foot moves through one cycle on a clock, the power phase starts from 12 o'clock to 6 o’clock. From 12 o’clock to 3 o’clock, the gluteal muscles initiate the movement until about 3 o’clock. The highest amount of force generated in the power phase is from 3 o’clock to 5 o'clock by the quadriceps. 

Cyclists with patellar tendonitis will frequently observe an aggravation of their pain during the power phase, when the quads are active. The force generated is then translated to the pedal from 5 o’clock to 6 o clock, where this stability is further maintained by the calf muscles.¹¹

Recovery phase 

In this phase, the patella tendon is under a lesser compressive load. Other muscles help to finish off the pedal cycle. These muscles include the shin muscles (tibialis anterior) and the hamstrings. Although the quadriceps and patella tendon are not active in this phase, contraction of the active muscles in the recovery phase are important to prevent uneven distribution of forces.¹¹

Bike fitting and patellar tendonitis

In protecting the knee and ensuring stability, the saddle height is very important.¹³ It is recommended that the knee should maintain an angle when the foot is on the pedal. It is suggested that a knee flexion angle of 25-30 degrees with a higher saddle height is maintained to prevent knee injuries.¹⁴ 

The appropriate angles will vary depending on the age, height and leg length. Personalised fittings from appropriate professionals can also be sought out by participants wishing to optimise their riding experience, i.e., comfort and injury prevention. 

Bike riding and patellar tendonitis

For most non-traumatic cases, patellar tendonitis usually arises after prolonged periods of cycling, especially among professionals in training. Therefore, another factor to consider is cadence, defined as an increase in the number of revolutions per minute.¹⁵ 

A cyclist will generally experience increased pain with a higher number of revolutions and increased muscle power. Riding while standing on the pedals could help ease the pain as there is reduced knee flexion and cadence, producing lesser compressive forces on the patella tendon.¹⁶ 

Professionals will usually want to have experts measure other aspects of the bike such as the crank length and any advice on bike gears. A well-adjusted personalised bike will improve muscle efficiency and prevent excessive strain on the tendons.¹⁶ 

Diagnosis 

The diagnosis is mainly through the presentation of pain with activity. In more severe or unresolved cases, an ultrasound or MRI may be used to visualise the changes to the tendon.

There are four stages of progression if patella tendonitis is not properly managed:¹⁷

1. Pain following the activity - cycling
2. Pain during activity but no limitation of performance/not affect
3. Pain with or following activity with limitation of performance at optimal level
4. Patellar tear or rupture requiring surgical intervention

Stage 4 ruptures are very uncommon and will mostly result from direct trauma or very poorly managed stage 3. 

Management

If pain arises only with cycling (stage 1), you can apply an ice pack to the front of the knee. The recommended time is 15-20 minutes, at least 3 times a day. Usually, this can help settle the pain. Load management is an important aspect in managing tendonitis. It is advised that you pause your usual cycling activity until the symptoms start to settle. 

In milder cases, you might still cycle but have to reduce the frequency to avoid overloading.¹⁸ Physiotherapists are usually experts at prescribing personalised programs to promote full recovery. They will also assess other muscles in your lower limb and back to explore other contributory causes. 

The exercises advised will usually include strengthening and stretching of the muscles around the core, hips, knees, and ankle. You can also use a foam roller to increase the flexibility in your quadriceps and hamstrings. A resistance band is a simple way to start strengthening exercises, especially, for your quadriceps. Some cyclists can also try taping.¹⁸ However, there is no general consensus on taping effectiveness, and might only be helpful in the short term.

It is important to book an appointment with your physiotherapist or doctor, preferably one with experience in managing cycling-related injuries for further expert management. 

For severe and chronic cases, the following might be incorporated into the treatment plan by your clinician:¹⁹

• Non-steroidal anti-inflammatory drugs (NSAIDs)
• Corticosteroid injections 
• Platelet-rich plasma injections 
• Modalities such as extracorporeal shockwave therapy (ESWT) 

The risks associated with each treatment will be discussed with you.

Generally, you can return to cycling when the symptoms are no longer aggravated. Listen to your body and follow proper management to prevent re-injury. Most cases will not require surgery, and physical therapy with pain relief medication is the current recommendation.¹⁹

Summary

1. Cycling is a physical activity that improves health. Due to poor technique or bike fit, causing increased force on the knee, cyclists can develop pain from patellar tendonitis
2. Patellar tendonitis presents with pain at the anterior part of the knee just below the knee cap
3. It is best to manage the load on the knee by pausing cycling until the symptoms settle
4. The physiotherapist will assess and advise on exercises to manage the pain
5. Other treatment options can be provided by a clinician depending on the severity
6. Cyclists can return to cycling once patellar tendonitis symptoms have settled