WHY DOES MY KNEE HURT WHEN I RIDE?

In this article I delve into current thinking surrounding one of the most prevalent complaints in the knee that is reported across both mountain biking and road biking, anterior knee pain.  The article will highlight the areas that, as a physiotherapist, I would look to explore in order to effectively manage someone turning up at Tweed Valley Physiotherapy with complaints of cycling related anterior knee pain.

The most common source of knee pain in and around the kneecap or patella in cyclists relates to the patellofemoral joint.  This joint is an articulation of the patella (kneecap) and the femur (thigh bone).  The patella is in fact a bone suspended in the quadriceps tendon that then attaches to the tibia (shin bone) below the knee.  The patella runs in a groove in the femur and is helped to stay stable within that groove the muscle and soft tissue that surround it.

KNEE

 

Science tells us that pain will often be generated around the patellofemoral joint due to sub optimal tracking of the patella with in the groove.  Pressure builds up due to the increase strain and compression between the joint surfaces and this leads to tissue irritation with the source of pain potentially coming from the surrounding soft tissue, the joint surfaces or the bone.

Our understanding of the underlying behaviour of patellofemoral pain has developed over the last few years due to the increase in the number of specialist research groups in this area developing good quality studies and research that help to understand better the causes and prognosis of this condition.  We now understand that of those individuals that develop patellofemoral pain 71-91% of these people will continue to have recurrent pain over the next 20years.  It is a sticky problem that tends not to get better on its own!

So why should there be such a problem with patellofemoral pain in cycling?

Patellofemoral pain occurs primarily due to the area becoming stressed and strained due to overloading of the local tissue. Our tissue has a certain amount of load that it can tolerate, however if we push our bodies to exceed this accepted level through repetition or excessive strain, as can occur in cycling, then our tissue will tend to react through local tissue reaction and pain.

The risk of developing pain when riding is highly individual and depends on a number of variables.  We each as individuals respond differently to the load we place on our systems.  Some of us can adapt well to what we challenge ourselves to do and other may find their bodies react to changes with pain and discomfort.  The role of the physiotherapist and the rider is to navigate through all the areas that may potentially be causing the problem, identify the important ones and target a strategy to get back on track.  As physiotherapists we have always been interested in biomechanics of movement.  In cycling we are interested in the interaction of the body with the bike and highlighting inefficiency, weaknesses or restrictions that cause strain on the cyclist.  But more so now we understand the impact of so much more.  Tissue loading, inadequate recovery, training behaviours, training environment, beliefs and understanding of pain messages all play a factor in recovery.

So many aspects of cycling can therefore lead us down this path of developing such pain.  But consider this, if you are out for a 3hour ride travelling with an average cadence of 80rpm then you are completing 14 400 revolutions of your legs in one ride.  By spending time understanding tissue loading and also the biomechanics of the knee then we can very much reduce the strain placed on our knees and manage any strain present that can potentially occur due to repetitive use.

WHAT WE NEED TO KNOW - OFF THE BIKE

Muscle Function

Science tells us, as indicated earlier, that altered tracking of the patella is often present. This can be associated with reduced strength and control of the quadriceps muscle leading to movement of the patella.  It can also come from higher up and a lack of strength and control around the hip region allowing the pelvis to drop or the femur to drop inwards altering the mechanics at the patella.

Suggestion – targeted strength training of the quadriceps and hip muscle system can help reduce symptoms and improve function and performance

Flexibility

Reduced flexibility of the quadriceps complex can also be a factor due to the long periods of time spend in a seated position on the bike the muscles can adapt to that and shorten.  This can be further compounded if you spend the time out of the saddle sat at a desk!  A shortened quadriceps and anterior hip region can result in further compression of the patella to the femur.

Suggestions – consistent stretching of the affected muscle groups can reduce the compressive force exerted on the patellofemoral joint

WHAT WE NEED TO KNOW - ON THE BIKE

Load management

How our bodies respond to training and load is a fascinating subject.  The science tells us that a number of injuries can be attributed to doing too much too quickly with too much change and not enough time for adaptation or recovery.  Many individuals reporting patellofemoral pain from cycling often describe a period of increased miles, a session or two going out with faster mates, a number of steeper hill climbs.  I often describe our bodies as being like our slightly boring best friend who likes to know what is coming, does not like surprises, likes to be gradually introduced to new things and needs some quiet time once in a while.  Our bodies can very much be like that.  We are however individuals, and some of us can challenge our systems more than others without the system showing signs of strain.  It very much is about learning how your body responds to training, we don’t want to underload the tissues and create deconditioning, or overload the tissues and cause ongoing symptom aggravation. We want to find the right level to improve load tolerance and reduce pain.

Suggestion – Plan your biking endeavours and if you are looking to increase what you are doing do this gradually and give your body time to adapt

Cadence

Riding with too low a cadence. It is understood that riding with a low cadence and using increase effort to pedal will result in an increase muscle force especially through the quads and therefore through the patella. The late pull power phase and the push power phase uses high muscle activation of the quadriceps muscles and the result of this action is to produce a compressive force of the patella onto the femur.

PEDAL STROKE

Suggestions - Increasing the level of cadence by even 5% can result in reduction of forces.  Consider the terrane that you are riding if you are suffering from knee pain and adapt this to reduce the need for lower cadence work.  Try some flatter rides and easier gears.

Bike set up

There are a number of aspects of the bike set up that can influence the load exerted through the patellofemoral joint.  The key issues relate to riding with a saddle too low and too far forward.  We know from biomechanical studies that there are increases in patellofemoral joint stress at knee flexion ranges above 45degrees.  We also understand that by ensuring the knee remains over the spindle and not travelling forward of the spindle we can keep the load on the patellofemoral joint down.  Other areas to consider are if the cracks are too long, again this can result in increasing ranges of knee flexion, cleats being set too far forward and allowing for sufficient float to allow for variation of movement.  Fitting your bike to your riding can very much improve both your risk of injury but also your comfort and efficiency of riding.  Working out your window of fit can be a useful exercise to undertake.  At Tweed Valley Physiotherapy we can undertake a Physio BikeFit that involves a video assessment of you on your bike and work to help you optimise your riding position dependent on your own unique body composition and injury presentation!

Suggestion - Look at your bike set up and make small gradual changes if there is an issue.  If you are not sure what you are doing seek advice.  A Physio BikeFit at Tweed Valley Physiotherapy would be a good start!

 This article offers some information and advice regarding patellofemoral pain in cycling.  If you do suffer from un-resolving knee pain it is suggested that you do seek professional advice in order to further investigate your individual presentation.  Tweed Valley Physiotherapy offer assessment and management of musculoskeletal disorders and specialise in the management of sport and exercise related injuries and pain. Contact us on sayhello@tweedvalleyphysiotherapy.com or 07780 463343.

This article was written by Kirsty Sinclair, Clinic Director and Physiotherapist at Tweed Valley Physiotherapy. May 2016. 

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