Why Do I Have Knee Pain? Complete Guide to Patellofemoral Pain Syndrome: Part 6 - Pain - FITNESS PAIN FREE

Why Do I Have Knee Pain? Complete Guide to Patellofemoral Pain Syndrome: Part 6 – Pain

Patellofemoral pain syndrome (PFPS) is the most common form of knee pain treated in physical therapy clinics.  I made this series to help people better understand this condition, why it occurs and how to fix it.

In case you missed it:

Today we’ll be discussing what happens after we develop PFPS and set the foundation for how we can start going about decreasing our knee pain.

So what happens after we get pain?

In the last article we explained how overuse of the PF joint can lead to pain.  Basically we exceed the PF joint’s capacity to tolerate stress and pain ensues.  I made a few graphs to help understand this.  Basically, before pain we can perform all types of movement without eliciting any pain.   
We have adequate capacity to handle all sorts of exercise.  Let’s say we go for a Spartan Race with our buddies and your knee starts hurting.  We have basically exceeded our knee’s current capacity for stress and now we have pain.

Now what ends up happening is that we can’t do as much as we could before without experiencing pain.  Maybe we can walk and perform stairs without pain but pretty much any lower body training in the gym hurts. In this example we can see that we cant even perform loaded squats without experiencing pain.  Our capacity has dropped, and with it our ability to perform the activities we love.

It makes sense, our bodies produce pain in order to protect us after injury (and to prevent future mistakes).  In my mind pain is basically our body’s way of telling us to “be careful not to do anything stupid”.  After an injury pain exists to keep us safe and to help us regulate the amount of activity we perform so the body can recover.  Pain kind of sounds like a good thing right?  Well, yes it is.  It’s important not just from a perspective of keeping us safe but also because it can be a good sign during our rehabilitation.  Let me explain further.

What’s important to understand is that what causes our body to heal is the same thing that causes injury in the first place.  This would be stress in the form of exercise.  

After injury we need to find the correct dosage of stress in order to make a positive adaptation and improve our knee’s “capacity” again following injury.  Stress from exercise helps to heal the PF joint but we need to have the correct dosage.

Now, if you have a headache and take 2 aspirin, the headache will probably go away.  We took the proper dosage.  If you have a headache and take the entire bottle of aspirin, you’re dead.  Wrong dosage.  The aspirin wasn’t the wrong choice, the dosage of aspirin was.

The same thing goes for rehabilitation of the PF joint.  We need to find the correct dosage of exercise to heal the joint.  We already spoke about how patellofemoral pain syndrome tends not to get better in time without intervention (24) and as we just noted toward, too much stress is obviously not good either.

What’s important to understand is that too much stress can end up making the situation worse.  However, not enough stress can be equally as bad.  Check out the graphs below to get a better grasp of this.  The “firing level” represents the athlete’s pain threshold.  All activities below the threshold do not elicit any pain.


In the first graphical representation we have an athlete who avoids everything that causes pain in the knee.  This would represent “not enough stress” to make a positive adaptation.  Our athlete isn’t applying enough stress to the PF joint to make progress with pain.

The second graphical representation depicts an athlete who tends to blow through their pain levels.  Over time, just like the athlete who does too little, the dosage of exercise is off and pain persists (and can worsen).  Again, the dosage is wrong.

In the third graph you can see the athlete works at their threshold of pain.  Over time the pain threshold gradually improves.  As the threshold improves our athlete works at a slightly higher intensity to reflect the improvements in threshold.  Over time this continues and our athlete gradually builds their capacity up again and can do more and more with diminishing levels of pain.

A key factor in this equation is that our athlete was working with some pain the entire time.  There’s quite a bit of research out there showing that working with some pain during rehabilitation exercise is ok and patients do tend to get better over time.  Working with some pain during exercise can actually result in faster short term improvements in pain compared to performing rehab exercises without any pain.  Maybe this is due to applying the proper dosage of stress to the PF joint.

Determining how much pain to work with is a very gray area and challenging for therapists and patients alike to determine just how much pain is ok to push through during physical therapy exercises.  Before attempting any therapy program of course you should have a conversation with your therapist / doctor to determine the appropriate dosage of exercise.  I wrote an in depth article on how I like figure this out.  Access the article by clicking on this link.  My basic principles for pain during physical therapy exercises are:

  • Pain should be minimal or at or below a 3/10 on a 0-10 pain scale during exercise
  • Pain levels should return to baseline following exercise and the following day
  • Pain and function should be improving on a weekly and monthly basis

If these requirements are not being fulfilled we need to change something, the dosage is off.  If we’re meeting these requirements, we’re on the right track.  It’s honestly an experimental process that we learn more and more about with the passage of time.  Keep in mind that applying rehabilitation exercise properly is like trying to hit a moving target.  Exercises difficulty will change over time based on how your body responds.

So to recap:

  • The PF joint’s capacity to handle stress decreases after an injury
  • Normal activities that used to be pain free now produce pain
  • Pain is a normal process designed to help protect the body and keep you safe in the future
  • Restoring knee capacity and eliminating pain revolves around properly dosing exercise
  • Stress in the form of exercise helps to reduce pain
  • Working with small levels of pain can be beneficial to help rehabilitate fully
  • How much pain you experience during and after exercise will help guide the intensity of exercise over time

Now that we’ve gone over what happens when we experience pain in the knee, it’s finally time to go over how to get out of pain!  In the next installment we go over a plan to get you out of pain.

Click HERE for Part 7:

Still pumped about knee pain,

Dan Pope DPT, OCS, CSCS, CF L1

Works Cited:

  1. Current Concepts and Treatment of Patellofemoral Compressive Issues IJSPT 2016 https://www.ncbi.nlm.nih.gov/pubmed/27904792
  2. Current Concepts in Biomechanical Interventions for Patellofemoral Pain IJSPT 2016 https://www.ncbi.nlm.nih.gov/pubmed/27904791
  3. Examination of the Patellofemoral Joint IJSPT 2016 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5095938/
  4. Biomechanics and pathomechanics of the Patellofemoral Joint IJSPT 2016 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5095937/
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  6. Tibiofemoral and Patellofemoral Mechanics are Altered at Small Knee Flexion Angles in People with Patellofemoral Pain https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3425715/
  7. Kay M Crossley, Marienke van Middelkoop, Michael J Callaghan, Natalie J Collins, Michael Skovdal Rathleff, Christian J Barton, 2016 Patellofemoral pain consensus statement from the 4th International Patellofemoral Pain Research Retreat, Manchester. Part 2: recommended physical interventions (exercise, taping, bracing, foot orthoses and combined interventions) BJSM http://bjsm.bmj.com/content/early/2016/05/31/bjsports-2016-096268
  8. Christian John Barton, Simon Lack, Steph Hemmings, Saad Tufail, Dylan Morrissey, The ‘Best Practice Guide to Conservative Management of Patellofemoral Pain’: incorporating level 1 evidence with expert clinical reasoning BJSM 2015http://bjsm.bmj.com/content/49/14/923#T
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  14. Trunk and lower extremity segment kinematics and their relationship to pain following movement instruction during a single-leg squat in females with dynamic knee valgus and patellofemoral pain. 2015 https://www.ncbi.nlm.nih.gov/pubmed/24836048
  15. The Basic Science of Articular Cartilage – Sports Health 2009 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3445147/
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  17. The Development and Application of an Injury Prediction Model for Noncontact, Soft-Tissue Injuries in Elite Collision Sport Athletes. (n.d.). Retrieved August 01, 2016, from https://www.researchgate.net/publication/46288877_The_Development_and_Application_of_an_Injury_Prediction_Model_for_Noncontact_Soft-Tissue_Injuries_in_Elite_Collision_Sport_Athletes
  18. Relationship Between Training Load and Injury in Professional Rugby League https://www.researchgate.net/profile/Tim_Gabbett/publication/49775412_Relationship_between_training_load_and_injury_in_professional_rugby_league_players/links/551894590cf2d70ee27b41ad.pdf
  19. Training and game loads and injury risk in elite Australian footballers. (n.d.). Retrieved from https://www.researchgate.net/profile/Brent_Rogalski/publication/234699103_Training_and_game_loads_and_injury_risk_in_elite_Australian_footballers/links/53dadd6b0cf2a19eee8b3f9f.pdf
  20. The acute:chronic workload ratio predicts injury: high chronic workload may decrease injury risk in elite rugby league players. Retrieved from http://bjsm.bmj.com/content/50/4/231 Hulin, Gabbett, Lawson, Caputi, Sampson
  21. Prospective Predictors of Patellofemoral Pain Syndrome: A Systematic Review With Meta-analysis. Sports Health 2012
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  23. Is body mass index associated with patellofemoral pain and patellofemoral osteoarthritis? A systematic review and meta-regression and analysis. BJSM 2017 https://www.ncbi.nlm.nih.gov/pubmed/27927675
  24. Is Knee Pain During Adolescence a Self-limiting Condition? Prognosis of Patellofemoral Pain and Other Types of Knee Pain. AJSM 2016 https://www.ncbi.nlm.nih.gov/pubmed/26792702
  25. The psychological features of patellofemoral pain: a systematic review. BJSM 2017 https://www.ncbi.nlm.nih.gov/pubmed/28320733
  26. The Association of Ankle Dorsiflexion Range of Motion With Hip and Knee Kinematics During the Lateral Step-down Test. JOSPT 2016
  27. The effect of reduced ankle dorsiflexion on lower extremity mechanics during landing: A systematic review Journal Sci Med Sport 2017 https://www.ncbi.nlm.nih.gov/pubmed/26117159
  28. Stress and Your Body: The Great Courses by Robert Sapolsky
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  30. Effectiveness of hip muscle strengthening in patellofemoral pain syndrome patients: a systematic review https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4518569/
  31. Exercise for treating patellofemoral pain syndrome: an abridged version of Cochrane systematic review. https://www.ncbi.nlm.nih.gov/pubmed/26158920 Cochrane 2016
  32. Differences in pressure pain threshold among men and women after foam rolling. https://www.ncbi.nlm.nih.gov/pubmed/29037655
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  35. Nonspecific Low Back Pain and Return to Work https://www.aafp.org/afp/2007/1115/p1497.html#sec-7
  36. Therapeutic Neuroscience Education – Adriaan Louw

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