Runners knee - A Practical, Evidence-Based approach to Recovery

Introduction

Patellofemoral Pain Syndrome (PFPS), commonly known as Runner’s Knee, is a leading cause of anterior knee pain, affecting both runners and non-runners. Traditionally, rehabilitation has been broken down into phases, but in clinical practice, these phases are not rigid—rather, they blend together based on the individual’s presentation and pain tolerance.

Instead of following a strict step-by-step process, I take a combined approach, incorporating:

• Exercises that build strength without aggravating the PFJ
• Exercises that progressively reintroduce load to the knee
• Running modifications that allow continued training without increasing symptoms

By managing load, mechanics, and symptom tolerance, we can keep people active while minimizing pain and setbacks.

Building Strength Without Aggravating the PFJ

A key principle early on is loading the muscles while avoiding excessive patellofemoral joint stress.

Blood Flow Restriction (BFR) Training

• Why It Works:
  • BFR allows muscle growth and strength gains at 20-30% of 1RM, reducing joint stress (Hughes et al., 2017).
  • Enhances quadriceps activation without requiring heavy loads.
  • Allows for early strength maintenance without worsening pain.

• Seated Knee Extensions combined with BFR: 90-45 degree range ONLY to begin with
• Pain-Free Squats or leg press combined with BFR: 0-45 degree range
• Straight Leg Raises combined with BFR: (progressing from lying → sitting → standing)

At the same time, I begin incorporating low-load exercises that start exposing the joint to controlled forces (Powers et al. 2014).

Reintroducing the PFJ to Load Gradually

While minimising pain is important, at some point the knee needs to relearn how to handle stress. I often introduce low-load, joint-loading exercises alongside general strength work.

Progressive Strength Loading

1. Split Squats & Bulgarian Split Squats

   • Load the quads and glutes in functional positions.
   • Modify knee travel based on pain tolerance (Silbernagel model: keep pain ≤ 3-4/10).

2. Step-Downs & Decline Squats

   • Step-downs challenge eccentric control while gradually increasing knee flexion angles.
   • Decline squats increase patellar tendon load, progressing toward full function.

3. Plyometrics & Landing Mechanics

   • Countermovement jumps (CMJ)
   • Box jumps & drop landings (progressively increasing eccentric load)
   • Lateral bounds & single-leg hops

Rather than waiting for full symptom resolution before introducing these exercises, I often layer them in as tolerated, ensuring pain is controlled.

Keeping Runners Running: Modifications for Training

For runners, completely stopping running is rarely necessary. Instead, modifying their training allows them to continue while minimising PFJ stress.

Key Adjustments for Runners

1. Reduce Running Speed

   • Faster speeds increase knee joint forces.
   • Slowing down reduces the impact on the patellofemoral joint.

2. Shorten Stride Length & Increase Cadence

   • Studies show that increasing cadence (steps per minute) by 5-10% reduces patellofemoral joint loading (Lenhart et al., 2014).
   • Cadence target: 170-180 steps per minute (varies per individual).

3. Reduce Overall Volume

   • Instead of eliminating running, I often reduce mileage while keeping runners moving.
   • Example: Shift to 2 mins ON / 1 min OFF intervals to control load exposure.

4. Taping for Short-Term Pain Relief

   • McConnell Taping: Alters patellar tracking and can provide short-term relief.
   • Kinesiology Tape (KT Tape): Less restrictive but may help with proprioception. Sports Tape have a useful video tutorial that can be found here - https://sporttape.co.uk/pages/how-to-kinesiology-tape-runners-knee?srsltid=AfmBOopKWMMigpAaKxT3y7_iTG9eymNMSVqfenAG8dXlj6VSM9Yg0mgF
   • While taping doesn’t “fix” PFPS, it can be useful in making running more tolerable while addressing underlying issues.

This multifaceted approach allows runners to maintain training adaptations while minimising aggravation of symptoms.

Other things to consider

• Often runners undergo a running gait analysis which often leads to advice regarding their running mechanics or a recommendation of a specific running shoe. Be cautious of changing from what feels comfortable and natural. While these new shoes may be good for you in theory, it's likely that your soft tissues have adapted to withstand the current loads your running style and shoes place on them. If you then change this, you are increasing the loading demands on certain tissues and structures which can lead to pain and injury. For example, if you run in a relatively flat shoe and then change to a shoe that has a heel drop height of greater than 6mm, it will reduce the load through your achilles but increase the loading demands on your knees. Just something to bear in mind!
• How strong is your hip and ankle? Weakness here can increase the workload on your knees. Have you a previous ankle injury that was never fully rehabilitated?

Blending All Three Phases in Real Life

Even though I’ve broken this process into three phases, in practice, they overlap significantly.

•  I do NOT wait until strength is fully restored before reintroducing load to the knee.
•  I do NOT wait until the knee is "perfect" before keeping a runner running.
•  I often combine strength exercises, early joint loading, and running modifications at the same time.

For example, in a single session, I might:

• Use BFR training to maintain quad strength without PFJ stress
• Introduce step-downs or split squats to progressively load the knee
• Tape the knee and adjust cadence & stride length so the runner can keep training pain-free

This layered, individualized approach ensures runners, gym-goers, and athletes stay active without unnecessary time off.

Final Thoughts

• BFR training helps maintain strength without overloading the knee.
• Gradual strength progression through split squats, step-downs, and plyometrics builds joint resilience.
• Running modifications (shorter stride, higher cadence, gradual volume increases) allow early return to running without excessive joint stress.
• Taping can provide short-term relief, helping runners stay active while addressing underlying issues.
• Rather than rigid phases, real-world rehab blends these elements together based on symptoms and goals.

By managing load exposure, biomechanics, and pain tolerance, we can keep individuals active while minimising pain and long-term disruptions.

References

Barton, C. J., Lack, S., Hemmings, S., Tufail, S., & Morrissey, D. (2015). The ‘Best Practice Guide to Conservative Management of Patellofemoral Pain’: incorporating level 1 evidence with expert clinical reasoning.British Journal of Sports Medicine, 49(14), 923-934.

Hughes, L., Paton, B., Rosenblatt, B., Gissane, C., & Patterson, S. D. (2017). Blood flow restriction training in clinical musculoskeletal rehabilitation: a systematic review and meta-analysis. British Journal of Sports Medicine, 51(13), 1003-1011.

Korakakis, V., Whiteley, R., & Giakas, G. (2018). Low-load resistance training with blood flow restriction decreases anterior knee pain more than traditional resistance training: a randomized controlled trial. Physical Therapy in Sport, 29, 39-45.

Lenhart, R. L., Thelen, D. G., Wille, C. M., Chumanov, E. S., & Heiderscheit, B. C. (2014). Increasing running step rate reduces patellofemoral joint forces. Medicine & Science in Sports & Exercise, 46(3), 557-564.