Patello Femoral Pain Syndrome
Conditions
Keywords
Patellofemoral Pain Syndrome, Running, Surfaces, Exercise, Workload, Epidemiology
Brief summary
Background. Patellofemoral pain (PFP) is one of the most common causes of knee pain in recreational runners and is exacerbated by activities that load the patellofemoral joint. Although biomechanical differences between running surfaces and elevation profiles have been documented, the influence of terrain type and training load on PFP in non-professional runners remains poorly defined. Objective. To examine the association between predominant training terrain and the presence of PFP in non-professional runners, and to describe its functional severity. Secondarily, to analyze the relationship between terrain exposure, elevation, training load and volume with PFP, as well as the potential influence of previous knee history and footwear rotation. Methods. An observational, analytical, cross-sectional study conducted through an online survey targeting recreational runners. The primary outcome will be the presence of patellofemoral pain, defined according to the 2016 International Consensus, and functional severity will be assessed using the Spanish-validated Kujala Anterior Knee Pain Scale. Exposures will include the percentage of kilometers run on each terrain type, positive and negative elevation gain, internal load (session rating of perceived exertion × duration), training volume, and running pace. Potential confounders will include age, sex, body mass index, running experience, training frequency, previous knee history, lower-limb strength, accumulated elevation gain, and footwear rotation. Descriptive analyses and logistic regression models will be performed to identify independent associations. Expected results. To estimate the prevalence of PFP in recreational runners, identify terrain- and load-related factors associated with its occurrence, and define a predictive model to inform prevention strategies and training planning.
Interventions
OTHERRunner sample
Runners with lower or different exposure to these factors: other predominant terrain types (e.g., asphalt or trail), lower accumulated elevation gain, and/or lower levels of internal load and training volume.
Sponsors
University of Oviedo
Study design
Observational model
COHORT
Time perspective
CROSS_SECTIONAL
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* Participants aged 18 years or older. * Recreational (non-professional) runners. * Have run regularly over the previous 3 months (at least once per week). * Are able to report their predominant training terrain (asphalt, trail, or mountain). * Have or do not have patellofemoral pain. * Have provided written informed consent.
Exclusion criteria
* Have had a complete cessation of running for ≥4 weeks within the previous 3 months. * Have undergone major knee or ankle surgery within the past year. * Have a diagnosis of conditions that clearly alter gait or running pattern. * Present severe knee disorders that preclude accurate assessment of patellofemoral pain. * Have incomplete questionnaires for essential variables (terrain type, patellofemoral pain, AKPS, training load, or training volume)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Measurement of patellofemoral pain over the previous three months. | Screening visit | This variable will be defined according to the International Consensus on Patellofemoral Pain. Participants will be classified as positive cases if they report anterior or retropatellar knee pain in the previous three months, exacerbated by at least one weight-bearing, knee-flexion activity (e.g., running, stair ambulation, slopes, or squatting), with a duration of ≥4 weeks or ≥2 episodes during that period |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Measurement of functional severity of patellofemoral pain | Screening visit | Functional severity will be assessed using the Spanish-validated version of the Kujala Anterior Knee Pain Scale. This is a condition-specific 13-item questionnaire that evaluates functional limitations, symptoms, and the ability to perform knee-loading activities. Total scores range from 0 to 100, with higher scores indicating better function and, therefore, lower severity. |
| Measurement of terrain exposure (previous 3 months) | Screening visit | This variable will capture the type of terrain on which the runner habitually trains (asphalt, trail, and mountain). Participants will report the approximate percentage of total kilometers completed on asphalt, trail, and mountain terrain over the previous three months. |
| Measurement of weekly positive and negative elevation gain | Screening visit | This variable will be recorded as an average value (meters per week, or normalized as meters per 10 km), given that eccentric loading and patellofemoral joint stress increase substantially during prolonged downhill running. |
| Measurement of the percentage of downhill kilometers | Screening visit | If mountain terrain is predominant, an additional item will be included to capture the percentage of kilometers run on downhills with a gradient ≥6%. |
| Measurement of training intensity and internal load (previous 4 weeks) | Screening visit | Training intensity will be assessed using Foster's session Rating of Perceived Exertion (sRPE), based on the Borg CR-10 scale (0-10). Participants will report their mean perceived exertion for each session type (e.g., easy runs, intervals, hill sessions) over the previous four weeks. Weekly internal load will be calculated by multiplying the sRPE value by session duration (minutes). |
| Measurement of training volume over the previous 4 weeks | Screening visit | This variable will include weekly running distance (kilometers), training frequency (number of sessions per week), and session duration (minutes per session). |
| Measurement of mean running pace over the previous 4 weeks | Screening visit | This variable will be recorded as minutes per kilometer (min/km). |
Countries
Spain
Contacts
PRINCIPAL_INVESTIGATORRubén Cuesta-Barriuso, PhD
Universidad de Oviedo
Outcome results
None listed