Influence of Training Surface and Mechanical Load on the Prevalence of Patellofemoral Pain in Recreational Runners

Influence of Training Surface and Mechanical Load on the Prevalence of Patellofemoral Pain in Recreational Runners: A Cross-Sectional Cohort Study

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.

Study Overview

• Status: Active, not recruiting
• Conditions: Patello Femoral Pain Syndrome
• Intervention / Treatment: Other: Runner sample

• Study Type: Observational
• Enrollment (Estimated): 134

Contacts and Locations

Study Locations

• Spain
  • Principality of Asturias
    • Oviedo, Principality of Asturias, Spain, 33006
      • Universidad de Oviedo

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Adult non-professional / recreational runners who train regularly and perform the majority of their training on asphalt, trail, or mountain terrain.

Description

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)

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Observational group; Non-professional / recreational adult runners who train regularly and perform the majority of their training on asphalt, trail, or mountain terrain.	Other: Runner 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Measurement of patellofemoral pain over the previous three months.	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	Screening visit

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Measurement of functional severity of patellofemoral pain	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.	Screening visit
Measurement of terrain exposure (previous 3 months)	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.	Screening visit
Measurement of weekly positive and negative elevation gain	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.	Screening visit
Measurement of the percentage of downhill kilometers	If mountain terrain is predominant, an additional item will be included to capture the percentage of kilometers run on downhills with a gradient ≥6%.	Screening visit
Measurement of training intensity and internal load (previous 4 weeks)	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).	Screening visit
Measurement of training volume over the previous 4 weeks	This variable will include weekly running distance (kilometers), training frequency (number of sessions per week), and session duration (minutes per session).	Screening visit
Measurement of mean running pace over the previous 4 weeks	This variable will be recorded as minutes per kilometer (min/km).	Screening visit

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Measurement of age	This potential confounding or moderating variable will be measured in years.	Screening visit
Measurement of gender	This potential confounding or moderating variable will be recorded as a dichotomous variable (female/male).	Screening visit
Measurement of body mass index	This potential confounding or moderating variable will be calculated as kg/m².	Screening visit
Measurement of previous knee pain or injury	This potential confounding or moderating variable will be assessed as a dichotomous variable by asking: "Have you experienced knee pain or injury in the past 24 months?" (yes/no).	Screening visit
Mesurement of a running experience	This potential confounding or moderating variable will be measured as the number of years of running.	Screening visit
Measurement of training frequency	This potential confounding or moderating variable will be recorded as the number of training sessions per week.	Screening visit
Measurement of accumulated elevation gain	This potential confounding or moderating variable will be measured as the total elevation gain per week.	Screening visit
Measurement of lower-limb strength training	This potential confounding or moderating variable will be measured as the number of days per week dedicated to lower-limb and core strength exercises.	Screening visit
Measurement of footwear rotation	This potential confounding or moderating variable will be assessed as a dichotomous variable indicating the use of two or more pairs of running shoes in rotation (yes/no).	Screening visit

Collaborators and Investigators

• Sponsor: University of Oviedo
• Investigators: Principal Investigator: Rubén Cuesta-Barriuso, PhD, Universidad de Oviedo

Study record dates

Study Major Dates

• Study Start (Actual): February 12, 2026
• Primary Completion (Actual): April 3, 2026
• Study Completion (Estimated): May 11, 2026

Study Registration Dates

• First Submitted: February 6, 2026
• First Submitted That Met QC Criteria: February 6, 2026
• First Posted (Actual): February 13, 2026

Study Record Updates

• Last Update Posted (Actual): May 1, 2026
• Last Update Submitted That Met QC Criteria: April 27, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Exercise; Epidemiology; Running; Workload; Patellofemoral Pain Syndrome; Surfaces
• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Joint Diseases; Behavior; Patellofemoral Pain Syndrome; Motor Activity
• Other Study ID Numbers: Correc

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No