Genu Varum, Change of Direction, and Reactive Agility in Youth Football Players

Does Genu Varum Influence Change of Direction and Reactive Agility Performance in Youth Football Players?

The goal of this observational study is to compare change-of-direction (COD) and reactive agility (RA) performance between football players with and without genu varum and to examine whether lower-limb alignment is associated with these performance measures.

The main questions it aims to answer are:

1. Do football players with and without genu varum differ in COD and RA performance?
2. Is lower-limb alignment associated with COD and RA performance in football players with and without genu varum?

Football players with and without genu varum will undergo assessments of lower-limb alignment, COD performance, and RA performance. The study will compare performance between the two groups and examine the relationship between lower-limb alignment and performance measures.

Study Overview

• Status: Completed
• Conditions: Genu Varum

• Study Type: Observational
• Enrollment (Actual): 34

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Antalya, Turkey (Türkiye)
    • Akdeniz University

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Probability Sample

Study Population

The study population consisted of male youth football players recruited from the academy of a professional football club based in Antalya, Türkiye. The football club competes in the Turkish Süper Lig, the highest tier of professional football in Türkiye.

Description

Inclusion Criteria:

• At least five years of football experience
• Participation in football training at least five days per week
• Voluntary participation in the study

Exclusion Criteria:

• History of lower extremity surgery
• Current musculoskeletal injury affecting performance

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Genu Varum Group; Football players with genu varum who will be assessed for lower-limb alignment, change-of-direction performance, and reactive agility performance.
Control Group; Football players without genu varum who will be assessed for lower-limb alignment, change-of-direction performance, and reactive agility performance.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change-of-direction performance	Change-of-direction performance will be assessed using the SpeedCourt system (Globalspeed GmbH, Hemsbach, Germany). The test consists of a 14.5-m running course with four changes of direction. Performance will be evaluated based on total completion time, with lower times indicating better change-of-direction performance.	at basline
Reactive agility performance	Reactive agility performance will be assessed using the SpeedCourt system (Globalspeed GmbH, Hemsbach, Germany). Participants will respond as quickly and accurately as possible to randomly presented visual stimuli and perform the required directional movements. Performance will be evaluated based on total completion time, with lower times indicating better reactive agility performance.	at basline

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Intercondylar distance and intermalleolar distance	Lower-limb alignment will be assessed by measuring intercondylar distance (ICD) and intermalleolar distance (IMD) in centimeters. ICD will be measured as the distance between the medial femoral condyles, and IMD as the distance between the medial malleoli, using a standardized measurement procedure.	at basline

Collaborators and Investigators

• Sponsor: Akdeniz University

Study record dates

Study Major Dates

• Study Start (Actual): March 1, 2025
• Primary Completion (Actual): June 1, 2025
• Study Completion (Actual): June 12, 2025

Study Registration Dates

• First Submitted: August 28, 2026
• First Submitted That Met QC Criteria: August 28, 2026
• First Posted (Actual): September 1, 2026

Study Record Updates

• Last Update Posted (Actual): September 3, 2026
• Last Update Submitted That Met QC Criteria: September 2, 2026
• Last Verified: August 1, 2026

More Information

Terms related to this study

• Keywords: Soccer players; Football players; Genu varum; Lower extremity alignment; Lower-limb alignment; Change of direction; Knee alignment
• Additional Relevant MeSH Terms: Bone Diseases; Musculoskeletal Diseases; Genu Varum
• Other Study ID Numbers: 2025-89

Plan for Individual participant data (IPD)

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