Frontal Plane Knee Projection Angle and Functional Performance in Adolescent Female Volleyball Players

NCT07711236 | Completed

• 1 other identifier: FPPATTADF1
• Study Type: observational
• Target: 70
• Locations: 1 country
• Sites: 1

Brief Summary

This observational study aims to examine the relationship between frontal plane knee projection angle, dynamic balance, agility performance, and ankle dorsiflexion mobility in adolescent female volleyball players. Frontal plane knee projection angle will be assessed during a single-leg squat using two-dimensional video analysis. Dynamic balance will be evaluated with the Lower Quarter Y-Balance Test, agility with the T-Test, and ankle dorsiflexion mobility with the Weight-Bearing Lunge Test. All measurements will be completed in a single session under standardized field conditions, and no intervention or experimental treatment will be applied. By investigating how frontal plane knee alignment is associated with functional performance measures, this study may help improve the understanding of biomechanical factors related to movement quality and injury risk in adolescent female volleyball players.

Conditions

Dynamic Knee Valgus; Agility; Dynamic Balance; Ankle Dorsiflexion

Keywords

frontal plane knee projection angle; dynamic balance; agility; ankle dorsiflexion; volleyball

Outcome Measures

Primary Outcomes (1)

• Frontal Plane Projection Angle

  Frontal plane projection angle (FPPA) was assessed using SparkMotion software. FPPA was calculated from the angle between a line from the anterior superior iliac spine (ASIS) to the midpoint of the patella and a line from the patellar midpoint to the midpoint between the medial and lateral malleoli; this value was subtracted from 360° to obtain FPPA. Values ≥195° were descriptively classified as increased FPPA. Frontal-plane video was recorded using an iPad mounted on a tripod positioned 3 m from the participant and 1 m above the ground. Participants performed a single-leg squat with arms crossed over the chest at a metronome-paced tempo (2 s descent, 2 s ascent). FPPA was measured at the deepest squat position reached while maintaining balance. After 3 practice trials, 5 consecutive recorded squats were performed, and the third trial was used for analysis.

  At a single assesment sessiomn

Secondary Outcomes (3)

• Y - Balance Test

  At a single assesment session

• T - Test

  At a single assesment session

• Weight - Bearing Lunge Test

  At a single assesment session

Study Arms (1)

Adolescent Female Volleyball Players

Adolescent female volleyball players who were regularly training at AB Volleyball Academy and participated in this observational study. All participants completed biomechanical and functional assessments in a single session, including frontal plane knee projection angle during a single-leg squat, dynamic balance, agility, and ankle dorsiflexion mobility measurements. No intervention or experimental treatment was applied.

Eligibility Criteria

• Age: 10 Years - 19 Years
• Sex: female
• Healthy Volunteers: Yes
• Age Groups: Child (0-17), Adult (18-64)
• Sampling Method: Non-Probability Sample

Study Population

The study population consisted of adolescent female volleyball players aged 10 to 19 years who were regularly training at least 3 days per week at AB Volleyball Academy in Izmir, Türkiye. Only participants who had reached menarche and met all eligibility criteria were included.

You may qualify if:

• Being female and between 10 and 19 years of age
• Participating in regular volleyball training at least 3 days per week
• Having reached menarche

You may not qualify if:

• Having sustained a lower extremity injury within the previous 6 months
• Having a history of lower extremity surgery
• Using medication that could affect balance, attention, or physical performance
• Having a neurological, orthopedic, or systemic condition that could affect performance

Sponsors & Collaborators

• Sinop University: lead

Study Sites (1)

AB Volleyball Academy

Izmir, Ödemiş, 35750, Turkey (Türkiye)

Location

Related Publications (2)

• Chalabiyev N, Basaran S, Deniz V, Adas U, Sariyildiz A. Beyond muscle activation: the role of biomechanical properties of muscles in determining dynamic knee valgus in female volleyball players. BMC Sports Sci Med Rehabil. 2026 Apr 16;18(1):249. doi: 10.1186/s13102-026-01681-1.

  PMID: 41987323 BACKGROUND

• Sassi LB, Miguel AC, Serafim TT, de Menezes FS, Martins TB, Okubo R. Understanding ACL injuries in volleyball: a systematic review of epidemiology and risk factors. Front Sports Act Living. 2025 Dec 8;7:1675136. doi: 10.3389/fspor.2025.1675136. eCollection 2025.

  PMID: 41438279 BACKGROUND

Study Design

• Study Type: observational
• Observational Model: OTHER
• Time Perspective: CROSS SECTIONAL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: DR.

Study Record Dates

• First Submitted: July 14, 2026
• First Posted: July 17, 2026
• Study Start: March 1, 2026
• Primary Completion: March 3, 2026
• Study Completion: July 1, 2026
• Last Updated: July 17, 2026

Record last verified: 2026-07

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)