Dynamic Knee ValgusFPPA-DBANCT07711236
Frontal Plane Knee Projection Angle and Functional Performance in Adolescent Female Volleyball Players
An observational study of Dynamic Knee Valgus and Agility, run by Sinop University at 1 site in Turkey (Türkiye).
Trial 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. Read more about this study
- Who is it for?
- Ages 10 to 19 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Dynamic Knee Valgus, Agility, Dynamic Balance
- How many people
- 70 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 26 Jun 2026to 20 Jul 2026
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 10 to 19 years
- Women only
- Healthy volunteers accepted
- Child, Adult
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.
Who may be able to join
- Being female and between 10 and 19 years of age
- Participating in regular volleyball training at least 3 days per week
- Having reached menarche
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Investigation of the Relationship Between Frontal Plane Knee Projection Angle and Dynamic Balance, Agility, and Ankle Dorsiflexion Mobility in Adolescent Female Volleyball Players
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.
Read the detailed description
This observational, cross-sectional study aims to investigate the relationship between frontal plane knee projection angle (FPPA), dynamic balance, agility performance, and ankle dorsiflexion mobility in adolescent female volleyball players. Volleyball is a sport that requires repeated jumping, landing, lateral movements, and rapid changes of direction, which place considerable biomechanical demands on the lower extremities. In adolescent female athletes, lower-limb movement patterns may be influenced by growth, maturation, and neuromuscular control, making this population important for biomechanical assessment.
The primary study variable will be frontal plane knee projection angle, assessed during a single-leg squat using two-dimensional video analysis. Secondary measures will include dynamic balance assessed with the Lower Quarter Y-Balance Test, agility assessed with the T-Test, and ankle dorsiflexion mobility assessed with the Weight-Bearing Lunge Test. All assessments will be completed in a single session under standardized field conditions. No intervention, treatment, or experimental exercise program will be applied.
The study is designed to explore whether frontal plane knee alignment is associated with functional performance measures in adolescent female volleyball players. A better understanding of these relationships may contribute to the identification of biomechanical characteristics related to lower-extremity movement quality and potential injury risk in this population.
- Conditions
- Dynamic Knee Valgus, Agility, Dynamic Balance, Ankle Dorsiflexion
- Keywords
- frontal plane knee projection angle, dynamic balance, agility, ankle dorsiflexion, volleyball
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| 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. |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: Day 1
Secondary outcomes (3)
Y - Balance Test
Dynamic balance was assessed using the Lower Quarter Y-Balance Test (YBT-LQ). This standardized test evaluates reach distance in the anterior, posteromedial, and posterolateral directions while maintaining single-leg stance. Reach distances were recorded to the nearest 0.5 cm using the Y Balance Test kit. Before testing, leg length was measured from the anterior superior iliac spine (ASIS) to the distal tip of the medial malleolus, and results were normalized to leg length. Participants completed 6 practice trials before testing, followed by 3 valid trials in each direction. Invalid trials were repeated, and the mean of the 3 valid trials for each direction was used for analysis. The composite score was calculated by dividing the sum of the 3 reach distances by 3 times leg length and multiplying by 100.
Measured: Day 1
T - Test
Agility was assessed using the T-Test. The test course was set up in a T shape with 4 cones: cone A was positioned 9.14 m from the center cone B, and cones C and D were placed 4.57 m to the left and right of cone B. Participants started at cone A, sprinted to cone B, shuffled laterally to touch cone C, then shuffled to touch cone D, returned to cone B, and backpedaled to cone A to complete the test. Time was recorded using a photocell timing system. After 2 familiarization trials, participants performed 3 valid trials with 3 minutes of rest between trials, and the best time was used for analysis.
Measured: Day 1
Weight - Bearing Lunge Test
nkle dorsiflexion mobility was assessed using the Weight-Bearing Lunge Test (WBLT). Participants were positioned facing a wall in a tandem stance, with the tested foot aligned perpendicular to the wall and the non-tested rear heel lifted. They were instructed to place their hands on the wall and move the front knee toward it while keeping the tested heel in contact with the ground. The foot was moved away from the wall in 1 cm increments until the maximum distance at which the knee could still touch the wall without heel lift was identified. The farthest valid distance between the great toe and the wall was measured in centimeters. Three valid trials were recorded for each lower extremity, and the mean value was used for analysis. Trials with heel lift, marked lower-extremity compensations, or loss of proper test position were repeated.
Measured: Day 1
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted17 Jul 2026
- Study start26 Jun 2026
- Primary completion20 Jul 2026
- Study completion20 Jul 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Dynamic Knee ValgusStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Other
- Time perspective
- Cross-sectional
- Enrolment
- 70 participants (actual)
Sponsor and investigators
- Lead sponsor
- Sinop University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, SEFA HAKTAN HATIK, Sinop University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07711236
- Sponsor's protocol ID
- FPPATTADF1
- Acronym
- FPPA-DBA
- Status last verified
- Oct 2026
- First submitted
- 14 Jul 2026
- Last updated
- 16 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
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.
PubMed 41987323Sassi 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.
PubMed 41438279
Study at a glance
From the registry record, last updated by the sponsor on 16 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Investigation of the Relationship Between Frontal Plane Knee Projection Angle and Dynamic Balance, Agility, and Ankle Dorsiflexion Mobility in Adolescent Female Volleyball Players
- ClinicalTrials.gov ID
- NCT07711236
- Acronym / sponsor ID
- FPPA-DBA / FPPATTADF1
- Conditions
- Dynamic Knee Valgus, Agility, Dynamic Balance, Ankle Dorsiflexion
- Keywords
- frontal plane knee projection angle, dynamic balance, agility, ankle dorsiflexion, volleyball
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 70 participants (actual)
- Lead sponsor
- Sinop UniversityUniversity, hospital or other
- Study start
- 26 Jun 2026 (actual)
- Primary completion
- 20 Jul 2026 (actual)
- Study completion
- 20 Jul 2026 (actual)
- First posted
- 17 Jul 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
This observational, cross-sectional study aims to investigate the relationship between frontal plane knee projection angle (FPPA), dynamic balance, agility performance, and ankle dorsiflexion mobility in adolescent female volleyball players. Volleyball is a sport that requires repeated jumping, landing, lateral movements, and rapid changes of direction, which place considerable biomechanical demands on the lower extremities. In adolescent female athletes, lower-limb movement patterns may be influenced by growth, maturation, and neuromuscular control, making this population important for biomechanical assessment.
The primary study variable will be frontal plane knee projection angle, assessed during a single-leg squat using two-dimensional video analysis. Secondary measures will include dynamic balance assessed with the Lower Quarter Y-Balance Test, agility assessed with the T-Test, and ankle dorsiflexion mobility assessed with the Weight-Bearing Lunge Test. All assessments will be completed in a single session under standardized field conditions. No intervention, treatment, or experimental exercise program will be applied.
The study is designed to explore whether frontal plane knee alignment is associated with functional performance measures in adolescent female volleyball players. A better understanding of these relationships may contribute to the identification of biomechanical characteristics related to lower-extremity movement quality and potential injury risk in this population.
Study design
- Observational model
- Other
- Time perspective
- Cross-sectional
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| 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. |
Who may qualify
- Ages
- 10 to 19 years
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Child, Adult
- 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.
Key inclusion criteria (3 listed)
- Being female and between 10 and 19 years of age
- Participating in regular volleyball training at least 3 days per week
- Having reached menarche
Key exclusion criteria (4 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Frontal Plane Projection Angle
Time frame: Day 1
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.
3 secondary outcomes
Y - Balance Test
Time frame: Day 1
T - Test
Time frame: Day 1
Weight - Bearing Lunge Test
Time frame: Day 1
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 16 Oct 2026.
- Background: PubMed 41987323Chalabiyev 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.
- Background: PubMed 41438279Sassi 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.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Dynamic Knee Valgus and Agility, run by Sinop University at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 16 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Frontal Plane Projection Angle (time frame: Day 1). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07711236, which also lists 2 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 16 Oct 2026.