Anterior Knee Pain Syndrome, Patellofemoral Pain Syndrome
Conditions
Keywords
Dynamic Q Angle, Core Endurance, Lower Extremity Function, Sports-Specific Biomechanics, Elite Athletes, Adolescent Sports Performance
Brief summary
This observational, cross-sectional study aimed to compare dynamic Q-angle, trunk/core endurance, and lower-extremity flexibility between elite adolescent female and male sprinters with and without patellofemoral pain syndrome (PFPS). Participants were classified according to sex and PFPS status. Dynamic Q-angle was assessed during a standardized step-down task, trunk endurance was evaluated using McGill flexion, extension, and lateral endurance tests, and lower-extremity flexibility was assessed using the Straight Leg Raise, Modified Thomas, and Ober tests. The study also examined whether sex and PFPS status were independently associated with dynamic Q-angle. No therapeutic or experimental intervention was administered.
Detailed description
Patellofemoral pain syndrome is a common musculoskeletal condition in adolescent athletes and may be associated with altered frontal-plane knee alignment, reduced proximal trunk control, and lower-extremity flexibility impairments. Sprint athletes are exposed to repetitive high-load and high-velocity movement patterns that require coordinated control of the trunk, pelvis, and lower extremities. However, sex-related differences in the biomechanical profile of adolescent sprinters with PFPS remain insufficiently understood. This study was designed as an observational, cross-sectional, sex-based comparative investigation involving elite adolescent sprinters aged 15 to 17 years. A total of 150 athletes were enrolled. Three participants had incomplete assessment data and were excluded from the final analysis, resulting in 147 participants with complete data. Participants were classified into four groups according to sex and PFPS status: female sprinters without pain, female sprinters with PFPS, male sprinters without pain, and male sprinters with PFPS. PFPS status was determined through clinical assessment by a sports medicine physician. The diagnostic assessment included anterior knee pain symptoms, clinical patellofemoral tests, the Anterior Knee Pain Scale, and the Visual Analog Scale. Control participants had no current anterior knee pain or clinical findings consistent with PFPS. Dynamic Q-angle was assessed during a standardized step-down task using a two-dimensional mobile goniometric application. Anatomical markers were placed over the anterior superior iliac spine, patellar center, and tibial tuberosity. Two repetitions were recorded, and the mean value was used for analysis. Trunk/core endurance was assessed using the McGill trunk flexion, trunk extension, and lateral endurance tests. Lower-extremity flexibility was evaluated using the Straight Leg Raise test for hamstring flexibility, the Modified Thomas test for hip-flexor flexibility, and the Ober test for iliotibial band and tensor fascia latae tightness. Body composition and relevant demographic and training characteristics were also recorded. The primary objective was to compare dynamic Q-angle between participants according to sex and PFPS status. Secondary objectives were to compare trunk endurance and lower-extremity flexibility outcomes and to identify independent factors associated with dynamic Q-angle. All measurements were obtained during a single assessment period, and no therapeutic, exercise, pharmacological, or experimental intervention was administered.
Interventions
OTHERPatellofemoral Pain Syndrome Status
Participants were classified as having patellofemoral pain syndrome (PFPS) or not having PFPS based on a clinical assessment performed by a sports medicine physician. PFPS classification was based on anterior knee pain symptoms, positive patellofemoral clinical tests, an Anterior Knee Pain Scale score below 80, and a Visual Analog Scale pain score of at least 3. Biological sex was used as an additional grouping factor. No therapeutic, exercise, pharmacological, or experimental intervention was administered.
Sponsors
Eastern Mediterranean University
Study design
Observational model
CASE_CONTROL
Time perspective
CROSS_SECTIONAL
Eligibility
Sex/Gender
ALL
Age
15 Years to 17 Years
Healthy volunteers
Yes
Inclusion criteria
Female or male adolescent elite sprinters aged 15-17 years Minimum of two years of regular athletic training Participation in athletic training at least four days per week Possession of a valid track and field license Active participation in sprint events at the national or international level Ability to complete all clinical and biomechanical assessments Written informed consent from the participant and a parent or legal guardian PFPS Group-Specific Criteria: Diagnosis of patellofemoral pain syndrome by a sports medicine physician Anterior knee pain localized to the patellofemoral region Positive patellar compression and grind test Anterior Knee Pain Scale score below 80 Visual Analog Scale pain score of at least 3 Control Group-Specific Criteria: No current anterior knee pain No clinical findings consistent with patellofemoral pain syndrome
Exclusion criteria
History of lower-extremity surgery Acute lower-extremity injury within the previous six months Notable musculoskeletal deformity Arthritis or chronic pain affecting the knee, hip, or ankle Neurological or systemic disease that could affect movement or physical performance Inability to complete the assessments because of excessive pain or insufficient cooperation Incomplete assessment data
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Dynamic Q-Angle During the Step-Down Test (degrees) | Baseline (single assessment at study enrollment) | Dynamic Q-angle was assessed during a standardized step-down task from a 16-cm platform using the DrGoniometer mobile application. Anatomical markers were placed over the anterior superior iliac spine, center of the patella, and tibial tuberosity. Two repetitions were recorded in the frontal plane, and the mean angle was used for analysis. In participants with PFPS, the symptomatic extremity was assessed; in participants without PFPS, the corresponding matched extremity was used. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Trunk/Core Endurance Test Duration (seconds) | Baseline (single assessment at study enrollment) | Trunk/core endurance was assessed using the McGill trunk flexion, trunk extension, and lateral plank endurance tests. The duration for which each standardized test position was maintained was recorded in seconds. Flexion, extension, and lateral endurance outcomes were analyzed separately; no composite score was calculated. |
| Hamstring Flexibility - Straight Leg Raise Angle (degrees) | Baseline (single assessment at study enrollment) | Hamstring flexibility was assessed using the Straight Leg Raise test. The assessed lower extremity was passively raised while the knee was maintained in extension, and the maximum hip flexion angle was recorded in degrees. Three measurements were performed, and the mean value was used for analysis. |
| Hip Flexor Flexibility - Modified Thomas Test Angle (degrees) | Baseline (single assessment at study enrollment) | Hip flexor flexibility was assessed using the Modified Thomas test. The non-assessed lower extremity was maintained in hip flexion while the hip angle of the assessed extremity was measured in degrees. Three measurements were performed, and the mean value was used for analysis. |
| Iliotibial Band and Tensor Fasciae Latae Flexibility - Ober Test Angle (degrees) | Baseline (single assessment at study enrollment) | Iliotibial band and tensor fasciae latae flexibility was assessed using the Ober test. The assessed lower extremity was positioned in hip extension and abduction and then allowed to move into adduction. The resulting thigh-drop angle was recorded in degrees. Three measurements were performed, and the mean value was used for analysis. |
Countries
Turkey (Türkiye)
Contacts
STUDY_CHAIRburcin ugur tosun
Ministry of Youth and Sports, Olympic Preparation Center, Adana, Türkiye
Outcome results
None listed