Q-Angle, Segment Length, Quadriceps, and Knee Alignment in Soccer Players

Keywords

• Soccer
• Anthropometry
• Electromyography
• Quadriceps Muscle
• Biomechanical Phenomena

Lead sponsor

Suleyman Demirel University is the lead sponsor of 127 studies on the registry; 36 are open to participants now.

Study population

Groups and cohorts

• Group of footballers

  Football player group: One-time measurements were planned. For each player, measurements of the Q-angle, lower extremity segment lengths, surface electromyography, and dynamic knee alignment during a single-leg squat were planned for the dominant lower extremity.

  Other: Group 1

Interventions

• OtherGroup 1

  The study was designed to include individuals aged 18-35 who actively play football, voluntarily agreed to participate, had engaged in regular football training over the past six months, were able to perform a single-leg squat independently during the assessment, and had no acute musculoskeletal issues that could affect the measurements. All assessments for this group will be conducted by a doctor of physiotherapy. Plans were made to regularly record participation rates and measurements. For each player, measurements of the Q-angle, lower extremity segment lengths, surface electromyography, and dynamic knee alignment during a single-leg squat were planned for the dominant lower extremity.

Primary outcomes

1. Q angle

   Q-angle: With the subject in a supine position and the lower extremities in a neutral position, the angle formed by the lines connecting the anterior superior iliac spine (ASIS) to the center of the patella and the center of the patella to the tibial tuberosity will be recorded as the Q-angle using a universal goniometer. Three consecutive measurements will be performed on both extremities, and the mean of these measurements will be used in the analyses.

   Time frame: Baseline (Day 0)

Secondary outcomes

1. Lower extremity segment lengths

   Measurement of lower extremity segment lengths: The distance between the anterior superior iliac spine (ASIS) and the medial malleolus will be measured in centimeters with the subject in the supine position. Femur length will be measured in centimeters as the distance between the greater trochanter and the lateral condyle of the femur. Tibia length will be measured in centimeters as the distance between the lateral condyle of the femur and the lateral malleolus. A non-stretchable tape measure will be used for the measurements. Measurements for both extremities will be recorded separately, and right-left differences will be calculated. The femur/tibia ratio will be calculated by dividing the femur length by the tibia length. All measurements will be repeated once.

   Time frame: Baseline (Day 0)

2. Surface Electromyography Assessment:

   A 'Noraxon' device will be used for surface electromyography to assess quadriceps muscle activity. EMG activity will be recorded from the \*m. rectus femoris\* (RF), \*m. vastus medialis\* (VM), and \*m. vastus lateralis\* (VL) muscles on the dominant side. Electrode placement will adhere to the standards of the "Surface EMG for Non-Invasive Assessment of Muscles" (SENIAM) project. Electrodes will be positioned parallel to the direction of the muscle fibers: for the RF, at approximately 50% of the line between the ASIS and the patella; for the VM, at approximately 80% of the line between the ASIS and the reference point on the medial aspect of the knee joint space; and for the VL, at approximately two-thirds of the line between the ASIS and the lateral edge of the patella. Prior to electrode placement, body hair and dead skin will be removed using a razor and alcohol, and electrodes will be placed with a center-to-center distance of 20 mm. A BIOPAC MP150 system will be used for surface elec

   Time frame: Baseline (Day 0)

3. Dynamic Knee Alignment During Single-Leg Squat

   Participants will be instructed on the correct squatting and descent technique from a lateral view using an instructional video and verbal explanations. Before the test begins, participants will perform the movement approximately four times. For the test, kinesiology tape markers will be placed at the following reference points: the anterior superior iliac spine (ASIS), the midpoint of the patella, and the midpoint of the ankle (between the medial and lateral malleoli). Three trials will be performed for each lower extremity, with a two-minute rest period between trials. Participants will be asked to perform a single-leg squat, flexing the knee to approximately 60°. During the test, participants will be required to stand barefoot on a marked line, keep the non-tested knee flexed at approximately 90°, cross their arms over their chest, and maintain a forward gaze. A maximum of 5 seconds will be allowed to complete the test, which will commence upon the researcher's command. A trial wil

   Time frame: Baseline (Day 0)

Individual participant data

Plan to share: No — The data for objectives of the research will be compared after they are received.