Rhythm-Based Stabilization Training in Video Gamers

This is a low-cost test that evaluates the functional performance and stability of the upper extremity in a closed kinetic chain. For the test, the participant assumes a push-up position with their hands placed 90 cm apart; men use the full position, while women use a modified (knees on the ground) position. The test is based on the principle of touching one hand to the other as quickly as possible within 15 seconds and returning to the starting position, and the total number of touches is recorded as a score. The participant performs three trials separated by 45-second rest periods.

Reaction Time is used to assess upper extremity reaction time and motor speed in athletes and young adults. In this study, a visual-cognitive reaction technology device (Blazepod) that has been shown to have high reliability will be used. Participants will be asked to turn off the light pods, which are randomly placed on the ground, by touching them with their dominant hand as quickly as possible when they are turned on. During the application, each participant will perform 5 trials separated by a 5-second rest period. Measurements will be recorded in milliseconds (ms), excluding the fastest and slowest values, and the average reaction time will be recorded.

This is a static test used to assess scapular asymmetry and medial-lateral inferior angle displacement. The measurement is taken by measuring the distance between the inferior angle of the scapula and the corresponding thoracic spine process with a tape measure while the participant is standing upright. The test is performed in three different arm positions:

• Arm in neutral position, free at the sides.
• Arm in 45° abduction, hands on hips.
• Arm in 90° abduction, hands above the head (or thumbs pointing upwards). A difference of more than 1.5 cm between the right and left sides is considered clinically significant scapular asymmetry.

This test is performed in a standing position to measure the endurance of the scapular stabilizing muscles. The participant stabilizes their scapula in a neutral position with their shoulder and elbow flexed at 90°, and maintains a 1 kg load determined by a dynamometer. The test continues until the participant can no longer maintain the position or the load. The measurement is repeated twice, and the longest time achieved is recorded in seconds.

It is a tool developed to assess upper extremity performance and overall upper trunk stability at the limits. The test aims to identify movement limitations and asymmetries in pre-sports and rehabilitation screening. The participant assumes a push-up position with one hand placed on a support platform and attempts to reach the furthest possible distance with the other hand in 3 different directions: medial (inner), inferolateral (downward-outward), and superolateral (upward-outward). Attempts must be completed without losing balance or moving the standing hand.

Joint range of motion is a crucial component of upper extremity functional performance. This study will evaluate wrist flexion/extension and radial/ulnar deviation movements, as well as finger flexion/extension movements. Measurements will be taken using the HandROM Measurement System, which has been shown to be a reliable alternative to traditional goniometers. The system will allow for objective analysis of upper extremity functions, scapular control, and hand performance.

This test will be used to evaluate upper extremity explosive power. Participants position themselves upright in a chair without armrests, with their ankles, knees, and hips at a 90-degree angle. They are then asked to grasp a 3 kg medicine ball with both hands and throw it forward overhead without leaning forward or flexing their elbows. The point where the ball first touches the ground is measured from the starting point and recorded in centimeters.

The Visual Analog Scale will be used to assess the subjective intensity of pain experienced by the participant. This scale is a validated self-assessment tool for acute and chronic pain, rated from 0 ("no pain") to 10 ("unbearable pain"). Participants will be asked to rate the severity of their pain, particularly in the shoulder and upper extremity region, within this range.

The Shoulder Pain and Disability Index is a 13-item self-report questionnaire developed to assess the severity of shoulder pain and associated functional limitations in patients.The questionnaire includes a Pain subsection consisting of 5 items and a Disability subsection consisting of 8 items. Participants are asked to rate each item on a numerical rating scale (NRS) from 0 to 10. The validity and reliability of the questionnaire in Turkish have been proven. The final result is calculated as a percentage out of 100; a higher score indicates greater pain and disability.