The Effectiveness of an Exercise Program on Scapulohumeral Rhythm, Range of Motion, and Stability in Young Female Handball Players

Scapular upward rotation is assessed with the Digital Inclinometer (BASELINE 12-1057) in a seated position to minimize compensatory movements of the trunk and lower extremities. The first measurement is taken at baseline (0° of shoulder flexion), followed by additional measurements at 30°, 60°, 90°, and 120° of shoulder flexion. Each position is held for 10-15 seconds to ensure stable measurement conditions. Measurements are repeated three times and the average is used for analysis. The assessment will be performed on both the dominant and non-dominant upper limb to evaluate movement symmetry. Data will be recorded manually by a research assistant to reduce the risk of reading errors and to ensure measurement accuracy. Statistical analysis will be performed to determine the scapulohumeral rhythm across different ranges of motion and to identify potential movement asymmetries.

Isometric strength assessment of the shoulder girdle muscles will be conducted using the Lafayette Hand-Held Dynamometer (HHD). For the rotator muscles, measurements will be performed in the prone position with the shoulder abducted to 90° and the elbow flexed to 90°, with the forearm hanging freely over the edge of the examination table. This setup will be used for both internal and external rotation strength assessments. Results are expressed in Newtons (N) or normalized to body weight as Newtons per kilogram (N/kg).

The Y-Balance Upper Quarter Test (YBT-UQ) is used to assess upper extremity stability and reach performance. The test requires the participant to maintain a single-arm support position while the opposite arm performs reaching movements in three directions: anterior (forward), inferolateral (diagonally opposite the supporting hand), and superolateral (diagonally toward the supporting hand).

Each reach is measured in centimeters, and the final score for each direction is calculated as the average of three trials. The test will be performed on both upper limbs and arm length will be included in the analysis to ensure standardized results. Results will be reported in centimeters, "cm", and Upper Limb Length % (standardized by upper limb length).

Range of motion is measured for internal and external rotation of the shoulder. The participant is positioned in the prone position with the shoulder abducted to 90 degrees and the elbow flexed to 90 degrees, allowing the forearm to hang freely over the edge of the examination table. The starting position (0 degrees) is defined as the forearm being vertically aligned. Results are presented in degre

Two strips of tape will be placed on the floor 90 cm apart. Participants will be instructed to assume a push-up position and perform as many hand touches as possible on each strip within 15 seconds. The examiner will count the number of touches.

Three trials will be conducted, and the final score will be calculated as the average number of touches across all three trials. A 45-second rest period will be provided between each trial.

The CKCUEST score and CKCUEST power will be calculated using the following formulas:

• Score = Average number of touches on CKCUEST / height (m)
• Power = 68% of body weight (kg) × Average number of touches on CKCUEST