Effect of Corrective Exercises on Posture, Upper Extremity Muscle Activity, and Shoulder Kinematics in Male Handball Players With Upper Cross Syndrome
Authors:   Department of Biomechanics and Sport Injuries, Faculty of Physical Education and Sport Science, Kharazmi University, Tehran, Iran., Sakinepoor Ainollah , Hadadnezhad Malihe ,   Department of Biomechanics and Sport Injuries, Faculty of Physical Education and Sport Science, Kharazmi University, Tehran, Iran., Shojaedin Seyed Sadredin ,   Department of Biomechanics and Sport Injuries, Faculty of Physical Education and Sport Science, Kharazmi University, Tehran, Iran., Letafatkar Amir ,   Department of Biomechanics and Sport Injuries, Faculty of Physical Education and Sport Science, Kharazmi University, Tehran, Iran., Khaleghi Tazji Mehdi ,   Department of Biomechanics and Sport Injuries, Faculty of Physical Education and Sport Science, Kharazmi University, Tehran, Iran.
Published: May 2024

Background and Aims Abnormal posture and alterations in movement and muscle activity patterns have been reported in people with upper cross syndrome (UCS). These changes can lead to imbalance in muscle activation, altered movement patterns, and biomechanical changes. The present study aims to investigate the effect of corrective exercises on posture, upper extremity muscle activity, and shoulder kinematics in male handball players with UCS. Methods This quasi-experimental study was conducted on 30 male handball players with UCS who were randomly divided into exercise (n=15) and control (n=15) groups. The variables including upper extremity muscle activation patterns, shoulder kinematics, forward head posture, forward shoulder posture, and kyphosis were evaluated before and after intervention. Should kinematics and activation patterns of upper extremity muscles (supraspinatus, lumbar erector spinae, upper trapezius, middle trapezius, latissimus dorsi, pectoralis major) were recorded using electromyography and motion analyzer. The angles of forward head and forward shoulder were assessed using photographic method taken from lateral view, and Kyphosis angle was measured using a flexible ruler before and after exercises. The exercise group performed the comprehensive corrective exercises for 8 weeks (3 sessions per week), but the control group did not receive any intervention. To analyze the data, two-way analysis of variance and Bonferroni test were used. The significant level was set at 0.05. Results Forward head posture (P=0.001), forward shoulder posture (P=0.003), and kyphosis (P=0.002) showed significant improvements in the exercise group compared to the control group from pretest to post-test phase. In the preparatory and throw phases (slow and fast throwing), higher activities of supraspinatus, lumbar erector spinae, upper trapezius, middle trapezius, latissimus dorsi, and pectoralis major were observed in the exercise group compared to the control group (P=0.05). Moreover, in the preparatory and throw phases, higher range of motion of shoulder flexion, forward flexion of shoulder, internal rotation of shoulder, external rotation of shoulder, and shoulder abduction were observed in the exercise group compared to the control group (P=0.05). Conclusion Corrective exercises can significantly alter shoulder kinematics and upper extremity muscle activity patterns in male handball players with UCS, which can be used in future studies to prevent UCS in handball players during throwing the ball.