Akademik Veri Yönetim Sistemi
Motor control, cilt.27, sa.2, ss.228-241, 2022 (SCI-Expanded)
Instep kick is one of the most effective kicking techniques in soccer. Lower extremity muscles and
joints play a crucial role during instep kick. However, external and internal focus and their effect
on the muscles are still ambiguous. In this study, 13 male adolescent soccer players were included
and aimed to hit the targets in internal and external focus conditions. Lower extremity muscle
activations were measured with sEMG and kinematics were measured with a high-speed video
camera. Muscle activations and movement latencies were analyzed in four different phases
(backswing, leg cocking, acceleration, follow-through) of kicking. While 10 out of 13 participants
kicked accurately in internal focus, only 5 out of 13 in external focus kicked accurately.
Gastrocnemius muscle activations increased significantly in external focus in all phases except
acceleration. Movement latencies were found 0.07±0.002 sec for accurate and 0.05±0.004 sec for
inaccurate kicks in external focus. A correlation has been found between accuracy and movement
latency in EF(R=0.67). Our results suggest that novices cannot yet coordinate their muscles in
external focus, co-contraction ratio increases. Therefore, training strategies that aim to reduce the
co-contraction ratio can help the athlete increase performance through better motor coordination.
Moreover, better motor coordination may be beneficial in preventing injuries (joint stiffness, etc.)
caused by increased co-contraction ratio