title: Kinematics analyses related to stretch-shortening cycle during soccer instep kicking after different acute stretching.
abstract: The purpose of this study was to examine the effects of static and dynamic stretching within a preexercise warm-up on angular velocity of knee joint, deepest knee flexion (DKF), and duration of eccentric and concentric contractions, which are relative to the stretch-shortening cycle (SSC) during instep kicking in professional soccer players. The kicking motions of dominant legs were captured from 18 Olympic professional male soccer players (height: 180.38 ± 7.34 cm; weight: 69.77 ± 9.73 kg; age: 19.22 ± 1.83 years) using 4 digital video cameras at 50 Hz. There was a significant difference in the DKF after the dynamic stretching (-3.22 ± 3.10°) vs. static stretching (-0.18 ± 3.19°) relative to the no-stretching method with p < 0.001. Moreover, there was significant difference in eccentric duration after the dynamic stretching (0.006 ± 0.01 seconds) vs. static stretching (-0.003 ± 0.01 seconds) relative to the no-stretching method with p < 0.015. There was a significant difference in the concentric duration after the dynamic stretching (-0.007 ± 0.01 seconds) vs. static stretching (0.002 ± 0.01 seconds) relative to the no-stretching method with p < 0.001. There was also a significant difference in knee angular velocity after the dynamic stretching (4.08 ± 3.81 rad·s) vs. static stretching (-5.34 ± 4.40 rad·s) relative to the no-stretching method with p < 0.001. We concluded that dynamic stretching during warm-ups, as compared with static stretching, is probably the most effective way as preparation for the kinematics characteristics of soccer instep kick, which are relative to the SSC.
authors.affiliation: Department of Sports Biomechanics, Faculty of Physical Education and Sports Science, Shahid Bahonar University of Kerman, Kerman, Iran. amirikhorasani@uk.ac.ir
authors.forename: Mohammadtaghi
authors.initials: M
authors.lastname: Amiri-Khorasani
authors.forename: Reza
authors.initials: R
authors.lastname: Mohammadkazemi
authors.forename: Soodeh
authors.initials: S
authors.lastname: Sarafrazi
authors.forename: Shahin
authors.initials: S
authors.lastname: Riyahi-Malayeri
authors.forename: Vahid
authors.initials: V
authors.lastname: Sotoodeh
mesh_terms: D000293:Adolescent; D000328:Adult; D001696:Biomechanical Phenomena; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D009119:Muscle Contraction; D052580:Muscle Stretching Exercises / Q000379:methods*; D018482:Muscle, Skeletal / Q000502:physiology*; D059385:Plyometric Exercise; D012916:Soccer / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult