title: From block clearance to sprint running: characteristics underlying an effective transition.
abstract: The aim of this study was to characterize the specifics of the sprint technique during the transition from start block into sprint running in well-trained sprinters. Twenty-one sprinters (11 men and 10 women), equipped with 74 spherical reflective markers, executed an explosive start action. An opto-electronic motion analysis system consisting of 12 MX3 cameras (250 Hz; 325,000 pixels) and two Kistler force plates (1000 Hz) was used to collect the three-dimensional (3D) marker trajectories and ground reaction forces (Nexus, Vicon). The 3D kinematics, joint kinetics, and power were calculated (Opensim) and were time normalized to 100% from the first action after gunshot until the end of second stance after block clearance (Matlab). The results showed that during the first stance, power generation at the knee plays a significant role in obtaining an effective transition, representing 31% of power generation in the lower limb, in the absence of preceding power absorption. Furthermore, the sprinter actively searches a more forward leaning position to maximize horizontal velocity. Since success during sprinting from the second stance onwards involves high hip and ankle activation, the above-mentioned three characteristics are specific skills required to successfully conclude the transition from start block into sprint running.
authors.affiliation: Department of Kinesiology, Faculty of Kinesiology and Rehabilitation Sciences, Katholieke Universiteit Leuven, Leuven, Belgium.
authors.forename: Sofie
authors.initials: S
authors.lastname: Debaere
authors.forename: Christoph
authors.initials: C
authors.lastname: Delecluse
authors.forename: Dirk
authors.initials: D
authors.lastname: Aerenhouts
authors.forename: Friso
authors.initials: F
authors.lastname: Hagman
authors.forename: Ilse
authors.initials: I
authors.lastname: Jonkers
mesh_terms: D000328:Adult; D000843:Ankle Joint / Q000502:physiology*; D054874:Athletic Performance / Q000592:standards*; D001696:Biomechanical Phenomena; D005260:Female; D057918:Fiducial Markers; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D053580:Muscle Strength / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology; D012420:Running / Q000502:physiology*; D055815:Young Adult