Mechanics of standing and crouching sprint starts.
The aim of this study was to compare the kinetic and kinematic parameters of standing and crouch sprint starts. Parallel starts (PS), false starts (FS), jump starts (JS) and crouch starts (3PS) were compared. Eighteen participants performed each start on a force plate and six infrared cameras captured the three-dimensional coordinates of 36 retro-reflective markers. Performance during a five-metre sprint (T5m) was analysed. Duration of the start phase (Tstart), mean values of horizontal and total ground reaction forces (GRFs) (Fx_meanand Ftot_mean), ratio of force (RF), maximal power (Pmax) and kinetic energy (KE) of each limb were calculated. Significant differences were found for T5m, Tstart, KE, Pmax, Fx_mean, Ftot_meanand RF for the crouch start compared to the other starts (P ≤ 0.05). Significant correlations were found between T5mand Tstart(r = 0.59; P ≤ 0.001), and T5mand Pmax, Fx_meanand RF (-0.73 ≤ r ≤ -0.61; P ≤ 0.001). To conclude, the crouch start resulted in the best performance because Tstartwas shorter, producing greater Pmax, Fx_meanwith a more forward orientation of the resultant force. Greater KE of the trunk in each start condition demonstrated the role of the trunk in generating forward translation of the centre of mass (CM).
a UFRSTAPS - Centre de recherche sur le sport et le mouvement - EA 2931 , Université de Paris Ouest Nanterre La Défense , Nanterre , France.
Jean
J
Slawinski
b ESO Paris Research, Ecole Supérieure d'Ostéopathie , Champs-sur-Marne , France.
Nicolas
N
Houel
c Willy Taillard Laboratory of Kinesiology , Geneva University Hospitals and Geneva University , Geneva , Switzerland.
Alice
A
Bonnefoy-Mazure
a UFRSTAPS - Centre de recherche sur le sport et le mouvement - EA 2931 , Université de Paris Ouest Nanterre La Défense , Nanterre , France.
Kevin
K
Lissajoux
d Luxembourg Institute of Health , Competence Centre in Methodology and Statistics , Luxembourg , Grand-Duchy of Luxembourg.
Valery
V
Bocquet
a UFRSTAPS - Centre de recherche sur le sport et le mouvement - EA 2931 , Université de Paris Ouest Nanterre La Défense , Nanterre , France.
Nicolas
N
Termoz
D000054:Acceleration; D054874:Athletic Performance / Q000502:physiology*; D001696:Biomechanical Phenomena; D006801:Humans; D035002:Lower Extremity / Q000502:physiology; D011187:Posture / Q000502:physiology*; D012420:Running / Q000502:physiology*; D013996:Time and Motion Studies; D060726:Torso / Q000502:physiology; D034941:Upper Extremity / Q000502:physiology; D055815:Young Adult
Ratio of force; Sprint; biomechanics; centre of mass; start