Eur J Appl Physiol DOI 10.1007/s00421-013-2805-6
Original Article
The mechanics of jumping over an obstacle during running: a comparison between athletes trained to hurdling and recreational runners G. Mauroy · B. Schepens · P. A. Willems
Received: 14 December 2012 / Accepted: 16 December 2013 © Springer-Verlag Berlin Heidelberg 2014
Abstract Purpose This study compares the mechanism of running in trained athletes (TA) experienced in hurdling and in recreational runners (RR), as they approach and jump over an obstacle. Methods The movements of the centre of mass of the body (COM), the external muscular work (Wext) and the leg-spring stiffness (kleg) were evaluated in athletes approaching an obstacle at 18 km h−1, from the ground reaction forces (measured by force-platforms) and the orientation of the lower-limb segments (measured by camera). These results were compared to those obtained in RR. Results Two steps before the obstacle, kleg is reduced by 10–20 %; so, the COM is lowered and accelerated forward. During the step preceding the obstacle, kleg is increased by 40–60 %; so the COM is raised and accelerated upwards, whereas its forward velocity is reduced. This change in the running pattern is similar to the one observed in RR while leaping an obstacle. However, in TA, the change in stiffness is less pronounced. As a result, the orientation of the velocity vector at the beginning of the aerial phase over the obstacle is more horizontal than in RR, which involves a 10–20 % greater horizontal velocity and a 40–60 % smaller vertical excursion of the COM when crossing the obstacle;
Communicated by Jean-René Lacour. Electronic supplementary material The online version of this article (doi:10.1007/s00421-013-2805-6) contains supplementary material, which is available to authorized users. G. Mauroy · B. Schepens · P. A. Willems (*) Laboratoire de physiologie et biomécanique de la locomotion, Institute of NeuroScience, Université catholique de Louvain, Place Pierre de Coubertin, 1, 1348 Louvain‑la‑Neuve, Belgium e-mail: [email protected]
subsequently, Wext during contact before the obstacle is 10– 20 % less. Conclusion Athletes use the same mechanisms as nonspecialists to cross an obstacle. However, athletes adapt the mechanism of jumping to reduce the loss in the velocity of progression when crossing an obstacle. Keywords Running · Jumping · Hurdle · Mechanical work · Leg stiffness
Introduction In a recent study, Mauroy et al. (2012) have analysed a situation that often occurs during cross-country running or jogging: a person moving at a slow or intermediate speed comes across an obstacle, jumps over it and continues to run at the same pace. To leap across the obstacle, the runner increases the vertical velocity (Vv) of the centre of mass of the body (COM) at takeoff to lengthen the duration and amplitude of the aerial phase. This increase in Vv is done at the expense of the horizontal velocity (Vf) of the COM. When a recreational runner crosses a
Original Article
The mechanics of jumping over an obstacle during running: a comparison between athletes trained to hurdling and recreational runners G. Mauroy · B. Schepens · P. A. Willems
Received: 14 December 2012 / Accepted: 16 December 2013 © Springer-Verlag Berlin Heidelberg 2014
Abstract Purpose This study compares the mechanism of running in trained athletes (TA) experienced in hurdling and in recreational runners (RR), as they approach and jump over an obstacle. Methods The movements of the centre of mass of the body (COM), the external muscular work (Wext) and the leg-spring stiffness (kleg) were evaluated in athletes approaching an obstacle at 18 km h−1, from the ground reaction forces (measured by force-platforms) and the orientation of the lower-limb segments (measured by camera). These results were compared to those obtained in RR. Results Two steps before the obstacle, kleg is reduced by 10–20 %; so, the COM is lowered and accelerated forward. During the step preceding the obstacle, kleg is increased by 40–60 %; so the COM is raised and accelerated upwards, whereas its forward velocity is reduced. This change in the running pattern is similar to the one observed in RR while leaping an obstacle. However, in TA, the change in stiffness is less pronounced. As a result, the orientation of the velocity vector at the beginning of the aerial phase over the obstacle is more horizontal than in RR, which involves a 10–20 % greater horizontal velocity and a 40–60 % smaller vertical excursion of the COM when crossing the obstacle;
Communicated by Jean-René Lacour. Electronic supplementary material The online version of this article (doi:10.1007/s00421-013-2805-6) contains supplementary material, which is available to authorized users. G. Mauroy · B. Schepens · P. A. Willems (*) Laboratoire de physiologie et biomécanique de la locomotion, Institute of NeuroScience, Université catholique de Louvain, Place Pierre de Coubertin, 1, 1348 Louvain‑la‑Neuve, Belgium e-mail: [email protected]
subsequently, Wext during contact before the obstacle is 10– 20 % less. Conclusion Athletes use the same mechanisms as nonspecialists to cross an obstacle. However, athletes adapt the mechanism of jumping to reduce the loss in the velocity of progression when crossing an obstacle. Keywords Running · Jumping · Hurdle · Mechanical work · Leg stiffness
Introduction In a recent study, Mauroy et al. (2012) have analysed a situation that often occurs during cross-country running or jogging: a person moving at a slow or intermediate speed comes across an obstacle, jumps over it and continues to run at the same pace. To leap across the obstacle, the runner increases the vertical velocity (Vv) of the centre of mass of the body (COM) at takeoff to lengthen the duration and amplitude of the aerial phase. This increase in Vv is done at the expense of the horizontal velocity (Vf) of the COM. When a recreational runner crosses a
