When running on the level, muscles perform as much positive as negative external work. On a slope, the external positive and negative works performed are not equal. The present study is intended to analyse how the ratio between positive and negative work modifies the bouncing mechanism of running. Our goals are (i) to identify the changes in motion of the centre of mass of the body associated with the slope of the terrain and the speed of progression, (ii) to study the effect of these changes on the storage and release of elastic energy during contact and (iii) to propose a model that predicts the change in the bouncing mechanism with slope and speed. Therefore, the ground reaction forces were measured on ten subjects running on an instrumented treadmill at different slopes (from −9° to +9°) and different speeds (between 2.2 and 5.6 m s−1). The movements of the centre of mass of the body and its external mechanical energy were then evaluated. Our results suggest that the increase in the muscular power is contained (1) on a positive slope: by decreasing the step period and the downward movements of the body, and by increasing the duration of the push, and (2) on a negative slope: by increasing the step period and the duration of the brake, and by decreasing the upward movement of the body. Finally the spring-mass model of running was adapted to take into account the energy added or dissipated each step on a slope.
ACCEPTED MANUSCRIPT
RESEARCH ARTICLE|
01 January 2016
The rebound of the body during uphill and downhill running at different speeds
A. H. Dewolf,
A. H. Dewolf
1
Laboratory of biomechanics and Physiology of locomotion, Institute of NeuroScience , Université catholique de Louvain, Louvain-la-Neuve, Belgium
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L. E. Peñailillo,
L. E. Peñailillo
2
Exercise Science Laboratory, School of Kinesiology, Faculty of Medicine, Universidad Finis Terrae, Santiago, Chile
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P. A. Willems
P. A. Willems
*
1
Laboratory of biomechanics and Physiology of locomotion, Institute of NeuroScience , Université catholique de Louvain, Louvain-la-Neuve, Belgium
*Author for correspondence:
Faculté des Sciences de la Motricité, Université catholique de Louvain, Place P. de Coubertin, 1, B-1348 Louvain-la-Neuve
, Belgium
. e-mail: patrick.willems@uclouvain.be; tel: +32 10 47 44 32; fax: +32 10 47 31 06
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A. H. Dewolf
1
Laboratory of biomechanics and Physiology of locomotion, Institute of NeuroScience , Université catholique de Louvain, Louvain-la-Neuve, Belgium
L. E. Peñailillo
2
Exercise Science Laboratory, School of Kinesiology, Faculty of Medicine, Universidad Finis Terrae, Santiago, Chile
P. A. Willems
*
1
Laboratory of biomechanics and Physiology of locomotion, Institute of NeuroScience , Université catholique de Louvain, Louvain-la-Neuve, Belgium
*Author for correspondence:
Faculté des Sciences de la Motricité, Université catholique de Louvain, Place P. de Coubertin, 1, B-1348 Louvain-la-Neuve
, Belgium
. e-mail: patrick.willems@uclouvain.be; tel: +32 10 47 44 32; fax: +32 10 47 31 06
Received:
11 May 2016
Accepted:
14 May 2016
Online ISSN: 1477-9145
Print ISSN: 0022-0949
© 2016. Published by The Company of Biologists Ltd
2016
J Exp Biol jeb.142976.
Article history
Received:
11 May 2016
Accepted:
14 May 2016
Currently Viewing Accepted Manuscript - Newer Version Available
01 Aug 2016
Citation
A. H. Dewolf, L. E. Peñailillo, P. A. Willems; The rebound of the body during uphill and downhill running at different speeds. J Exp Biol 2016; jeb.142976. doi: https://doi.org/10.1242/jeb.142976
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