{"id":2050,"date":"2020-06-07T23:47:26","date_gmt":"2020-06-07T21:47:26","guid":{"rendered":"http:\/\/ecolesayu.deuxspirales.fr\/?p=2050"},"modified":"2020-06-28T15:39:54","modified_gmt":"2020-06-28T13:39:54","slug":"biomecanique-du-deplacement","status":"publish","type":"post","link":"https:\/\/ecolesayu.deuxspirales.fr\/index.php\/2020\/06\/07\/biomecanique-du-deplacement\/","title":{"rendered":"Biom\u00e9canique du d\u00e9placement"},"content":{"rendered":"<p>[et_pb_section admin_label=\u00a0\u00bbsection\u00a0\u00bb][et_pb_row admin_label=\u00a0\u00bbrow\u00a0\u00bb make_fullwidth=\u00a0\u00bboff\u00a0\u00bb use_custom_width=\u00a0\u00bboff\u00a0\u00bb width_unit=\u00a0\u00bbon\u00a0\u00bb use_custom_gutter=\u00a0\u00bboff\u00a0\u00bb custom_padding=\u00a0\u00bb10px|10px\u00a0\u00bb padding_mobile=\u00a0\u00bboff\u00a0\u00bb allow_player_pause=\u00a0\u00bboff\u00a0\u00bb parallax=\u00a0\u00bboff\u00a0\u00bb parallax_method=\u00a0\u00bboff\u00a0\u00bb make_equal=\u00a0\u00bboff\u00a0\u00bb column_padding_mobile=\u00a0\u00bbon\u00a0\u00bb][et_pb_column type=\u00a0\u00bb4_4&Prime;][et_pb_text admin_label=\u00a0\u00bbTexte\u00a0\u00bb]<\/p>\n<p>Nous allons poser les bases m\u00e9caniques du d\u00e9placement du corps dans l&rsquo;espace.<br \/>\nEn l&rsquo;absence de mouvement deux forces s\u2019appliquent au corps(fig.1) :<\/p>\n<p>[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row admin_label=\u00a0\u00bbLigne\u00a0\u00bb make_fullwidth=\u00a0\u00bboff\u00a0\u00bb use_custom_width=\u00a0\u00bboff\u00a0\u00bb width_unit=\u00a0\u00bbon\u00a0\u00bb use_custom_gutter=\u00a0\u00bboff\u00a0\u00bb custom_padding=\u00a0\u00bb10px|10px\u00a0\u00bb padding_mobile=\u00a0\u00bboff\u00a0\u00bb allow_player_pause=\u00a0\u00bboff\u00a0\u00bb parallax=\u00a0\u00bboff\u00a0\u00bb parallax_method=\u00a0\u00bboff\u00a0\u00bb make_equal=\u00a0\u00bboff\u00a0\u00bb column_padding_mobile=\u00a0\u00bbon\u00a0\u00bb][et_pb_column type=\u00a0\u00bb1_2&Prime;][et_pb_text admin_label=\u00a0\u00bbTexte\u00a0\u00bb background_layout=\u00a0\u00bblight\u00a0\u00bb text_orientation=\u00a0\u00bbleft\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb]<\/p>\n<ul>\n<li>Le poids (P) toujours vertical et orient\u00e9 vers le centre de la terre.<br \/>\nElle s\u2019applique au centre de gravit\u00e9 du corps qu&rsquo;on va fixer par convention en avant de la 4\u00e8me vert\u00e8bre Lombaire (L4). Sa valeur d\u00e9pend de la masse du corps concern\u00e9 et du champ de gravit\u00e9 \u00e0 l&rsquo;endroit \u00e9tudi\u00e9.<\/li>\n<li>La r\u00e9action (R) du sol. Force variable, elle d\u00e9pend des forces que le corps applique sur le sol.<br \/>\nElle s&rsquo;applique sur les points de contact du corps avec le sol (polygone de sustentation).<\/li>\n<\/ul>\n<p>[\/et_pb_text][\/et_pb_column][et_pb_column type=\u00a0\u00bb1_2&Prime;][et_pb_image admin_label=\u00a0\u00bbImage\u00a0\u00bb src=\u00a0\u00bbhttp:\/\/ecolesayu.deuxspirales.fr\/wp-content\/uploads\/2020\/06\/meca1.png\u00a0\u00bb alt=\u00a0\u00bbFigure 1 : Forces Appliqu\u00e9s au corps\u00a0\u00bb title_text=\u00a0\u00bbFigure 1 : Forces Appliqu\u00e9s au corps\u00a0\u00bb show_in_lightbox=\u00a0\u00bboff\u00a0\u00bb url_new_window=\u00a0\u00bboff\u00a0\u00bb animation=\u00a0\u00bboff\u00a0\u00bb sticky=\u00a0\u00bboff\u00a0\u00bb align=\u00a0\u00bbcenter\u00a0\u00bb force_fullwidth=\u00a0\u00bboff\u00a0\u00bb always_center_on_mobile=\u00a0\u00bbon\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb] [\/et_pb_image][et_pb_text admin_label=\u00a0\u00bbTexte\u00a0\u00bb background_layout=\u00a0\u00bblight\u00a0\u00bb text_orientation=\u00a0\u00bbleft\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb]<\/p>\n<p style=\"text-align: center;\">Figure 1 : Forces Appliqu\u00e9s au corps<\/p>\n<p>[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row admin_label=\u00a0\u00bbLigne\u00a0\u00bb make_fullwidth=\u00a0\u00bboff\u00a0\u00bb use_custom_width=\u00a0\u00bboff\u00a0\u00bb width_unit=\u00a0\u00bbon\u00a0\u00bb use_custom_gutter=\u00a0\u00bboff\u00a0\u00bb custom_padding=\u00a0\u00bb10px|10px\u00a0\u00bb padding_mobile=\u00a0\u00bboff\u00a0\u00bb allow_player_pause=\u00a0\u00bboff\u00a0\u00bb parallax=\u00a0\u00bboff\u00a0\u00bb parallax_method=\u00a0\u00bboff\u00a0\u00bb make_equal=\u00a0\u00bboff\u00a0\u00bb column_padding_mobile=\u00a0\u00bbon\u00a0\u00bb][et_pb_column type=\u00a0\u00bb4_4&Prime;][et_pb_text admin_label=\u00a0\u00bbTexte\u00a0\u00bb background_layout=\u00a0\u00bblight\u00a0\u00bb text_orientation=\u00a0\u00bbleft\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb]<\/p>\n<p>Pour mettre en mouvement le corps il faut r\u00e9ussir \u00e0 le faire acc\u00e9l\u00e9rer. On va utiliser les lois du mouvement de Newton. Elles nous disent : que pour un corps de masse m l&rsquo;acc\u00e9l\u00e9ration qu&rsquo;il subit est proportionnelle \u00e0 la r\u00e9sultante des forces qu&rsquo;il subit et inversement proportionnelle \u00e0 sa masse.<br \/>\nSur le dessin ci-dessus la somme de P et de R est \u00e9gale \u00e0 z\u00e9ro les deux forces s&rsquo;annulent On veut que la somme des forces aient une r\u00e9sultante non nulle pour permettre une acc\u00e9l\u00e9ration (a) et ainsi initier le mouvement(fig2).<\/p>\n<p>[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row admin_label=\u00a0\u00bbLigne\u00a0\u00bb make_fullwidth=\u00a0\u00bboff\u00a0\u00bb use_custom_width=\u00a0\u00bboff\u00a0\u00bb width_unit=\u00a0\u00bbon\u00a0\u00bb use_custom_gutter=\u00a0\u00bboff\u00a0\u00bb custom_padding=\u00a0\u00bb10px|10px\u00a0\u00bb padding_mobile=\u00a0\u00bboff\u00a0\u00bb allow_player_pause=\u00a0\u00bboff\u00a0\u00bb parallax=\u00a0\u00bboff\u00a0\u00bb parallax_method=\u00a0\u00bboff\u00a0\u00bb make_equal=\u00a0\u00bboff\u00a0\u00bb column_padding_mobile=\u00a0\u00bbon\u00a0\u00bb][et_pb_column type=\u00a0\u00bb1_2&Prime;][et_pb_text admin_label=\u00a0\u00bbTexte\u00a0\u00bb background_layout=\u00a0\u00bblight\u00a0\u00bb text_orientation=\u00a0\u00bbleft\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb]<\/p>\n<ul>\n<li>On ne peut pas modifier la masse du corps donc P est constant.<\/li>\n<li>On ne peut agir que sur R. Par l&rsquo;action des muscles on peut r\u00e9duire ou augmenter la force que l&rsquo;on applique sur le sol, ce qui va modifier la force r\u00e9sultante du sol sur nous(la r\u00e9action R). On peut aussi modifier son point d&rsquo;application en changeant nos appui.<\/li>\n<\/ul>\n<p>[\/et_pb_text][\/et_pb_column][et_pb_column type=\u00a0\u00bb1_2&Prime;][et_pb_image admin_label=\u00a0\u00bbImage\u00a0\u00bb src=\u00a0\u00bbhttp:\/\/ecolesayu.deuxspirales.fr\/wp-content\/uploads\/2020\/06\/meca2.png\u00a0\u00bb alt=\u00a0\u00bbFigure 2:R\u00e9sultante de la somme des forces\u00a0\u00bb title_text=\u00a0\u00bbFigure 2:R\u00e9sultante de la somme des forces\u00a0\u00bb show_in_lightbox=\u00a0\u00bboff\u00a0\u00bb url_new_window=\u00a0\u00bboff\u00a0\u00bb animation=\u00a0\u00bboff\u00a0\u00bb sticky=\u00a0\u00bboff\u00a0\u00bb align=\u00a0\u00bbcenter\u00a0\u00bb force_fullwidth=\u00a0\u00bboff\u00a0\u00bb always_center_on_mobile=\u00a0\u00bbon\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb] [\/et_pb_image][et_pb_text admin_label=\u00a0\u00bbTexte\u00a0\u00bb background_layout=\u00a0\u00bblight\u00a0\u00bb text_orientation=\u00a0\u00bbleft\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb]<\/p>\n<p style=\"text-align: center;\">Figure 2:R\u00e9sultante de la somme des forces<\/p>\n<p>[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row admin_label=\u00a0\u00bbLigne\u00a0\u00bb make_fullwidth=\u00a0\u00bboff\u00a0\u00bb use_custom_width=\u00a0\u00bboff\u00a0\u00bb width_unit=\u00a0\u00bbon\u00a0\u00bb use_custom_gutter=\u00a0\u00bboff\u00a0\u00bb custom_padding=\u00a0\u00bb10px|10px\u00a0\u00bb padding_mobile=\u00a0\u00bboff\u00a0\u00bb allow_player_pause=\u00a0\u00bboff\u00a0\u00bb parallax=\u00a0\u00bboff\u00a0\u00bb parallax_method=\u00a0\u00bboff\u00a0\u00bb make_equal=\u00a0\u00bboff\u00a0\u00bb column_padding_mobile=\u00a0\u00bbon\u00a0\u00bb][et_pb_column type=\u00a0\u00bb4_4&Prime;][et_pb_text admin_label=\u00a0\u00bbTexte\u00a0\u00bb background_layout=\u00a0\u00bblight\u00a0\u00bb text_orientation=\u00a0\u00bbleft\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb]<\/p>\n<p><strong>DEPLACER LE CENTRE DE GRAVITE VERS L&rsquo;AVANT<\/strong><br \/>\nPour avancer il va falloir faire incliner la R\u00e9action du sol vers l&rsquo;avant. Pour cela on va par l&rsquo;action musculaire changer les points d&rsquo;appuis et cr\u00e9er une force horizontale dirig\u00e9e vers l&rsquo;arri\u00e8re(Fig 3). Le point d&rsquo;appui va \u00eatre post\u00e9rioris\u00e9 par l&rsquo;action du muscle Droit ant\u00e9rieur. La force horizontale est engendr\u00e9e par les muscles Fessiers et les muscles Ischio-jambier(fig 4).<\/p>\n<p>[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row admin_label=\u00a0\u00bbLigne\u00a0\u00bb make_fullwidth=\u00a0\u00bboff\u00a0\u00bb use_custom_width=\u00a0\u00bboff\u00a0\u00bb width_unit=\u00a0\u00bbon\u00a0\u00bb use_custom_gutter=\u00a0\u00bboff\u00a0\u00bb custom_padding=\u00a0\u00bb10px|10px\u00a0\u00bb padding_mobile=\u00a0\u00bboff\u00a0\u00bb allow_player_pause=\u00a0\u00bboff\u00a0\u00bb parallax=\u00a0\u00bboff\u00a0\u00bb parallax_method=\u00a0\u00bboff\u00a0\u00bb make_equal=\u00a0\u00bboff\u00a0\u00bb column_padding_mobile=\u00a0\u00bbon\u00a0\u00bb][et_pb_column type=\u00a0\u00bb1_2&Prime;][et_pb_image admin_label=\u00a0\u00bbImage\u00a0\u00bb src=\u00a0\u00bbhttp:\/\/ecolesayu.deuxspirales.fr\/wp-content\/uploads\/2020\/06\/meca3.png\u00a0\u00bb alt=\u00a0\u00bbFigure 3 : Forces appliqu\u00e9s au corps au d\u00e9marrage.\u00a0\u00bb title_text=\u00a0\u00bbFigure 3 : Forces appliqu\u00e9s au corps au d\u00e9marrage.\u00a0\u00bb show_in_lightbox=\u00a0\u00bboff\u00a0\u00bb url_new_window=\u00a0\u00bboff\u00a0\u00bb animation=\u00a0\u00bboff\u00a0\u00bb sticky=\u00a0\u00bboff\u00a0\u00bb align=\u00a0\u00bbcenter\u00a0\u00bb force_fullwidth=\u00a0\u00bboff\u00a0\u00bb always_center_on_mobile=\u00a0\u00bbon\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb] [\/et_pb_image][et_pb_text admin_label=\u00a0\u00bbTexte\u00a0\u00bb background_layout=\u00a0\u00bblight\u00a0\u00bb text_orientation=\u00a0\u00bbleft\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb]<\/p>\n<p style=\"text-align: center;\">Figure 3 : Forces appliqu\u00e9s au corps au d\u00e9marrage.<\/p>\n<p>[\/et_pb_text][\/et_pb_column][et_pb_column type=\u00a0\u00bb1_2&Prime;][et_pb_image admin_label=\u00a0\u00bbImage\u00a0\u00bb src=\u00a0\u00bbhttp:\/\/ecolesayu.deuxspirales.fr\/wp-content\/uploads\/2020\/06\/meca4.png\u00a0\u00bb alt=\u00a0\u00bbFigure 4 : Muscles du d\u00e9marrage.\u00a0\u00bb title_text=\u00a0\u00bbFigure 4 : Muscles du d\u00e9marrage.\u00a0\u00bb show_in_lightbox=\u00a0\u00bboff\u00a0\u00bb url_new_window=\u00a0\u00bboff\u00a0\u00bb animation=\u00a0\u00bboff\u00a0\u00bb sticky=\u00a0\u00bboff\u00a0\u00bb align=\u00a0\u00bbcenter\u00a0\u00bb force_fullwidth=\u00a0\u00bboff\u00a0\u00bb always_center_on_mobile=\u00a0\u00bbon\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb] [\/et_pb_image][et_pb_text admin_label=\u00a0\u00bbTexte\u00a0\u00bb background_layout=\u00a0\u00bblight\u00a0\u00bb text_orientation=\u00a0\u00bbleft\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb]<\/p>\n<p style=\"text-align: center;\">Figure 4 : Muscles du d\u00e9marrage.<\/p>\n<p>[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row admin_label=\u00a0\u00bbLigne\u00a0\u00bb make_fullwidth=\u00a0\u00bboff\u00a0\u00bb use_custom_width=\u00a0\u00bboff\u00a0\u00bb width_unit=\u00a0\u00bbon\u00a0\u00bb use_custom_gutter=\u00a0\u00bboff\u00a0\u00bb custom_padding=\u00a0\u00bb10px|10px\u00a0\u00bb padding_mobile=\u00a0\u00bboff\u00a0\u00bb allow_player_pause=\u00a0\u00bboff\u00a0\u00bb parallax=\u00a0\u00bboff\u00a0\u00bb parallax_method=\u00a0\u00bboff\u00a0\u00bb make_equal=\u00a0\u00bboff\u00a0\u00bb column_padding_mobile=\u00a0\u00bbon\u00a0\u00bb][et_pb_column type=\u00a0\u00bb1_2&Prime;][et_pb_text admin_label=\u00a0\u00bbTexte\u00a0\u00bb background_layout=\u00a0\u00bblight\u00a0\u00bb text_orientation=\u00a0\u00bbleft\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb]<\/p>\n<p>D&rsquo;apr\u00e8s les lois de Newton, apr\u00e8s projection sur l&rsquo;horizontale<\/p>\n<p><a href=\"http:\/\/ecolesayu.deuxspirales.fr\/wp-content\/uploads\/2020\/06\/meca5.png\"><img loading=\"lazy\" class=\"alignnone size-full wp-image-2057\" src=\"http:\/\/ecolesayu.deuxspirales.fr\/wp-content\/uploads\/2020\/06\/meca5.png\" alt=\"meca5\" width=\"112\" height=\"48\" \/><\/a><br \/>\nou Ph et Rh sont les composantes horizontales du poids et de la r\u00e9action. P \u00e9tant strictement vertical, Ph est nul. Rh est \u00e9gal \u00e0 P divis\u00e9 par tan(\u03b1) (fig5)<br \/>\nSoit<\/p>\n<p><a href=\"http:\/\/ecolesayu.deuxspirales.fr\/wp-content\/uploads\/2020\/06\/meca6.png\"><img loading=\"lazy\" class=\"alignnone size-full wp-image-2058\" src=\"http:\/\/ecolesayu.deuxspirales.fr\/wp-content\/uploads\/2020\/06\/meca6.png\" alt=\"meca6\" width=\"117\" height=\"47\" \/><\/a><\/p>\n<p>Sachant que plus \u03b1 est proche de 0 plus tan(\u03b1) est grand on peut en conclure que plus \u03b1 est proche de 0 (plus R s&rsquo;approche de l\u2019horizontale), plus l&rsquo;acc\u00e9l\u00e9ration sera grande.<\/p>\n<p>[\/et_pb_text][\/et_pb_column][et_pb_column type=\u00a0\u00bb1_2&Prime;][et_pb_image admin_label=\u00a0\u00bbImage\u00a0\u00bb src=\u00a0\u00bbhttp:\/\/ecolesayu.deuxspirales.fr\/wp-content\/uploads\/2020\/06\/meca7.png\u00a0\u00bb alt=\u00a0\u00bbFigure 5 : calcul de la composante horizontale.\u00a0\u00bb title_text=\u00a0\u00bbFigure 5 : calcul de la composante horizontale.\u00a0\u00bb show_in_lightbox=\u00a0\u00bboff\u00a0\u00bb url_new_window=\u00a0\u00bboff\u00a0\u00bb animation=\u00a0\u00bboff\u00a0\u00bb sticky=\u00a0\u00bboff\u00a0\u00bb align=\u00a0\u00bbcenter\u00a0\u00bb force_fullwidth=\u00a0\u00bboff\u00a0\u00bb always_center_on_mobile=\u00a0\u00bbon\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb] [\/et_pb_image][et_pb_text admin_label=\u00a0\u00bbTexte\u00a0\u00bb background_layout=\u00a0\u00bblight\u00a0\u00bb text_orientation=\u00a0\u00bbleft\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb]<\/p>\n<p style=\"text-align: center;\">Figure 5 : calcul de la composante horizontale.<\/p>\n<p>[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row admin_label=\u00a0\u00bbLigne\u00a0\u00bb make_fullwidth=\u00a0\u00bboff\u00a0\u00bb use_custom_width=\u00a0\u00bboff\u00a0\u00bb width_unit=\u00a0\u00bbon\u00a0\u00bb use_custom_gutter=\u00a0\u00bboff\u00a0\u00bb custom_padding=\u00a0\u00bb10px|10px\u00a0\u00bb padding_mobile=\u00a0\u00bboff\u00a0\u00bb allow_player_pause=\u00a0\u00bboff\u00a0\u00bb parallax=\u00a0\u00bboff\u00a0\u00bb parallax_method=\u00a0\u00bboff\u00a0\u00bb make_equal=\u00a0\u00bboff\u00a0\u00bb column_padding_mobile=\u00a0\u00bbon\u00a0\u00bb][et_pb_column type=\u00a0\u00bb4_4&Prime;][et_pb_text admin_label=\u00a0\u00bbTexte\u00a0\u00bb background_layout=\u00a0\u00bblight\u00a0\u00bb text_orientation=\u00a0\u00bbleft\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb]<\/p>\n<p><strong>AMELIORER L&rsquo;ACC\u00c9L\u00c9RATION INITIALE<\/strong><\/p>\n<p>[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row admin_label=\u00a0\u00bbLigne\u00a0\u00bb make_fullwidth=\u00a0\u00bboff\u00a0\u00bb use_custom_width=\u00a0\u00bboff\u00a0\u00bb width_unit=\u00a0\u00bbon\u00a0\u00bb use_custom_gutter=\u00a0\u00bboff\u00a0\u00bb custom_padding=\u00a0\u00bb10px|10px\u00a0\u00bb padding_mobile=\u00a0\u00bboff\u00a0\u00bb allow_player_pause=\u00a0\u00bboff\u00a0\u00bb parallax=\u00a0\u00bboff\u00a0\u00bb parallax_method=\u00a0\u00bboff\u00a0\u00bb make_equal=\u00a0\u00bboff\u00a0\u00bb column_padding_mobile=\u00a0\u00bbon\u00a0\u00bb][et_pb_column type=\u00a0\u00bb1_2&Prime;][et_pb_text admin_label=\u00a0\u00bbTexte\u00a0\u00bb background_layout=\u00a0\u00bblight\u00a0\u00bb text_orientation=\u00a0\u00bbleft\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb]<\/p>\n<p>Comme on la vu au dessus, pour augmenter l&rsquo;acc\u00e9l\u00e9ration il faut r\u00e9duire l&rsquo;angle \u03b1. On peut agir sur deux points.<\/p>\n<ul>\n<li>Agir sur le point G : il va pouvoir \u00eatre abaiss\u00e9 en fl\u00e9chissant les genou et l&rsquo;avancer \u00e0 l&rsquo;aplomb des orteils.<\/li>\n<li>Agir sur le point d&rsquo;appui au sol : on a vu que pour cr\u00e9er l&rsquo;acc\u00e9l\u00e9ration on a d\u00e9j\u00e0 post\u00e9rioris\u00e9 le point d&rsquo;appui. On peut augmenter cela en reculant un pied.<\/li>\n<\/ul>\n<p>Les limites de ces adaptations vont \u00eatre notamment la limite de flexion dorsale de cheville et l\u2019adh\u00e9rence du pied au au sol.<br \/>\nIl est \u00e0 noter qu&rsquo;en avan\u00e7ant le centre de gravit\u00e9 on augmente la capacit\u00e9 d&rsquo;acc\u00e9l\u00e9ration vers l&rsquo;avant mais on r\u00e9duit celle vers l&rsquo;arri\u00e8re.<\/p>\n<p>[\/et_pb_text][\/et_pb_column][et_pb_column type=\u00a0\u00bb1_2&Prime;][et_pb_image admin_label=\u00a0\u00bbImage\u00a0\u00bb src=\u00a0\u00bbhttp:\/\/ecolesayu.deuxspirales.fr\/wp-content\/uploads\/2020\/06\/meca8.png\u00a0\u00bb alt=\u00a0\u00bbFigure 6 : Am\u00e9lioration de l&rsquo;acc\u00e9l\u00e9ration initiale.\u00a0\u00bb title_text=\u00a0\u00bbFigure 6 : Am\u00e9lioration de l&rsquo;acc\u00e9l\u00e9ration initiale.\u00a0\u00bb show_in_lightbox=\u00a0\u00bboff\u00a0\u00bb url_new_window=\u00a0\u00bboff\u00a0\u00bb animation=\u00a0\u00bboff\u00a0\u00bb sticky=\u00a0\u00bboff\u00a0\u00bb align=\u00a0\u00bbcenter\u00a0\u00bb force_fullwidth=\u00a0\u00bboff\u00a0\u00bb always_center_on_mobile=\u00a0\u00bbon\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb] [\/et_pb_image][et_pb_text admin_label=\u00a0\u00bbTexte\u00a0\u00bb background_layout=\u00a0\u00bblight\u00a0\u00bb text_orientation=\u00a0\u00bbleft\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb]<\/p>\n<p style=\"text-align: center;\">Figure 6 : Am\u00e9lioration de l&rsquo;acc\u00e9l\u00e9ration initiale.<\/p>\n<p>[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row admin_label=\u00a0\u00bbLigne\u00a0\u00bb make_fullwidth=\u00a0\u00bboff\u00a0\u00bb use_custom_width=\u00a0\u00bboff\u00a0\u00bb width_unit=\u00a0\u00bbon\u00a0\u00bb use_custom_gutter=\u00a0\u00bboff\u00a0\u00bb custom_padding=\u00a0\u00bb10px|10px\u00a0\u00bb padding_mobile=\u00a0\u00bboff\u00a0\u00bb allow_player_pause=\u00a0\u00bboff\u00a0\u00bb parallax=\u00a0\u00bboff\u00a0\u00bb parallax_method=\u00a0\u00bboff\u00a0\u00bb make_equal=\u00a0\u00bboff\u00a0\u00bb column_padding_mobile=\u00a0\u00bbon\u00a0\u00bb][et_pb_column type=\u00a0\u00bb4_4&Prime;][et_pb_text admin_label=\u00a0\u00bbTexte\u00a0\u00bb background_layout=\u00a0\u00bblight\u00a0\u00bb text_orientation=\u00a0\u00bbleft\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb]<\/p>\n<p><strong>EFFICACITE DU DEPLACEMENT DANS LE CADRE MARTIAL<\/strong><\/p>\n<p>Dans le cadre martial, on va vouloir maximiser l&rsquo;acc\u00e9l\u00e9ration et on va chercher \u00e0 cacher le mouvement. Tout mouvement dans le plan frontal par rapport \u00e0 l&rsquo;opposant lui sera facilement perceptible. Dans son axe ant\u00e9ropost\u00e9rieur, la perception sera plus tardive. Cela implique que le centre de gravit\u00e9 doit avoir un d\u00e9placement strictement horizontal.<\/p>\n<p>Si on reprend le cas de la figure 3, en avan\u00e7ant le centre de gravit\u00e9 (G) va perdre de la hauteur. Il est en rotation autour de la cheville et les membres sup\u00e9rieurs \u00e9tant tendu ils ne peuvent pas compenser avant que G ne passe \u00e0 la verticale d&rsquo;une ligne passant par les articulations m\u00e9tatarso-phalangienne. Pour \u00e9viter cela il faut d\u00e9marrer avec les genoux fl\u00e9chis. En se tendant les genoux vont pouvoir compenser la perte de hauteur durant l&rsquo;avanc\u00e9e du centre de gravit\u00e9.<\/p>\n<p><strong>DESEQUILIBRE <\/strong><\/p>\n<p>On va d\u00e9finir le d\u00e9s\u00e9quilibre comme l&rsquo;incapacit\u00e9 \u00e0 conserver la hauteur de G. cela appara\u00eet quand la composante verticale de R ne compense plus P. Notre corps est normalement en capacit\u00e9 de faire g\u00e9n\u00e9rer au sol une R\u00e9sistance au moins \u00e9gale au poids. Donc on est sur de rester en \u00e9quilibre tant que G reste \u00e0 l&rsquo;aplomb du point d&rsquo;appui, c&rsquo;est \u00e0 dire tant que G se projette au sol dans le polygone de sustentation (surface dessin\u00e9e par les pieds et l&rsquo;espace entre eux dans ce cas).<\/p>\n<p><a href=\"http:\/\/ecolesayu.deuxspirales.fr\/wp-content\/uploads\/2020\/06\/mecatab.png\"><img loading=\"lazy\" class=\"alignnone size-full wp-image-2062 alignright\" src=\"http:\/\/ecolesayu.deuxspirales.fr\/wp-content\/uploads\/2020\/06\/mecatab.png\" alt=\"mecatab\" width=\"467\" height=\"193\" srcset=\"https:\/\/ecolesayu.deuxspirales.fr\/wp-content\/uploads\/2020\/06\/mecatab.png 467w, https:\/\/ecolesayu.deuxspirales.fr\/wp-content\/uploads\/2020\/06\/mecatab-300x124.png 300w\" sizes=\"(max-width: 467px) 100vw, 467px\" \/><\/a>Si la projection de G ce fait en dehors du polygone de sustentation, R est forcement oblique. Cela g\u00e9n\u00e8re une acc\u00e9l\u00e9ration de G et donc son d\u00e9placement, augmentant d&rsquo;autant plus l&rsquo;obliquit\u00e9 de R, ainsi que l&rsquo;acc\u00e9l\u00e9ration de G.<\/p>\n<p>Plus R est oblique plus il faut qu&rsquo;il augmente pour avoir une composante verticale compensant le poids P (tab. 1).<\/p>\n<p>[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row admin_label=\u00a0\u00bbLigne\u00a0\u00bb make_fullwidth=\u00a0\u00bboff\u00a0\u00bb use_custom_width=\u00a0\u00bboff\u00a0\u00bb width_unit=\u00a0\u00bbon\u00a0\u00bb use_custom_gutter=\u00a0\u00bboff\u00a0\u00bb custom_padding=\u00a0\u00bb10px|10px\u00a0\u00bb padding_mobile=\u00a0\u00bboff\u00a0\u00bb allow_player_pause=\u00a0\u00bboff\u00a0\u00bb parallax=\u00a0\u00bboff\u00a0\u00bb parallax_method=\u00a0\u00bboff\u00a0\u00bb make_equal=\u00a0\u00bboff\u00a0\u00bb column_padding_mobile=\u00a0\u00bbon\u00a0\u00bb][et_pb_column type=\u00a0\u00bb1_2&Prime;][et_pb_text admin_label=\u00a0\u00bbTexte\u00a0\u00bb background_layout=\u00a0\u00bblight\u00a0\u00bb text_orientation=\u00a0\u00bbleft\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb]<\/p>\n<p>Il arrivera donc un moment ou le corps ne sera plus en capacit\u00e9 de faire g\u00e9n\u00e9rer assez de r\u00e9sistance R au sol pour compenser P. Il faudra alors modifier notre polygone de sustentation pour modifier le point d\u2019application de R et ainsi le redresser. Il faut avancer un pied.<br \/>\nEn avan\u00e7ant le pied nous allons commencer par r\u00e9duire notre polygone de sustentation. Celui-ci ce r\u00e9duit \u00e0 la surface occup\u00e9e par notre seul pied d&rsquo;appui. Hors sans pr\u00e9paration G ce projetant entre les deux pieds en appui bipodal, il se projette hors du nouveau polygone en appui unipodal. Ce qui g\u00e9n\u00e8re une acc\u00e9l\u00e9ration vers le c\u00f4t\u00e9, ce qui va d\u00e9placer le corps sur le c\u00f4t\u00e9(fig.7).<\/p>\n<p>Pour g\u00e9rer cela nous avons deux solutions :<\/p>\n<ul>\n<li>Anticiper en d\u00e9pla\u00e7ant G \u00e0 l&rsquo;aplomb du pied d&rsquo;appui avant de d\u00e9placer l&rsquo;autre pied.<\/li>\n<li>Compenser au retour de l&rsquo;appui du pied qui c&rsquo;est avanc\u00e9 en g\u00e9n\u00e9rant une acc\u00e9l\u00e9ration \u00e9quivalente.<\/li>\n<\/ul>\n<p>[\/et_pb_text][\/et_pb_column][et_pb_column type=\u00a0\u00bb1_2&Prime;][et_pb_image admin_label=\u00a0\u00bbImage\u00a0\u00bb src=\u00a0\u00bbhttp:\/\/ecolesayu.deuxspirales.fr\/wp-content\/uploads\/2020\/06\/meca9.png\u00a0\u00bb alt=\u00a0\u00bbFigure 7 : acc\u00e9l\u00e9ration transversale\u00a0\u00bb title_text=\u00a0\u00bbFigure 7 : acc\u00e9l\u00e9ration transversale\u00a0\u00bb show_in_lightbox=\u00a0\u00bboff\u00a0\u00bb url_new_window=\u00a0\u00bboff\u00a0\u00bb animation=\u00a0\u00bboff\u00a0\u00bb sticky=\u00a0\u00bboff\u00a0\u00bb align=\u00a0\u00bbcenter\u00a0\u00bb force_fullwidth=\u00a0\u00bboff\u00a0\u00bb always_center_on_mobile=\u00a0\u00bbon\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb] [\/et_pb_image][et_pb_text admin_label=\u00a0\u00bbTexte\u00a0\u00bb background_layout=\u00a0\u00bblight\u00a0\u00bb text_orientation=\u00a0\u00bbleft\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb]<\/p>\n<p style=\"text-align: center;\">Figure 7 : acc\u00e9l\u00e9ration transversale<\/p>\n<p>[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row admin_label=\u00a0\u00bbLigne\u00a0\u00bb make_fullwidth=\u00a0\u00bboff\u00a0\u00bb use_custom_width=\u00a0\u00bboff\u00a0\u00bb width_unit=\u00a0\u00bbon\u00a0\u00bb use_custom_gutter=\u00a0\u00bboff\u00a0\u00bb custom_padding=\u00a0\u00bb10px|\u00a0\u00bb padding_mobile=\u00a0\u00bboff\u00a0\u00bb allow_player_pause=\u00a0\u00bboff\u00a0\u00bb parallax=\u00a0\u00bboff\u00a0\u00bb parallax_method=\u00a0\u00bboff\u00a0\u00bb make_equal=\u00a0\u00bboff\u00a0\u00bb column_padding_mobile=\u00a0\u00bbon\u00a0\u00bb][et_pb_column type=\u00a0\u00bb1_2&Prime;][et_pb_image admin_label=\u00a0\u00bbImage\u00a0\u00bb src=\u00a0\u00bbhttp:\/\/ecolesayu.deuxspirales.fr\/wp-content\/uploads\/2020\/06\/meca10.png\u00a0\u00bb show_in_lightbox=\u00a0\u00bboff\u00a0\u00bb url_new_window=\u00a0\u00bboff\u00a0\u00bb animation=\u00a0\u00bboff\u00a0\u00bb sticky=\u00a0\u00bboff\u00a0\u00bb align=\u00a0\u00bbcenter\u00a0\u00bb force_fullwidth=\u00a0\u00bboff\u00a0\u00bb always_center_on_mobile=\u00a0\u00bbon\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb] [\/et_pb_image][et_pb_text admin_label=\u00a0\u00bbTexte\u00a0\u00bb background_layout=\u00a0\u00bblight\u00a0\u00bb text_orientation=\u00a0\u00bbleft\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb]<\/p>\n<p style=\"text-align: center;\">Sans anticipation<\/p>\n<p>[\/et_pb_text][\/et_pb_column][et_pb_column type=\u00a0\u00bb1_2&Prime;][et_pb_image admin_label=\u00a0\u00bbImage\u00a0\u00bb src=\u00a0\u00bbhttp:\/\/ecolesayu.deuxspirales.fr\/wp-content\/uploads\/2020\/06\/meca11.png\u00a0\u00bb show_in_lightbox=\u00a0\u00bboff\u00a0\u00bb url_new_window=\u00a0\u00bboff\u00a0\u00bb animation=\u00a0\u00bboff\u00a0\u00bb sticky=\u00a0\u00bboff\u00a0\u00bb align=\u00a0\u00bbcenter\u00a0\u00bb force_fullwidth=\u00a0\u00bboff\u00a0\u00bb always_center_on_mobile=\u00a0\u00bbon\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb] [\/et_pb_image][et_pb_text admin_label=\u00a0\u00bbTexte\u00a0\u00bb background_layout=\u00a0\u00bblight\u00a0\u00bb text_orientation=\u00a0\u00bbleft\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb]<\/p>\n<p style=\"text-align: center;\">Avec anticipation<\/p>\n<p>[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row admin_label=\u00a0\u00bbLigne\u00a0\u00bb][et_pb_column type=\u00a0\u00bb4_4&Prime;][et_pb_text admin_label=\u00a0\u00bbTexte\u00a0\u00bb background_layout=\u00a0\u00bblight\u00a0\u00bb text_orientation=\u00a0\u00bbleft\u00a0\u00bb use_border_color=\u00a0\u00bboff\u00a0\u00bb border_color=\u00a0\u00bb#ffffff\u00a0\u00bb border_style=\u00a0\u00bbsolid\u00a0\u00bb]<\/p>\n<p style=\"text-align: center;\">Figure 8 : D\u00e9placement de G du d\u00e9marrage \u00e0 la phase d&rsquo;appui unipodal.<\/p>\n<p>En fonction de la strat\u00e9gie utilis\u00e9e, soit le corps se d\u00e9place vers le pied d&rsquo;appui au d\u00e9but du mouvement, soit le corps se d\u00e9place vers le pied mobile au cours du mouvement (fig.8). En se repla\u00e7ant dans un contexte martial, on voit que la strat\u00e9gie de d\u00e9placer le centre de gravit\u00e9 au dessus du point d&rsquo;appui va donner tr\u00e8s t\u00f4t l&rsquo;information du mouvement \u00e0 l&rsquo;adversaire. Elle ne semble pertinente que si elle est appliqu\u00e9e pr\u00e9cocement avant que l&rsquo;intention du mouvement n&rsquo;arrive.\u00a0 L&rsquo;autre strat\u00e9gie va permettre d&rsquo;\u00eatre per\u00e7u plus tardivement, et permet de choisir le pied d&rsquo;appui qu&rsquo;au dernier moment.<\/p>\n<p><em>Olivier<\/em><\/p>\n<p>[\/et_pb_text][\/et_pb_column][\/et_pb_row][\/et_pb_section]<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Dossier \u00ab\u00a0scientifique\u00a0\u00bb \u00e9crit par Olivier<\/p>\n","protected":false},"author":1,"featured_media":2069,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"aside","meta":{"_et_pb_use_builder":"on","_et_pb_old_content":"<p>Nous allons poser les bases m\u00e9caniques du d\u00e9placement du corps dans l'espace.<br \/>En l'absence de mouvement deux forces s\u2019appliquent au corps(fig.1) :<\/p>","_et_gb_content_width":""},"categories":[1],"tags":[],"_links":{"self":[{"href":"https:\/\/ecolesayu.deuxspirales.fr\/index.php\/wp-json\/wp\/v2\/posts\/2050"}],"collection":[{"href":"https:\/\/ecolesayu.deuxspirales.fr\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ecolesayu.deuxspirales.fr\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ecolesayu.deuxspirales.fr\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ecolesayu.deuxspirales.fr\/index.php\/wp-json\/wp\/v2\/comments?post=2050"}],"version-history":[{"count":7,"href":"https:\/\/ecolesayu.deuxspirales.fr\/index.php\/wp-json\/wp\/v2\/posts\/2050\/revisions"}],"predecessor-version":[{"id":2091,"href":"https:\/\/ecolesayu.deuxspirales.fr\/index.php\/wp-json\/wp\/v2\/posts\/2050\/revisions\/2091"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/ecolesayu.deuxspirales.fr\/index.php\/wp-json\/wp\/v2\/media\/2069"}],"wp:attachment":[{"href":"https:\/\/ecolesayu.deuxspirales.fr\/index.php\/wp-json\/wp\/v2\/media?parent=2050"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ecolesayu.deuxspirales.fr\/index.php\/wp-json\/wp\/v2\/categories?post=2050"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ecolesayu.deuxspirales.fr\/index.php\/wp-json\/wp\/v2\/tags?post=2050"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}