an alpine ski boot , the rod of which has a front collar and a rear cap arranged about a common axis , and the foot accommodating shell of which houses , in its interior , a tarsal support casing . the collar and the cap , on the one hand , and the casing , on the other hand , are respectively kept in position pressing against a skier &# 39 ; s leg and against the kick portion of his foot , with a flexible brace cooperating with an element exerting traction by winding , allowing a phase of rapid approach , then a phase for the adjustment of the pressure applied to the skier &# 39 ; s foot and leg .