A boot including an outer sole assembly, the outer sole assembly extending lengthwise from a rear end to a front end, widthwise between a lateral side and a medial side, and heightwise between a free surface and a connection surface, the outer sole assembly having a longitudinal groove that opens out in the area of the free surface. The longitudinal groove opens out in the area of the free surface, the groove having a length ranging between 30 and 100% of the length of the outer sole assembly, a width ranging between 25 and 45 mm, and a depth greater than or equal to 4 mm, the groove being compatible with one or more guiding ribs.