The assembly (24) comprises: a first structure (10) extending in a first overall direction (G1), a second structure (12), and a bearing structure (30) comprising filamentary bearing elements (32) comprising at least one filamentary bearing portion (74) extending between the first structure (10) and the second structure (12), the first structure (10) being arranged such that, for a length at rest L of the first structure (10) in the first overall direction (G1), the elongation at maximum force Art of the first structure in the first overall direction (G1) satisfies: Art≤(2π×H)/L, in which H0×K≤H where H0 is the mean straight-line distance between an internal face (42) of the first structure (10) and an internal face (46) of the second structure (12) when each filamentary bearing portion (74) is at rest, and K=0.50.