A method for measuring the variation of the inductance in micro Henry (μHenry) of a magnetic coil created by an inductive elongation sensor yarn (10, 21, 44, 64, 74, 78, 89, 120), comprising the following steps: - (i) providing a device (1,20) comprising at least one elastic textile part (5, 24, 26, 30, 32, 36, 38, 85) in at least one first direction, the textile part (5, 24, 26, 30, 32, 36, 38, 85) comprising at least one inductive elongation sensor yarn (10, 21, 44, 64, 74, 78, 89, 120), said inductive elongation sensor yarn (10, 21, 44, 64, 74, 78, 89, 120) comprising an elastic core yarn and an electrically conductive cover yarn forming turns around said elastic core yarn, and the electrically conductive cover yarn comprises a filament or a plurality of filaments, each of the or said filaments comprising an electrically conductive core covered with an electrically non-conductive sheath; - (ii) measuring the initial inductance value I0 in micro Henry (μHenry) of the elastic textile part (5, 24, 26, 30, 32, 36, 38, 85) at rest in the first direction between two points A and B in-between which the at least one inductive elongation sensor yarn (10, 21, 44, 64, 74, 78, 89, 120) extends; - (iii) measuring the inductance value I1 in micro Henry (μHenry) of the elastic textile part (10, 21, 44, 64, 74, 78, 89, 120) in a first state stretched between the two points A and B, more particularly at an elongation of 20 mm, in the first direction; - (iv) optionally measuring the value of inductance In of the elastic textile part (10, 21, 44, 64, 74, 78, 89, 120) in an nth state stretched between the two points A and B, particularly under an elongation of 20 mm, in the first direction, n being a positive integer other than zero, the nth stretched state being different from the nth-1 stretched state; - (v) recovering the variation of the inductance in micro Henry (μHenry) by the difference between I0 (μHenry) and I1 (μHenry), which is preferably different from zero. - (i) providing a device (1,20) comprising at least one elastic textile part (5, 24, 26, 30, 32, 36, 38, 85) in at least one first direction, the textile part (5, 24, 26, 30, 32, 36, 38, 85) comprising at least one inductive elongation sensor yarn (10, 21, 44, 64, 74, 78, 89, 120), said inductive elongation sensor yarn (10, 21, 44, 64, 74, 78, 89, 120) comprising an elastic core yarn and an electrically conductive cover yarn forming turns around said elastic core yarn, and the electrically conductive cover yarn comprises a filament or a plurality of filaments, each of the or said filaments comprising an electrically conductive core covered with an electrically non-conductive sheath; - (ii) measuring the initial inductance value I0 in micro Henry (μHenry) of the elastic textile part (5, 24, 26, 30, 32, 36, 38, 85) at rest in the first direction between two points A and B in-between which the at least one inductive elongation sensor yarn (10, 21, 44, 64, 74, 78, 89, 120) extends; - (iii) measuring the inductance value I1 in micro Henry (μHenry) of the elastic textile part (10, 21, 44, 64, 74, 78, 89, 120) in a first state stretched between the two points A and B, more particularly at an elongation of 20 mm, in the first direction; - (iv) optionally measuring the value of inductance In of the elastic textile part (10, 21, 44, 64, 74, 78, 89, 120) in an nth state stretched between the two points A and B, particularly under an elongation of 20 mm, in the first direction, n being a positive integer other than zero, the nth stretched state being different from the nth-1 stretched state; - (v) recovering the variation of the inductance in micro Henry (μHenry) by the difference between I0 (μHenry) and I1 (μHenry), which is preferably different from zero.