A motion assistance apparatus (1, 2, 3, 4, 5, 6, 7) comprising: a proximal support (11, 21, 31, 41, 51, 61, 71) configured to support a waist or pelvis of a user; a distal support (12, 22, 32, 42, 52, 62, 72) configured to support a foot of the user, the distal support comprising a first portion (121, 221, 321, 421, 521, 621, 721) and a second portion (122, 222, 322, 422, 522, 622, 722); a support assembly (13, 23, 33, 43, 53, 63, 73) configured to connect the proximal support and the distal support, and configured to adjust a rotation angle of the distal support; the support assembly (13, 23, 33, 43, 53, 63, 73) comprising: a first spring configured to connect the proximal support and the first portion of the distal support; and a second spring configured to connect the proximal support and the second portion of the distal support, wherein the first spring is a first virtual spring virtually connecting the proximal support (41, 51, 61, 71) to the first portion (421, 521, 621, 721) of the distal support (42, 52, 62, 72); the seond spring is a second virtual spring virtually connecting the proximal support (41, 51, 61, 71) to the second portion (422, 522, 622, 722) of the distal support (42, 52, 62, 72); it further comprises a controller configured to control the support assembly based on a virtual dual spring-mass model designed using the proximal support as a body of mass, the virtual dual spring-mass model comprising the first virtual spring and the second virtual spring; in the virtual model, only the first virtual spring and the second virtual spring of said support assembly (13, 23, 33, 43, 53, 63, 73) define a separation distance between the proximal support and the distal support; and wherein at least two joints (J1, J2, J3) are arranged between the waist or pelvis and the foot of the user. a proximal support (11, 21, 31, 41, 51, 61, 71) configured to support a waist or pelvis of a user; a distal support (12, 22, 32, 42, 52, 62, 72) configured to support a foot of the user, the distal support comprising a first portion (121, 221, 321, 421, 521, 621, 721) and a second portion (122, 222, 322, 422, 522, 622, 722); a support assembly (13, 23, 33, 43, 53, 63, 73) configured to connect the proximal support and the distal support, and configured to adjust a rotation angle of the distal support; the support assembly (13, 23, 33, 43, 53, 63, 73) comprising: a first spring configured to connect the proximal support and the first portion of the distal support; and a second spring configured to connect the proximal support and the second portion of the distal support, wherein a first spring configured to connect the proximal support and the first portion of the distal support; and a second spring configured to connect the proximal support and the second portion of the distal support, wherein the first spring is a first virtual spring virtually connecting the proximal support (41, 51, 61, 71) to the first portion (421, 521, 621, 721) of the distal support (42, 52, 62, 72); the seond spring is a second virtual spring virtually connecting the proximal support (41, 51, 61, 71) to the second portion (422, 522, 622, 722) of the distal support (42, 52, 62, 72); it further comprises a controller configured to control the support assembly based on a virtual dual spring-mass model designed using the proximal support as a body of mass, the virtual dual spring-mass model comprising the first virtual spring and the second virtual spring; in the virtual model, only the first virtual spring and the second virtual spring of said support assembly (13, 23, 33, 43, 53, 63, 73) define a separation distance between the proximal support and the distal support; and wherein at least two joints (J1, J2, J3) are arranged between the waist or pelvis and the foot of the user.