A prosthesis with a lower limb attachment part, a foot part, a connection element with a joint function that connects the lower limb attachment part with the foot part, and a release device which can be brought into a locking position in which the foot part and the lower limb attachment part are connected to each other in a rotationally fixed manner at least relative to a dorsal extension movement, and into a release position in which the foot part can be rotated relative to the lower limb attachment part. The release device is designed to passively switch from the locking position into the release position when a variable which correlates to an ankle torque (M) in the connection element lies above a pre-set threshold.
