A conditional braking knee includes an upper member configured to couple to a prosthetic socket. A braking member couples to the upper member. A lower member couples to the braking member and is configured to rotate with respect to the upper member. A flexion coupler couples to the braking member and is configured to couple to a prosthetic foot. The braking member is configured to prevent a rotation of the upper member relative to the lower member in response to a flexion of the prosthetic foot communicated to the braking member through the flexion coupler. In implementations the braking member is a clamping member rotatably coupled to the upper member with a first axle, the lower member is rotatably coupled to the clamping member with a second axle, and the clamping member prevents a rotation of the upper member relative to the lower member by clamping on the first axle.
