Some embodiments relate to a device for reducing venous blood flow in a human limb. The device of some embodiments comprises: a first rigid part having a first non-linear inner profile； a second rigid part having a second inner profile generally facing the first inner profile； and a coupling portion that couples the first and second parts together while allowing relative movement of the first and second parts between a clamped position and an unclamped position. The first and second inner profiles are arranged to press against veins in the limb when the device is in the clamped position and thereby reduce venous blood flow in the limb.
