places weight downward on crutch 90 the downward force of the user on crutch 90 results in an opposite force upward from floor 80 and through the foot 26 and onto shaft 22 shaft 22 transfers the force at upper end 28 to spring 30 spring 30 in turn compresses in response to this force and the exposed length of shaft 22 decreases to a length 34 y 34 the compression of spring 30 absorbs a portion of the shock the underarm of the user receives when a load is placed on crutch 90 by a user the spring constant k of spring 30 is appropriate for the size and capability of a particular user each subsequent user should accordingly select a fixture 10 with a lower leg tube 11 having a spring with a desired spring constant k referring now to fig5 as the user enters the final portion of the step the user transfers weight to his left leg not shown thereby decreasing the force placed onto crutch 90 spring 30 expands in response to the decrease in force on crutch 90 increasing the exposed length of shaft 22 to a value of 34 z 34 and giving.