urging it to a minimum spacing position relative to the fixed restraining bar 4a as is readily apparent from the drawings the top portions of both the restraining bars 4a and 4b extend above the top surface 2e of the base element 2 the inner walls of the top portions of restraining bars 4a and 4b are respectively provided with opposed parallel grooves 4f and 4g respectively such grooves thus define a longitudinally extending track it will be noted that the inner top corners of restraining bars 4a and 4b are respectively provided with convex rounded surfaces 4h and 4j for a purpose to hereinafter described the aforedescribed elements of the restraining apparatus 1 are all fixedly mounted in the micro gravity compartment the cooperating apparatus comprises a cleat assemblage 10 which is secured to the bottom of one or both shoes of the person to be restrained the cleat assemblage 10 as shown in fig4 comprises a metallic plate 12 which is embedded in or otherwise suitably secured to the bottom of each shoe s a flanged cleat unit 14 is then secured to such plate by a plurality of bolts 13 the flanged cleat 14 is of circular configuration and defines a peripheral flange 14a which has convex upper and bottom peripheral edges the diameter of the flange 14a is selected to be substantially equal to the minimum spacing.