The ornamental design for a weightliftingbelt, as shown and described.
FIG. 1 is a front elevation view of a weightlifting belt showing our new design; and,
FIG. 2 is a perspective view thereof in the closed position.
The broken lines of FIGS. 1-2 illustrate portions of a weightlifting belt that form no part of the claimed design. The rear side of the weightlifting belt forms no part of the claimed design and is therefore not shown.