Ladder and a ladder rung

A ladder comprising:

• a first rail;
• a second rail;
• a rung disposed between the first rail and the second rail, the rung including:
• a tread portion having a first edge and a second edge that extend between the first rail and the second rail along a length of the rung;
• a first planar wall extending from the tread portion, the first planar wall disposed adjacent to the first edge;
• a second planar wall extending from the tread portion, the second planar wall disposed adjacent to the second edge;
• a third planar wall extending from the first planar wall toward a third edge of the rung, and
• a fourth planar wall extending from the second planar wall toward the third edge of the rung,
• the tread portion, the first planar wall, the second planar wall, the third planar wall, and the fourth planar wall defining a cavity, at least one arcuate slot protruding from an interior surface of first wide rung and extending through the cavity along the length of the rung;
• wherein the at least one arcuate slot includes a first arcuate slot disposed adjacent to the first edge and a second arcuate slot disposed adjacent to the second edge and extending through the cavity along the length of the rung.

A rung for a ladder, the rung having a cavity bounded at least in part by an interior surface of the rung, the rung comprising:

• a first portion forming a standing surface, the first portion having a first edge and a second edge opposite and spaced from the first edge;
• a second portion coupled to the first portion to define the cavity, the second portion having a third edge disposed opposite the standing surface, the second portion including a first planar wall depending from the first portion adjacent to the first edge, a second planar wall depending from the first portion adjacent to the second edge, a third planar wall extending from the first planar wall toward the third edge, and a fourth planar wall extending from the second planar wall toward the third edge;
• a first arcuate slot disposed on the interior surface of the rung, the first arcuate slot positioned adjacent to the first edge;
• a second arcuate slot disposed on the interior surface of the rung, the first arcuate slot positioned adjacent to the second edge;
• and
• a third arcuate slot disposed adjacent to the third edge of the rung.