Landing areas in the jumps are safety equipment first and facility furniture second. They are specified by dimension and by how they absorb a falling body, and they wear out on a schedule.
Why size is a safety specification
Athletes do not always land where the technique says they should, and a mistimed jump can send a body sideways or backward toward the edge.
Minimum dimensions exist so that an off-target landing still lands on padding rather than at a boundary or on the surface beyond it.
Pole vault pits are larger than high jump pits because the athlete arrives higher, faster and with more possible directions of failure.
The construction is layered on purpose
A pit is not a single block of foam. Softer top layers decelerate the body gently while firmer lower layers prevent bottoming out onto the base.
Get the mix wrong in one direction and the athlete sinks through to a hard stop; wrong in the other and the pit is too firm to absorb the landing.
The cover sheet holds the modules together and has to breathe, because air has to leave the foam as it compresses and return as it recovers.
Gaps between modules matter
Pits are assembled from separate units, and gaps between them are a genuine hazard because a limb can enter a gap during a landing.
Systems are therefore strapped together and covered with a single top pad that bridges the joints.
Weekly checks look for separation, because units drift apart from repeated landings and from being moved for other uses of the infield.
Foam degrades without looking degraded
Cell structure breaks down from repeated compression, and older foam recovers more slowly and absorbs less on each successive landing.
Moisture accelerates this. Pits left uncovered outdoors take on water, which both adds weight and destroys the foam from inside.
Nothing about this is visible from the outside, which is why manufacturers state service lives and facilities are expected to record installation dates.
Surroundings are part of the system
The area around a pit needs padding on any hard edges, including standards, uprights and the base structures that hold the crossbar.
Vault box collars pad the one place on a runway an athlete can land on concrete, and they are now standard rather than optional.
Facilities that treat the pit as the whole safety system usually have the surrounding hazards to prove otherwise, because the pit is the part that gets replaced.

