Seat belts aboard the Campbell
A seat belt was a harness designed to hold and protect a passenger of a vehicle in case of an accident or a sudden stop.
On NX-class starships following the destruction of the Xindi weapon, the captain's bridge command chair was fitted with slots for shoulder harness seat belts. (Star Trek: Enterprise fourth season)
As of 2164, twin-shoulder seat belts were featured on the bridge and in engineering aboard the Freedom-class USS Franklin. (Star Trek Beyond)
The USS Enterprise of the alternate reality featured twin-shoulder belts for times of gravity failure, though they – unlike those aboard the Franklin – were self-extending. (Star Trek Into Darkness)
Constitution-class starships were equipped with seat belts, which were employed in cases when there was a loss of gravity on the bridge. (TAS: "Once Upon a Planet")
Starfleet Type 15 shuttlepods were equipped with seat belts for all passengers. (TNG: "Power Play")
SS La Sirena had seat belts on all chairs on its bridge, for use during high-velocity atmospheric entry. (PIC: "Et in Arcadia Ego, Part 1")
The stage directions from the revised final draft script of TOS: "Balance of Terror" made a reference to the bridge of a Romulan Bird-of-Prey having "seat-harnesses" which snapped when the vessel, close to destruction, came under fire from the USS Enterprise.
A deleted scene from Star Trek Nemesis had the USS Enterprise-E's command chair being refitted with seat belts. Captain Picard was delightfully surprised at the upgrade, noting, "It's about time." The chair's design was used for Captain Archer's chair in the fourth season of Star Trek: Enterprise.