The Floor Spikes are a special case of the Spike Trap. They occur in many of the Tomb Raider games.
Tomb Raider Classic
In some cases to avoid getting hurt, Lara can walk through the spikes and emerge unscathed. But if she falls in the spikes, Lara will instantly die as the spikes impale her.
Lara Croft: Relic Run
In Lara Croft: Relic Run, the floor spikes retract and extend in regular intervals. That doesn't mean however that it is safe to run through them. Running through or jumping into them is always deadly. The best method to conquer them is to either avoid them by changing lanes or by jumping over them with perfect timing.