If you're talking human size bipeds, if they have the required peak torques and speeds on the leg actuators to work at all, they will have the physical ability to sprint. You can think of a Segway to visualize this more easily - the motor on it needs quite a bit of power and speed to overcome a human leaning forward drastically without just falling over, a biped is the same thing with more steps. You need quite a lot of power to even idle stand a biped and a lot of speed to even do tiny corrections. If you want to rely on an ifElse statement or a model policy to not sprint, then you just introduce more likelihood of falling over, which also isn't great around humans. If you truly want to know a robot will not (meaning cannot) sprint, you would need form factors like a worm or centipede.

Sprinting requires significantly different physical form than just bigger motors. I do not accept the claim that humans couldn't possibly make bipedal robots that can reliably walk without being able to sprint. That's absurd.