Unfortunately, 3D printed plastic was not strong enough to be used a drive shaft, so these parts were replaced with carbon-fiber components. The legs themselves are made fiberglass, with ripstop nylon being used for the flexible parts. This currently seems to be the optimal setup for avoiding breaking during running, though the scientists argue that there is no reason why higher speeds cannot be attained if they can discover new materials. Balance isn’t a problem either, as an aerodynamic stabilizer is used to keep it running straight.
Now you might wonder what the point is of an uncontrollable robot that just runs in a straight line, but two things are certain: the results are definitely impressive and it’s always good to know where your limits are.