With this in mind, let's look at Ducati's competition at maximum revs, twice as high as their NASCAR counterparts. Much, much lighter and more sophisticated than NASCAR's pushrod valve trains, these valves, springs, and tappets are still operating very close to their limits. At or near the point at which valve toss occurs, the stored energy of the springs cannot act to rotate the cam, because the parts are unweighted. The parts come together with the tappet farther down the face of the cam, where the spring force is less effective at rotating the cam. The system must still use power to open the valve, but it gets less power back from the spring. Meanwhile, the desmo engine needn't work to compress the spring in the first place, though it does use some power to close the valve.