Finally, slow down to 40 rpms or less for about five minutes.

最后，将速度降到每分钟四十转或少于四十转，持续约五分钟。

Then increase your pace to 60 rpms and hold it steady for about 20 minutes.

然后逐渐增加到每分钟六十转，并以此速度持续踩二十分钟。

On the flip side, diesel engines are bulky, and typically consist of longer piston strokes, so they can't reach high RPMs without incurring a lot of mechanical strain.

另一方面，柴油发动机体积庞大，通常由更长的活塞冲程组成，因此它们无法在不产生很大机械应变的情况下达到高转速。

On its face, this one is terrifying, and admittedly being slowly lowered into a cylinder with a sharpened metal coil spinning at several hundred rpms is good reason to wet yourself.

从表面上看，这个是可怕的，而且不可否认，慢慢地下降到一个圆柱体中，圆柱体上有一个以数百转/分的速度旋转的锋利的金属线圈是弄湿自己的充分理由。