Am I able to use a stair stepper or walk uphill on a treadmill to achieve these "climbing feet"?
I am afraid it won't work, since you need that either the barometric altimeter, or the GPS records the required Elevation Gain. You can achieve it both running true stair scales indoors or outdoors (or just slopes), but you have to watch out that your altimeter records the elevation gain correctly. The pressure sensor is typically relatively slow, and easily clogs with sweat or dirt, so it is safer adding the elevation field on the Floor Climbing screen, and keeping an eye on it, to avoid a bad surprise at the end. Doing it outdoors with GPS enabled is wiser, since you can use the Elevation Correction in the case the barometric altimeter misfunctions.
