Jock itch (tinea cruris) is a fungus, the same one that causes athlete's foot and scalp ringworm. The groin area is the perfect place for the fungi to grow and cause a fungal infection because it is moist, warm and dark.
The camshaft lift is the resultant net rise of the valve from its seat. The farther the valve rises from its seat the more airflow can be provided, which is generally more beneficial. Greater lift has some limitations.
The crank will always move in a circle, moving the connecting rod in a smooth sine wave like motion. The power can flow in either direction. That is, the crankshaft can drive the connecting rod, or the connecting rod can drive the crankshaft. A camshaft has a cam follower that rides on the cam. The cam on the camshaft can have more than one lobe (high spot) on it, so it is possible for the cam follower to move back-and-forth (or up-and-down) more than once for each rotation of the camshaft.