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 power and idle characteristics of a camshaft rated at a .006 lift point will be much different from one with the same rating at a .002 lift point. Many performance engine builders gauge a race profile's aggressiveness by looking at the duration at .020, .050 and .200.