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.
Whether it is a mechanical, hydraulic, flat tappet or roller style, the lifter is one of the most important components in the engine. The lifter technology determines how the camshaft will react to the rest of the engine combination. And the technology that goes into it is simply amazing.