When the stepper rings, lubricating oil drips on the hydraulic rod. Due to dry weather or frequent use, the treadmill may make noise after being used for a period of time, which is normal. Treadmill can make gymnasts climb stairs repeatedly, which can not only enhance the function of cardiovascular system, but also fully exercise the muscles of thighs and calves. People who are bloated or new to treadmills often feel exhausted when doing strenuous exercise. There are two main types of treadmills, electronic treadmills and ordinary treadmills. Electronic treadmills are usually used in gymnasiums and health clubs. Using an engine to control the frequency of pedaling can reduce the negative impact of pedaling on leg joints.