Because of its dynamism and excitement , with 220 member countries that are a part of the FIVB ( Federation Internationale de Volleyball – International Volleyball Organization ) , volleyball has become one of the most popular sports in the world . Non-professional volleyball being played in leisure has metabolic equivalent of 3-4 METs , which falls into the category of moderate physical activity , while any professional volleyball,in the gym or on the sand, has metabolic equivalent of 8 METs , which tells us how it can be played in professional purposes ,as well in terms of recreation and preservation of health . It is an ideal model of health – oriented physical activity because it improves the function of the cardiorespiratory system , reduces the risk of metabolic syndrome and associated cardiovascular disease . In today's sedentary lifestyle , when about 35 % of the population is overweight , it is very important in the fight against obesity . It is believed that it increases the antioxidant response of the organism , and in the long-term reduces the inflammatory response . Particularly significant is it's effect on postmenopausal women , in which volleyball reduces the risk of osteoporosis , and in earlier age when it improves the structure of the skeletal system and motor skills . In persons with disabilities is of great importance because it increases selfconfidence, interaction , social integration , and raises overall quality of life.Sitting volleyball has recently found its place in Croatia ,where it tries to integrate a large number of persons with disabilities from the Croatian war of Independence.