Weight vests are becoming a very popular form of adding weight around the entire core to, for the most part, simulate the fat storage areas of the human body. It is very useful for adding weight to limb-centric movements, and for handling great weights. Due to the large area available, it can also handle more weight. If well-affixed, it is the safest most natural means of mimicking added body mass without unbalancing the body's muscles. They can be used to add resistance to almost any whole-body movement. A study has shown that using a weighted vest can increase the metabolic costs, relative exercise intensity, and loading of the skeletal system during walking.