The piece of equipment called the BOSU is found in almost every gym. The acronym stands for “both sides utilized”. It has a blue rubber half circle on one side and a flat hard plastic surface on the other. It is used to challenge your proprioception and increase your balance by strengthening your stabilizing muscles. It can be used in many different exercises to increase the level of difficulty. It is also a popular physical therapy tool used to strengthen previously injured joints. You can use it with squats, push ups, ankle stability exercises, and much more.