Calisthenics (American English) or callisthenics (British English) (/ˌkælɪsˈθɛnɪks/) is a form of strength training consisting of a variety of movements that exercise large muscle groups (gross motor movements), such as standing, grasping, pushing, etc. These exercises are often performed rhythmically and with minimal equipment, as bodyweight exercises. They are intended to increase strength, fitness, and flexibility, through movements such as pulling, pushing, bending, jumping, or swinging, using one's body weight for resistance. Calisthenics can provide the benefits of muscular and aerobic conditioning, in addition to improving psychomotor skills such as balance, agility, and coordination. A study done in 2017," The effects of a calisthenics training intervention on posture, strength and body composition", by a group of scientists who found that calisthenics training is an "effective training solution to improve posture, strength and body composition without the use of any major training equipment". Urban calisthenics is a form of Street Workout; calisthenics groups perform exercise routines in urban areas. Individuals and groups train to perform advanced calisthenics skills such as muscle-ups, levers, and various freestyle moves such as spins and flips. Sports teams and military units often perform leader-directed group calisthenics as a form of synchronized physical training (often including a customized "call and response" routine) to increase group cohesion and discipline. Calisthenics is also popular as a component of physical education in primary and secondary schools over much of the globe. In addition to general fitness, calisthenics exercises are often used as baseline physical evaluations for military organizations around the world. For example, they are used in the U.S. Army Physical Fitness Test and the U.S.M.C. Physical Fitness Test.