Calisthenics are exercises that use your own body weight to build strength, flexibility, and endurance. Instead of lifting dumbbells or using machines, you might do push-ups, pull-ups, sit-ups, jumping jacks, or squats.

What makes calisthenics special is that you can do them almost anywhere: in your bedroom, at a playground, or in a park. You don't need expensive equipment or a gym membership. Ancient Greek warriors used calisthenics to stay fit for battle, and military training today still relies heavily on these exercises.

When you do a pull-up, you're lifting your entire body weight with your arms and back. When you hold a plank position, every muscle from your shoulders to your legs works to keep you steady. Calisthenics teach your body to work as one coordinated system rather than focusing on individual muscles.

Schools often include calisthenics in physical education classes because they're effective and safe when done properly. Gymnasts, dancers, martial artists, and athletes in many sports use calisthenics as part of their training. The beauty of calisthenics is their simplicity: your body is the gym, and every workout makes you stronger.