Sun salutation is not specifically a yoga posture, but instead is a series of movements which are typically done at the start of any yoga session, and are designed to increase flexibility and prepare the body for exercise. To perform sun salutations, start by standing tall in the center of your exercise mat with your feet planted firmly on the ground. Let your arms relax by your sides, and stretch your head towards the sky. Take a deep breath, and as you do so, create an arc with your arm, raising them over your head. As you exhale your breath, slowly bend from the waist, and drop your arms to the ground. Inhale again, and slowly step your right foot as far back on the mat as you can. Now exhale, and step your left foot back to meet it. You should now be in the push up position. Carefully bend your elbows, and lower your entire body to the ground. Inhale deeply, and lift just your chest off the ground. As you exhale, curl your toes under, and push your hips into the air, so your body is forming a triangle. Finally, take one last deep breath, and step your right foot to your hands. Exhale, and step your left foot to your hands. Slowly lift your chest towards the sky, coming to a standing position. As you do this, raise your arms back to their original overhead position. Slowly lower them back down to your sides. This is considered one cycle of sun salutations. Do as many cycles as you feel necessary to prepare yourself for your yoga session.