This 25 minute video is a tutorial on the preparatory poses for getting ready for chaturanga dandasana, a common transition pose used in vigorous vinyasa practices. Chaturanga requires lots of strength in the upper back, triceps, and core. Alignment is super important in chaturanga, and if done improperly, you can put a lot of strain on your shoulders and end up with shoulder pain and injury. Therefore, as emphasized in the video, it is imperative to keep the elbows back toward the hips and shoulders/shoulderblades plugging down the back. This keeps the collarbones wide, preventing shoulders from rolling forward (as they do in a traditional push-up with elbows out), and risking compression of the shoulder joint space. Also, note body stays straight as a plank, so avoid letting your shoulders fall below the torso and avoid letting your hips drift up. Remember, go slow and progress at your own pace. Start with just a few breaths in each of the prep poses, and then work up slowly before you even start trying to lower down into chaturanga. Build the strength to do the pose properly and you will avoid injury and gain all of the benefits!