Samasthiti comes from the Sanskrit root words sama, meaning “same,” “equal” or “upright,” and sthiti, meaning “to establish” or “to stand.”
In certain styles of yoga, samasthiti varies from tadasana. For example, in Vinyasa Krama Yoga, samasthiti is performed with the heels grounded, whereas tadasana is performed with the heels lifted, balancing on the toes. Other schools state that although the anatomical position is the same in both asanas, tadasana is a pose, while samasthiti is more of a command of attention, bringing you into the present moment.
Samasthiti is both physically and mentally a grounding pose, and can be used to cultivate a connection with the earth. It can be deepened by closing the eyes to challenge the balance further. In Ashtanga Vinyasa yoga, the drishti for samasthiti is the end of the nose, or nasagra drishti, which helps to make the pose more introspective.
All three bandhas - uddiyana, mula and jalandhara - can be engaged during samasthiti.