Side plank pose increases balance while toning the abdomen (especially the side) and strengthening the legs and arms. It stretches and strengthens the wrist and can help prepare practitioners for more advanced arm-balancing poses. This posture is often considered one of the best poses for strengthening the abdominal muscles, which can assist in improving posture as well as protecting the spine over time.
Side plank pose's Sanskrit synonym, vasisthasana, means "best" or "wealthy" pose. In Hinduism, Vasistha was a saint who possessed a divine cow and her children could grant whatever their owners wished, which made Vasistha wealthy. Likewise, side plank pose can help the practitioner feel powerful and confidently wealthy as he/she notices his/her balance and abdominal strength improving over time.