Named after the Tortoise, this pose has a lot of significance in yogic literature. The fifth limb of Ashtanga Yoga as described by Patanjali is Pratyahara, which literally means fasting (of the senses). This is the stage when we draw our senses from outside to inside. This transition is perfectly represented by the analogy of a tortoise withdrawing its limbs and head from outside to inside the shell. This is also the significance in the transition from Kurmasana to Supta-Kurmasana. It is said that these poses are designed to create inner awareness and relaxation and therefore have the benefit of relieving stress and improving focus.
The analogy of the tortoise is quoted often in ancient texts. In the Bhagavad Gita, Lord Krishna says,” One who is able to withdraw the senses from their objects, just as a tortoise withdraws its limbs into its shell, is established in wisdom“