Ubhaya = Both · Pada = Foot · Angusta = Big Toe · Asana = Pose
Tones your abdomen; applies acupressure to your big toes (which relate to head and brain health in Chinese reflexology).
In my tradition of practice (Ashtanga), there is a ready-made safety net called tristhana, or the three supports of the practice. They go from gross to subtle. The first support is what you do with your physical body: Keep your body still (resist fidgeting) but stay muscularly active where the pose requires it. Your body should be alert and fully engaged, but not rigid or gripped. This type of physical activation will allow your body to remain receptive to the dynamic movement of your breath within your body.
This conscious, purposeful breath is the second support and focuses on the energetic body: Breathe through your nose, making a gentle sound in your throat and chest. Breathe freely into the entirety of your rib cage, while gently lifting from the center of your pelvic floor and the lowest part of your belly.
The third support is how you choose to direct your attention: Keep your eyes open and your gaze soft and steady. By tempering the physical effort with the energetic practice of breath and the mental and emotional practice of gaze (attention), you’ll minimize the overdoing or overreaching that is created through striving. Receive your practice as it is, and focus on the sending and receiving of energy and the gift of your attention—the aspects of practice that have a more lasting effect on the quality of your life. Take your time and be patient.
See also Challenge Pose: Mayurasana