Compare Dvipāda Pīṭham and Śalabhāsana in relation to their potential within the following situations:
1. In strengthening the leg muscles.
2. Potential stress on the sacroiliac joint.
3. Influencing the circulation.
4. Potential risk on the knees.
5. As a preparation for Dhanurāsana.
6. In helping with flat feet.
7. In improving the inhalation.
8. In decreasing lower back pain.