Eka pada viparita dandasana is the more strenuous asana or pose than dwi pada viparita dandasana.
How does it affect the body? The abdominal muscles, says B. K. S. Iyengar, are exercised and the spine is toned. As the bending ia more strenuous, the effect is correspondingly greater.
Yet, for those with lower back pain or any issues with spine ot heart, this could be way too perilous and not worth the risk. Do not try this without an experienced professional yoga guru.