STANDING FORWARD BEND - PADA HASTHASANA
Definition: Bending forward in a standing position.
Standing poses develop strength and flexibility in your legs and hips and equilibrium in your body. The Hands-to-Feet Pose stretches your spine and joints, and increase the blood supply to your brain. The Triangle is the last of the basic Asanas. You must master this pose and its variations before trying the advanced Asanas.
Objective: To make your spine and legs supple and strong.
FORWARD & DOWN
This is similar to the Forward Bend, but here gravity helps to stretch your body down. Stand with your feet together. Inhale, while lifting your arms straight above your head. Exhale as you bend forward and down. Breathe normally while you are in the pose. Hold for at least 30 seconds: as you gain experience, increase the time to several minutes.
NASM lists this as dangerous potentially.
Possibly placing the vertebrae and cartilage discs in low back under high stress. Not for those with history of herniated discs or nerve pain that runs in the back of the leg. Advises not to hyperextend the knees placing high stress on ligaments of the knee.
Again NASM text tells what not to do, but does not offer cues for doing this pose properly.