Feet; intentionally placed, stable stance, weight spread throughout, press down, arches lifted.
Knees; extended, without locking out, lifted, thighs strong.
Hips; depending on foot position and individual, internally rotated or neutral alignment.
Spine; neutral, find length & gentle support.
Shoulders; neutral, gently drawing back and down.
Hands; fingers reaching down.
Tadasana isn't just about standing at the front of the mat. Tadasana translated : (‘Tada’ = mountain, 'asana' pose) implies a pose where one stands firm and erect as a mountain, so there is a level of engagement required throughout the body. The feet firmly rooted, arches lifted, legs strong, core slightly engaged, head lifted, shoulders drawing down, arms strong. This pose encourages a good upright posture all round, and can help restore foot strength and adaptability. It can also help a students confidence taking a stance displaying strength and openness.
This pose is useful as a starting reference for you as a teacher or the student to observe on return. Tadasana can be seen as a foundation pose or set up for any other standing pose including balances. It can also be used to find stillness before or in between standing sequences.
There shouldn't be any reason your student can't do this pose if they are attending a vinyasa flow session.
Foot to Hip - Inward/outward rotation. Widen/narrow stance.
Pelvis - Tilt forward & back.
Spine - Cat Cow. Side bends. Twist.
Shoulder to Hand - Elevate/depress shoulders. Rotate arms.
Close eyes / tip toe to challenge balance.