Reclining Big Toe (Supta Pandangusthasana) – From corpse pose, bend first knee in toward torso while pressing the other leg downward to floor and its heel forward (ankle dorsiflexion); place strap under arch of first foot, holding strap with both hands; straighten the first knee; repeat with other leg.

http://facweb.northseattle.edu/troot/PEC298_Yoga_Pilates/yog...

I think it means bending the ankle so that the foot is at a right angle to the leg.

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Note added at 36 mins (2017-06-05 18:24:05 GMT)
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Ah, I forgot to mention that the person is lying down, not laying down.

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Note added at 48 mins (2017-06-05 18:36:03 GMT)
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Traditional Method. Lie supine on mat, flex involved hip, extend knee and dorsiflex ankle. Place strap around bottom of foot, or grab foot/big toe, and pull hip further into flexion. Common adjustments include teacher pushing student’s hip further into flexion and pushing opposite hip further into floor or student pulling herself further into passive ranges.

http://www.ideafit.com/fitness-library/yoga-fundamentals-pos...

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Note added at 57 mins (2017-06-05 18:44:51 GMT)
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It's just occurred to me that I don't know if the person is lying face up (supine position) or face down (prone position).

If the person is face down, then 'empinar el pie' would mean 'point the foot downwards/lift the heel'

Medical Definition of plantar flexion
: movement of the foot in which the foot or toes flex downward toward the sole—compare dorsiflexion

https://www.merriam-webster.com/medical/plantar flexion

i think is "Tilt the right foot" like bend the ankle