Single whip is common in most styles of tai chi. It appears several times in the forms and is a good posture to hold for qigong practice. Single whip appears early in the form and repeated throughout.
Single whip is a useful self defence move and has multiple variations. Defending from a punch, grabbing the arm and striking their head can be quite effective.
The arms being raised and standing in a horse riding stance can provide health benefits to the heart and groin area.
Disclaimer: I am not a medical practitioner and you should always consult your doctor before undertaking any exercises.