Taekwondo Kicking ?

Explain this kicking combination why are instructor has us do on the kicking bag roundhouse right leg slide roundhouse with the left foot. Explain why this kick is good to use. ANSWER TO THE ABOVE QUESTION There are different types of Taekwondo kicks such as the front snap kick, side piercing kick, roundhouse kick, reverse turning kick or the horse kick, spinning side kick, hook kick, axe kick, crescent kick, spin kicks, tornado kick or the 360 kick, jump kick, advanced kick and the fast kick.