The swing kick half turn is a good balance drill.  The goal is to perform a high front kick  and swing the same leg back while raising the support leg in a tall releve.  The gymnast performs a half turn ending with that same free leg raising up as high as possible above the horizontal line.  The whole drill must be performed without bending the support leg or the free swinging leg.   The body is kept straight without leaning forward or arching back.