1. Noun, Suru verb

   headstand

   see 逆立ちsee さかだち・1

2. doing one's best; doing something to the best of one's ability

Also written 鯱立ち【しゃちほこだち】shachihokodachi、しゃっちょこ立ち【しゃっちょこだち】shacchokodachi