杆头的轨道由内向外挥，最后又回到内侧来的英文

inside to inside

• 杆:    shaft; rod; bar
• 头:    5点就得动身 have to sta ...
• 的:    4次方是 The fourth po ...
• 轨道:    track; pathway; ra ...
• 由:    cause; reason
• 内向:    introversion
• 外:    outside; external ...
• 挥:    wave; wield
• 最后:    last; final; ultim ...
• 内:    inner; inside; wit ...
• 侧:    slant; sloping
• 来:    come; arrive