So, the action of extending the leg backward creates a forward and upward movement (the flight phase).

因此，腿向后伸展的作用力，产生一个向前向上的运动(腾空阶段)。

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The flight phase: As an athlete moves through the air, his leg swings backward and then moves rapidly forward.

腾空阶段：当运动员在空中移动之时，他的腿先向后摆动，然后迅速向前移动。

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The flight phase: As an athlete moves through the air, his leg swings backward and then moves rapidly forward.

腾空阶段：当运动员在空中移动之时，他的腿先向后摆动，然后迅速向前移动。

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