当你的双手放回到腿上时，你上臂的中线应该和你身体的中线对齐。

When your hands are on your thighs, the median line of your upper inner arms should align with the median line of of the sides of your torso.

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同时，手在划水的过程中应该沿着身体的中线运动，并且处于持续加速状态。

Meanwhile, the hand should travel directly under the centerline of the body and accelerate throughout the stroke.

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在手和臂入水后，仍继续在头前沿着身体的中线延伸。 向后推臂的动作从在前方抓（抱）水开始，然后向下向后推至身体的中线，这时划水的手臂几乎要碰到自己的腹部。

He continue to extend his hand and arm after they enter the water, upstretch in front of his head, along the center line of his body.

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