The leg to be stretched should be positioned behind your trunk with your knee bent.

要伸展的那条腿应该放在躯干的后面并弯曲膝盖。

《柯林斯英汉双解大词典》

Exhale, keep knee bent and lower left leg until toe touches floor.

呼气，保持膝关节弯曲并且下放左腿直到脚尖接触地面。

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Straight leg Raises - Lie on your back with one leg straight and one knee bent.

伸直抬腿——平躺，一条腿伸直，另一条腿膝盖弯曲。

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