If this exercise is too easy, let your hips go down until your leg is totally flexed, you can also wear a backpack and try again, or just go ahead next step.

• 如果这个对你来说轻而易举的话，可以试著把屁股坐得更低，直到腿完全弯曲为止，也可以背个背包再练习，或是直接跳到下一个步骤。