Shoulders Shoulders play an important role in keeping your upper body relaxed while you run, which is critical to maintaining efficient running posture.

当您在奔跑时，肩膀对保持您上半身的松弛非常重要，保持上半身的松弛又是维持高效率跑步姿势的关键。

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"Our study shows that the heel-down posture increases the economy of walking but not the economy of running, " says Carrier.

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