标题： 现实中的地面行走过渡不是尖锐的，而是根据能量最优性逐渐变化的走跑混合模式 显示英文标题

标题： Realistic overground gait transitions are not sharp but involve gradually changing walk-run mixtures as per energy optimality

摘要： 人类使用两种定性不同的步态进行运动，即步行和跑步——通常在较低速度时使用步行，在较高速度时使用跑步。 研究人员已经研究了人类在跑步机上在步行和跑步之间切换的时间，并注意到这些步态转换速度存在滞后现象。 在这里，我们考虑了一个生态上现实的地面运动任务，该任务要求在规定的时间内完成一段较长的距离（800米或2400米）。 与跑步机不同，此任务允许人类在试验过程中改变速度或步态以按时到达目的地：这个任务类似于从办公室到另一个办公室去参加会议，既不能早到也不能迟到。 我们发现，步态转换并不是尖锐的，而是涉及一个“步态转换区域”，在此区域内人类会混合使用步行和跑步，低速时主要步行，高速时主要跑步——这支持了之前在短距离（120米）上的结果。 这种逐渐变化的步行-跑步混合模式是由能量最优性预测的。 我们假设，在这种现实的地面条件下，这种能量最优行为解释了跑步机实验中的滞后行为，似乎比能量最优性预测的切换时间更早。 显示英文摘要

摘要： Humans use two qualitatively different gaits for locomotion, namely, walking and running -- usually using walking at lower speeds and running at higher speeds. Researchers have examined when humans switch between walking and running on treadmills and have noted hystereses in these gait transition speeds. Here, we consider an ecologically realistic overground locomotion task, one requiring traveling a given long distance (800 meters or 2400 meters) in a prescribed time duration. Unlike on a treadmill, this task allows the human to change speed or gait during the trial to reach the destination on time: this task is akin to traveling to an appointment at a particular time from your office to another office, arriving neither early or late. We find that gait transition is not sharp, but instead involves a 'gait transition regime' in which humans use a mixture of walking and running, using mostly walking atlower speeds and mostly running higher speeds -- supporting earlier results over short distances (120 m). The presence of this gradually changing walk-run mixture is predicted by energy optimality. We hypothesize that this energy optimal behavior in this realistic overground conditions accounts for the hysteretic behavior in treadmill experiments, apparently switching earlier than predicted by energy optimality.