Gait is one of the most basic movements, and walking activity accomplished in dual task conditions realistically represents daily life mobility. Much is known about diurnal variations of gait components such as muscle power, postural control, and attention. However, paradoxically only little is known about gait itself. The aim of this study was to analyze whether gait parameters show time-of-day fluctuation in simple and dual task conditions. Sixteen young subjects performed sessions at five specific hours (06:00, 10:00, 14:00, 18:00 and 22:00 h), performing a single (walking or counting) and a dual (walking and counting) task. When performing gait in dual task conditions, an additional cognitive task had to be carried out. More precisely, the participants had to count backwards from a two-digit random number by increments of three while walking. Spatio-temporal gait parameters and counting performance data were recorded for analysis. Walking speed significantly decreased, while stride length variability increased when the task condition switched from single to dual. In the single-task condition, diurnal variations were observed in both walking speed and counting speed. Walking speed was higher in the afternoon and in the evening (14:00 and 22:00 h) and lower in the morning (10:00 h). Counting speed was maximum at 10:00 and 14:00 h and minimum at 18:00 h. Nevertheless, no significant diurnal fluctuation was substanytiated in the dual task condition. These results confirm the existing literature about changes in gait between single and dual task conditions. A diurnal pattern of single-task gait could also be highlighted. Moreover, this study suggests that diurnal variations faded in complex dual task gait, when the cognitive load nearly reached its maximum. These findings might be used to reduce the risk for falls, especially of the elderly.

步态是最基本的运动之一，在双重任务条件下完成的步行活动实际上代表了日常生活的活动性。关于步态成分的昼夜变化，例如肌肉力量，姿势控制和注意力，已为人们所知。然而，自相矛盾的是，关于步态本身知之甚少。这项研究的目的是分析在简单和双重任务条件下步态参数是否显示时间波动。16名年轻受试者在五个特定时间（06：00、10：00、14：00、18：00和22:00 h）进行了会话，分别执行了一次（步行或计数）和双重（步行和计数）任务。当在双重任务条件下执行步态时，必须执行额外的认知任务。更准确地说，参与者在步行时必须从两位随机数开始倒数，每次递增三。记录时空步态参数和计数性能数据以供分析。当任务条件从单重变为双重时，步行速度显着降低，而步长可变性增加。在单任务条件下，步行速度和计数速度均出现日变化。下午和晚上（14:00和22:00 h）的步行速度较高，早晨（10:00 h）的步行速度较低。计数速度在10:00和14:00 h达到最大值，在18:00 h达到最小值。然而，在双重任务条件下，没有明显的昼夜波动。这些结果证实了有关单任务和双任务条件之间步态变化的现有文献。单任务步态的昼夜模式也可以突出显示。此外，这项研究表明，当认知负荷几乎达到最大时，昼夜变化在复杂的双重任务步态中消失。这些发现可用于降低跌倒的风险，尤其是对于老年人而言。