Department of Kinesiology, University of Massachusetts Amherst, Amherst, MA, USA.
Department of Kinesiology, The University of Alabama, Tuscaloosa, AL, USA.
Hum Mov Sci. 2023 Aug;90:103117. doi: 10.1016/j.humov.2023.103117. Epub 2023 Jun 17.
Humans naturally transition from walking to running at a point known as the walk-to-run transition (WRT). The WRT commonly occurs at a speed of ∼2.1 m/s (m/s) or a Froude number (dimensionless value considering leg length) of 0.5. Emerging evidence suggests the WRT can also be classified using a cadence of 140 steps/min. An accurate cadence-based WRT metric would aid in classifying wearable technology minute-level step metrics as walking vs. running.
To evaluate performance of 1) WRT predictors directly identified from a treadmill-based dataset of sequentially faster bouts, and 2) accepted WRT predictors compiled from previous literature.
Twenty-eight adults (71.4% men; age = 36.6 ± 12.8 years, BMI = 26.2 ± 4.7 kg/m) completed a series of five-minute treadmill walking bouts increasing in 0.2 m/s increments until they freely chose to run. Optimal WRT values for speed, Froude number, and cadence were identified using receiver operating characteristic (ROC) curve analyses. WRT value performance was evaluated via classification accuracy metrics.
Overall accuracies (metric, percent) according to WRT predictors from previous literature were: speed (2.1 m/s, 55.0%), Froude number (0.5, 76.8%), and cadence (140 steps/min, 91.1%), and those from the dataset herein were: speed (1.9 and 2.0 m/s, 78.6%), Froude number (0.68, 77.3%), and cadence (134, 139, and 141 steps/min, 92.9%). The three equally accurate cadence values support a heuristic range of cadence-based WRT values in young and middle-aged adults: 135-140 steps/min.
A tight range of cadence values performed better as WRT predictors compared to either previously reported or directly identified speed or Froude number values. These findings have important implications for gait classification, especially considering cadence is a simple metric which can be readily assessed across settings using direct observation or wearable technologies.
人类在行走向奔跑的转变点（WRT）自然会从行走过渡到奔跑。WRT 通常发生在速度约为 2.1m/s（m/s）或弗劳德数（考虑腿长的无量纲值）为 0.5 的情况下。新出现的证据表明，WRT 也可以使用 140 步/分钟的节奏进行分类。准确的基于节奏的 WRT 度量标准将有助于将可穿戴技术的分钟级步速指标分类为行走与跑步。
评估以下两种方法的性能：1）直接从基于跑步机的连续加速阶段数据集识别的 WRT 预测因子，以及 2）从以前的文献中综合的公认的 WRT 预测因子。
28 名成年人（71.4%为男性；年龄=36.6±12.8 岁，BMI=26.2±4.7kg/m2）完成了一系列五分钟的跑步机行走，每次增加 0.2m/s，直到他们自由选择跑步。使用接收者操作特征（ROC）曲线分析确定速度、弗劳德数和节奏的最佳 WRT 值。通过分类准确性指标评估 WRT 值的性能。
根据以前文献中的 WRT 预测因子，总体准确率（以百分比表示）如下：速度（2.1m/s，55.0%）、弗劳德数（0.5，76.8%）和节奏（140 步/分钟，91.1%），以及本文数据集中的预测因子：速度（1.9 和 2.0m/s，78.6%）、弗劳德数（0.68，77.3%）和节奏（134、139 和 141 步/分钟，92.9%）。三个同样准确的节奏值支持年轻和中年成年人基于节奏的 WRT 值的启发式范围：135-140 步/分钟。
与之前报道的或直接确定的速度或弗劳德数值相比，节奏值的紧密范围作为 WRT 预测因子表现更好。这些发现对步态分类具有重要意义，特别是考虑到节奏是一种简单的指标，可以使用直接观察或可穿戴技术在各种环境中轻松评估。
