Stress on the stride: How treadmill walking reveals gait variability differences in children, young adults, and seniors?

Abstract

The assessment of gait variability is a valuable approach for characterizing an individual’s walking pattern over extended time scales. Variability parameters, such as the coefficient of variation, the Hurst exponent, and the Minkowski fractal dimension of the attractor, are influenced by factors like age, dual-task performance, and neurodegenerative conditions. Treadmill walking, a compact and widely used method, enables precise data collection when combined with measurement devices. However, differences between treadmill and overground variability raise questions about its applicability to real-life gait analysis. This study investigates how treadmill walking, as an external stressor, reveals gait variability differences among children, young adults, and seniors by analyzing the center of mass trajectory. Fifteen children (median age: 11 years), 24 young adults (median age: 22.5 years), and 16 seniors (median age: 60 years) participated. Variability was assessed using stride intervals and phase-space metrics. Results indicate that young adults demonstrate “optimal” gait variability, characterized by minimal coefficients of variation and maximal fractal dimension. In contrast, children and seniors exhibit less predictable and less complex gait patterns, with differences in Hurst exponents distinguishing these groups. These findings highlight the nontrivial integration of age, fear of falling, and neurological maturation in gait variability. Practical implications for rehabilitation and clinical assessments are discussed, underscoring the need for protocol standardization and cautious interpretation of treadmill-based variability data.