Stability of running on rough terrain depends on the propagation of perturbations due to the ground. We consider stability within the sagittal plane and model the dynamics of running as a two-dimensional body with alternating aerial and stance phases. Stance is modelled as a passive, impulsive collision followed by an active, impulsive push-off that compensates for collisional losses. Such a runner has infinitely many strategies to maintain periodic gaits on flat ground. However, these strategies differ in how perturbations due to terrain unevenness are propagated. Instabilities manifest as tumbling (orientational instability) or failing to maintain a steady speed (translational instability). We find that open-loop strategies that avoid sensory feedback are sufficient to maintain stability on step-like terrains with piecewise flat surfaces that randomly vary in height. However, these open-loop runners lose orientational stability on rough terrains whose slope also varies randomly. The orientational instability is significantly mitigated by minimizing the tangential collision, which typically requires sensory information and anticipatory strategies such as leg retraction. By analysing the propagation of perturbations, we derive a single dimensionless parameter that governs stability. This parameter provides guidelines for the design and control of both biological and robotic runners.
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http://dx.doi.org/10.1098/rsos.181729 | DOI Listing |
J Microsc
January 2025
Ningbo Key Laboratory of Micro-Nano Motion and Intelligent Control, Ningbo University, Ningbo, PR China.
The types and quantities of microorganisms in activated sludge are directly related to the stability and efficiency of sewage treatment systems. This paper proposes a sludge microorganism detection method based on microscopic phase contrast image optimisation and deep learning. Firstly, a dataset containing eight types of microorganisms is constructed, and an augmentation strategy based on single and multisamples processing is designed to address the issues of sample deficiency and uneven distribution.
View Article and Find Full Text PDFFront Sports Act Living
January 2025
Sports Science Research Studies, Rey Juan Carlos University, Fuenlabrada, Madrid, Spain.
Introduction: The aim of this study was to evaluate the effect of an Athletic Performance Program (APP), implemented as a complement to the usual training routines of a professional football team, on match performance variables in professional football players. The APP was designed to target mobility, stability, strength, multidirectional and sprint skills, which are critical for performance during competitive matches.
Methods: A prospective quasi-experimental study was conducted over three consecutive seasons.
JMIR Aging
January 2025
Institute of Mathematics and Computer Sciences, University of São Paulo, São Carlos SP, Brazil.
Background: The prevalence of stroke is high in both males and females, and it rises with age. Stroke often leads to sensor and motor issues, such as hemiparesis affecting one side of the body. Poststroke patients require torso stabilization exercises, but maintaining proper posture can be challenging due to their condition.
View Article and Find Full Text PDFFront Public Health
January 2025
Department of Physical Education, Shandong Normal University, Jinan, China.
Introduction: This study aimed to systematically review the effects of different physical activity programs on the fundamental movement skills of 3 - 7-year-old children.
Methods: For this review, the databases of CNKI, Web of Science, and PubMed were searched to collect relevant literature on the effects of different physical activity program interventions on fundamental movement skills, and a total of 10 articles with 1,121 subjects were included. The Cochrane Risk of Bias Assessment Tool was used to assess the quality of the literature, and meta-analysis was performed using Review Manager 5.
Front Robot AI
January 2025
Research Institute of Electrical Communication, Tohoku University, Sendai, Japan.
This paper explores the applicability of bicycle-inspired balance control in a quadruped robot model. Bicycles maintain stability and change direction by intuitively steering the handle, which induces yaw motion in the body frame and generates an inertial effect to support balance. Inspired by this balancing strategy, we implemented a similar mechanism in a quadruped robot model, introducing a yaw trunk joint analogous to a bicycle's steering handle.
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