Logo image
Back
Leg compliance is required to explain the ground reaction force patterns and speed ranges in different gaits
Journal article   Open access   Peer reviewed

Leg compliance is required to explain the ground reaction force patterns and speed ranges in different gaits

Ali Tehrani Safa, Tirthabir Biswas, Arun Ramakrishnan and Vikas Bhandawat
Royal Society Open Science, v 12(10), 250527
Oct 2025
DOI: https://doi.org/10.1098/rsos.250527
PMID: 41103767
url
https://doi.org/10.1098/rsos.250527View
Published, Version of Record (VoR) Open

Abstract

Locomotion Organismal And Evolutionary Biology Spring-Loaded Inverted Pendulum Walking
Two simple models—vaulting over stiff legs and rebounding over compliant legs—are employed to describe the mechanics of legged locomotion. It is agreed that compliant legs are necessary for describing running, and that leg compliance is also present during walking. Stiff legs continue to be employed to model walking under the assumption that the compliance of the leg during walking is low enough to be considered stiff. Here we study gait choice and walk-to-run transition in a biped with compliance and show that the principles underlying gait choice and transition are completely different from stiff legs. Two findings underpin our conclusions: First, at the same speed, step length and stance duration, multiple gaits that differ in the number of times the leg expands and contracts during a single stance are possible. Among them, humans and other animals choose the (normal) gait with M-shaped vertical ground reaction forces (vGRF) not just because of energy considerations but also constraints from forces. Second, the transition from walking to running occurs because of three factors: vGRF minimum at mid-stance characteristic of normal walking, synchronization of horizontal and vertical motions during single support, and velocity redirection during the double support. The insight above required an analytical approximation of the double spring-loaded pendulum (DSLIP) model describing the intricate oscillatory dynamics that relate single and double support phases. Additionally, we also examined DSLIP as a quantitative model for locomotion and conclude that DSLIP speed range is limited. However, insights gleaned from the analytical treatment of DSLIP are general and will inform the construction of more accurate models of walking.

Metrics

6 Record Views

Details

InCites Highlights

Data related to this publication, from InCites Benchmarking & Analytics tool:

Collaboration types
Domestic collaboration
Web of Science research areas
Biology
Logo image