@article {69624,
	title = {Leg compliance is required to explain the ground reaction force patterns and speed ranges in different gaits},
	journal = {bioRxiv},
	year = {2024},
	month = {2024 Sep 24},
	abstract = {<p>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 legs are compliant while walking. Despite this agreement, stiff legs continue to be employed to model walking. Here, we show that leg compliance is necessary to model walking and, in the process, identify the principles that underpin two important features of legged locomotion: First, at the same speed, step length, and stance duration, multiple gaits that differ in the number of leg contraction cycles are possible. Among them, humans and other animals choose a gait with M-shaped vertical ground reaction forces because it is energetically favored. Second, the transition from walking to running occurs because of the inability to redirect the vertical component of the velocity during the double stance phase. Additionally, we also examine the limits of double spring-loaded pendulum (DSLIP) as a quantitative model for locomotion, and conclude that DSLIP is limited as a model for walking. However, insights gleaned from the analytical treatment of DSLIP are general and will inform the construction of more accurate models of walking.</p>
},
	doi = {10.1101/2024.09.23.612940},
	url = {https://doi.org/10.1101/2024.09.23.612940},
	author = {Safa, Ali Tehrani and Biswas, Tirthabir and Ramakrishnan, Arun and Bhandawat, Vikas}
}
@article {66027,
	title = {Drosophila uses a tripod gait across all walking speeds, and the geometry of the tripod is important for speed control.},
	journal = {eLife},
	volume = {10},
	year = {2021},
	month = {2021 Feb 03},
	abstract = {<p>Changes in walking speed are characterized by changes in both the animal{\textquoteright}s gait and the mechanics of its interaction with the ground. Here we study these changes in walking . We measured the fly{\textquoteright}s center of mass (CoM) movement with high spatial resolution and the position of its footprints. Flies predominantly employ a modified tripod gait that only changes marginally with speed. The mechanics of a tripod gait can be approximated with a simple model - angular and radial spring-loaded inverted pendulum (ARSLIP) - which is characterized by two springs of an effective leg that become stiffer as the speed increases. Surprisingly, the change in the stiffness of the spring is mediated by the change in tripod shape rather than a change in stiffness of the individual leg. The effect of tripod shape on mechanics can also explain the large variation in kinematics among insects, and ARSLIP can model these variations.</p>
},
	issn = {2050-084X},
	doi = {10.7554/eLife.65878},
	author = {Chun, Chanwoo and Biswas, Tirthabir and Bhandawat, Vikas}
}
