utilizes a forced damped oscillation framework applied to a chain-link model of undulatory swimming to explore the relationship between forcing, deformation, and movement. It reveals a unified understanding of swimming, whether driven by muscle contractions (active swimming) or forces from the surrounding fluid (passive swimming). The research demonstrates that simple forcing patterns can elicit seemingly complex deformation kinematics that result in movement. The frequency of forcing relative to the natural frequency of the damped oscillator plays a significant role in determining emergent deformation characteristics. Furthermore, the proposed approach provides insights into optimal deformation kinematics for achieving high swimming speeds. These findings, based on a chain-link model, are supported by comprehensive computational fluid dynamics (CFD) simulations and shed light on prior literature regarding optimal stiffness for maximum speed. Animations showing a three-dimensional vortex wake behind the eel swimming with different kinematics. For more related content also check out "Refetch of..." below. The images and data used here are adapted from the work of: Amneet Pal Singh Bhalla, Boyce E. Griffith, Neelesh A. Patankar in the article titled '[A Forced Damped Oscillation Framework for Undulatory Swimming Provides New Insights into How Propulsion Arises in Active and Passive Swimming]' published in the journal [PLOS Computational Biology]. The source of the these can be found at [Link to the Source: https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1003097] . The images and data are licensed under CC BY 4.0 [License Link: https://creativecommons.org/licenses/by/4.0/]."