Abstract
Muscles attach to bones via tendons that stretch and recoil, affecting muscle force generation and metabolic energy consumption. In this study, we investigated the effect of tendon compliance on the metabolic cost of running using a full-body musculoskeletal model with a detailed model of muscle energetics. We performed muscle-driven simulations of running at 2–5 m/s with tendon force–strain curves that produced between 1 and 10% strain when the muscles were developing maximum isometric force. We computed the average metabolic power consumed by each muscle when running at each speed and with each tendon compliance. Average whole-body metabolic power consumption increased as running speed increased, regardless of tendon compliance, and was lowest at each speed when tendon strain reached 2–3% as muscles were developing maximum isometric force. When running at 2 m/s, the soleus muscle consumed less metabolic power at high tendon compliance because the strain of the tendon allowed the muscle fibers to operate nearly isometrically during stance. In contrast, the medial and lateral gastrocnemii consumed less metabolic power at low tendon compliance because less compliant tendons allowed the muscle fibers to operate closer to their optimal lengths during stance. The software and simulations used in this study are freely available at simtk.org and enable examination of muscle energetics with unprecedented detail.
Citation: Uchida TK, Hicks JL, Dembia CL, Delp SL (2016) Stretching Your Energetic Budget: How Tendon Compliance Affects the Metabolic Cost of Running. PLoS ONE 11(3):
e0150378.
https://doi.org/10.1371/journal.pone.0150378
Editor: Amir A. Zadpoor,
Delft University of Technology (TUDelft), NETHERLANDS
Received: September 16, 2015; Accepted: February 12, 2016; Published: March 1, 2016
Copyright: © 2016 Uchida et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: OpenSim is an open-source software platform for modeling and simulation of movement, and is freely available at https://simtk.org/home/opensim and on GitHub at https://github.com/opensim-org/opensim-core. The muscle energetics model used in this study is available in OpenSim 3.3; a plug-in for use with OpenSim 3.2 is available at https://github.com/opensim-org/opensim-metabolicsprobes. The analyses performed in this study were based on simulations originally generated by Hamner and Delp (2013), which are freely available at https://simtk.org/home/nmbl_running. The data underlying the findings of this study are freely available at https://simtk.org/home/metabolics_run.
Funding: Funding was provided to all authors by Defense Advanced Research Projects Agency (DARPA) contract W911QX-12-C-0018 (Warrior Web) and by National Institutes of Health (NIH) grants R24 HD065690 and P2C HD065690 (NIH National Center for Simulation in Rehabilitation Research), U54 EB020405 (Mobilize Center NIH Big Data to Knowledge Center of Excellence), and U54 GM072970 (NIH National Center for Physics-Based Simulation of Biological Structures). CLD also received funding from National Science Foundation (NSF) Graduate Research Fellowship DGE-114747. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
Description
This study investigates how tendon compliance affects the metabolic cost of running.