53. Beck ON, Golyski PR, Sawicki GS “Adding carbon fiber to shoe soles may not improve running economy: a muscle level explanation“. Scientific Reports. (2020). Supplementary Material
52. Nuckols RW, Takahashi KZ, Farris DJ, Mizrachi S, Riemer R, Sawicki GS “Mechanics of walking and running up and downhill: A joint-level perspective to guide design of lower-limb exoskeletons“. PloS One. (2020). Supplementary Data Supplementary Material
51. Beck ON, Gosyne J, Franz JR, Sawicki GS “Cyclically producing the same average muscle-tendon force with a smaller duty increases metabolic rate“. Proceedings of the Royal Society B: Biological Sciences. (2020). Supplementary Data Supplementary Material
50. Krupenevich RL, Clark WH, Sawicki GS, Franz JR “Older adults overcome reduced triceps surae structural stiffness to preserve ankle joint quasi-stiffness during walking“. Journal of Applied Biomechanics. (2020).
49. Nuckols RW, Sawicki GS “Impact of elastic ankle exoskeleton stiffness on neuromechanics and energetics of human walking across multiple speeds“. Journal of NeuroEngineering and Rehabilitation. (2020). Supplementary Data Supplementary Information
48. Sawicki GS, Beck ON, Kang I, Young AJ “The exoskeleton expansion: Improving walking and running economy”. Journal of Neuroengineering and Rehabilitation. (2020).
47. Nuckols RW, Dick TJ, Beck ON, Sawicki GS “Ultrasound imaging links soleus muscle neuromechanics and energetics during human walking with elastic ankle exoskeletons”. Scientific Reports. (2020). Supplementary Data Supplementary Analysis Short Talk
46. Dick TJM, Punith LK, Sawicki GS “Humans falling in holes: adaptations in lower-limb joint mechanics in response to a rapid change in substrate height during human hopping”. J. Royal Soc. Interface. (2019). Supplementary Data Correction
45. Beck ON, Punith LK, Nuckols RW, Sawicki GS “Exoskeletons improve locomotion economy by reducing active muscle volume“. Exerc Sport Sci Rev. (2019).
44. Abbott E, Nezwek T, Schmitt DO, Sawicki GS “Hurry up and get out of the way!: Exploring the limits of muscle-based latch systems for power amplification”. Journal of Integrative and Comparative Biology. (2019).
43. Lewis MJ, Williams KD, Langley T, Jarvis LM, Sawicki GS, Olby N, “Development of a novel gait analysis tool measuring center of pressure for evaluation of canine chronic thoracolumbar spinal cord injury“. J Neurotrauma. (2019).
42. Lewek MD, Sawicki GS, “Trailing limb angle is a surrogate for propulsive limb forces during walking post-stroke“. Clinical Biomechanics. (2019).
41. McCain EM, Dick TJM, Giest TN, Nuckols RW, Lewek MD, Saul KR, Sawicki GS, “Mechanics and energetics of post-stroke walking aided by a powered ankle exoskeleton with speed-adaptive myoelectric control“. J Neuroeng Rehabil. (2019). Supplementary Data
40. Blau SR, Davis LM, Gorney AM, Dohse CS, Williams KD, Lim JH, Pfitzner WG, Laber E, Sawicki GS, Olby NJ, “Quantifying center of pressure variability in chondrodystrophoid dogs”. The Veterinary Journal. (2017).
39. Robertson BD, Sawicki GS “A benchtop biorobotic platform for in vitro observation of muscle-tendon dynamics with parallel mechanical assistance from an elastic exoskeleton “. J Biomech. Mar 21.(2017). Supplementary Methods
38. Rosario MV, Sutton GP, Patek SN, Sawicki GS, “Muscle-spring dynamics in time-limited, elastic movements “. Proc Biol Sci. Sep 14; 283(1838) (2016).
37. Danos N, Holt N, Sawicki GS, Azizi E, “Modeling age-related changes in muscle tendon dynamics during cyclical contractions in the rat gastrocnemius muscle”. J Appl Physiol (1985). Oct 1; 124(4): 1004-1012 Epub Aug 4 (2016).
36. Takahashi KZ, Gross MT, van Werkhoven H, Piazza SJ, Sawicki GS,“Adding stiffness to the foot modulates soleus force velocity behaviour during human walking “. Nat Sci Rep. Jul 15; 6:29870 (2016).
*35. Sawicki GS, Khan N, “A simple model to estimate plantarflexor muscle-tendon dynamics during walking with elastic ankle exoskeletons”. IEEE Trans Biomed Eng. May; 63(5):914-923. Epub 2015, Oct 15 (2016). Supplementary Methods Model Data Readme
*Invited submission to a special issue.
34. Huang H, Crouch DL, Liu M, Sawicki GS,Wang D,“A cyber expert system for auto-tuning powered prosthesis impedance control parameters”. Ann Biomed Eng. May; 44(5) 1613-24. Epub 2015, Sep 25. (2016).
33. Sawicki GS, Sheppard P, Roberts TJ, “Power amplification in an isolated muscle-tendon unit is load dependent”. J Exp Biol. Nov; 218(Pt22):3700-9. (2015).
32. Robertson BD, Sawicki GS,“Unconstrained muscle-tendon workloops indicate resonance tuning as a mechanism for elastic limb behavior during terrestrial locomotion”. Proc Natl Acad Sci USA. Oct 27; 112(43): E5891-8. (2015). Supplementary Text
31. Sawicki GS, Robertson BD, Azizi E, Roberts TJ, “Timing matters: Tuning the mechanics of a muscle-tendon unit by adjusting stimulation phase during cyclic contractions”. J Exp Biol. Oct; 218(Pt 19): 3150-9. Epub Jul 31. (2015).
30. Collins SH, Wiggin MB, Sawicki GS,“Reducing the energy cost of human walking using an unpowered exoskeleton“. Nature. Jun 11; 522(7555): 212-5. Epub Apr 1. (2015).
Advance Online Publication, SupplementaryText, Exoskeleton Walking Video, Clutch Function Video Supplementary Data
—Nature Press Release, Nature Podcast,
—NCSU Press Release, NCSU PoWeR Lab Promo Video, Sawicki – CMU RoboticsInstitute Lecture, NIH Press Release
—CMU Press Release, CMU Exp. Biomechatronics Lab Promo Video, Add’tl Carnegie Mellon Media Materials, NSF Press Release
29. Takahashi KZ, Lewek MD, Sawicki GS, “A neuromechanics-based powered ankle exoskeleton to assist walking post-stroke: A feasibility study”. J Neuroeng Rehabil. Feb 25;12:23 (2015).
28. Farris DJ, Hampton AS, Lewek MD, Sawicki GS, “Revisiting the mechanics and energetics of walking in individuals with chronic hemiparesis following stroke: From individual limbs to lower-limb joints”. J Neuroeng Rehabil. Feb 27; 12(1): 24 (2015).
27. Mahon C, Farris DJ, Sawicki GS, Lewek MD, “Individual limb mechanical analysis of gait following stroke”. J Biomech. Apr 12; 48(6): 984-9. (2015).
*26. Zelik K, Takahashi KZ, Sawicki GS, “Six degree-of-freedom analysis of hip, knee, ankle and foot provides updated understanding of biomechanical work during human walking”. J Exp Biol. Mar; 218(Pt 6): 876-86. (2015).
*This article was featured in the column ‘Inside JEB’.
25. Farris DJ, Hicks J, Delp S, Sawicki GS, “Musculoskeletal modelling deconstructs the paradoxical effects of elastic ankle exoskeletons on plantar-flexor mechanics and energetics during hopping”. J Exp Biol. Nov 15; 217(Pt 22) 4018-28. (2014).
*24. Robertson BD, Farris DJ, Sawicki GS, “More is not always better: Modeling the effects of elastic exoskeleton compliance on underlying ankle muscle-tendon dynamics”. Bioinspir. Biomim. Nov 24; 9(4): 046018. (2014).
*Note: The free body diagram in the model schematic of Fig. 1 has a printing error. Fg should be Fgrf on the output side of the pulley – Fig 1. with corrected free body diagram
*23. Robertson BD, Sawicki GS, “Exploiting elasticity: Modeling the influence of neural control on mechanics and energetics of ankle muscle-tendons during human hopping“. J Theor Biol. Jul 21; 353: 121-32. Epub Mar 16. (2014).
*Note: Equations for Metabolic Rate in Table 2 have errors in the inequalities. Should be Vce<0 for first line and Vce>=0 for second line.
22. Shamaei K, Sawicki GS, Dollar A, “Estimation of quasi-stiffness of the human hip in the stance phase of walking”. PLoS One. 8(12): e81841. Epub Dec 9. (2013).
21. Matta P, Myers J, Sawicki GS, “The influence of available reaction time on ball-player impact probability in youth baseball”. Sports Health. Mar;7(2): 154-60. doi: 10.1177/1941738113498209. (2013).
20. Farris DJ, Robertson BD, Sawicki GS, “Passive elastic exoskeletons reduce soleus muscle force but not work in human hopping”. J Appl Physiol. Sep 1; 115(5): 579-85 Epub Jun 20. (2013).
19. Shamaei K, Sawicki GS, Dollar A,“Estimation of quasi-stiffness and propulsive work of the human ankle in the stance phase of walking“. PLoS One. 8(3): e59935. Epub Mar 21. (2013).
18. Shamaei K, Sawicki GS, Dollar A,“Estimation of quasi-stiffness of the human knee in the stance phase of walking“. PLoS One. 8(3): e59935. Epub Mar 22. (2013).
*17. Farris DJ, Sawicki GS, “Linking the mechanics and energetics of hopping with passive elastic ankle exoskeletons”. J Appl Physiol. Dec 15; 113(12): 1862-72. Epub Oct 11. (2012).
*Erratum in: J Appl Physiol. 2013 Jul 15;115(2):293 – Fig 6B. with corrected y-scale
16. Richards C, Sawicki GS, “Elastic recoil can either amplify or attenuate muscle-tendon power depending on inertial versus fluid dynamic loading”. J Theor Biol. Nov 21, 313:68-78. Epub Aug 8. (2012).
15. Wutzke CJ, Sawicki GS, Lewek MD, “The influence of a unilateral fixed ankle on metabolic and mechanical demands during walking in unimpaired young adults“. J Biomech. Sep 21, 45(14): 2405-10. Epub Jul 25. (2012).
*14. Farris DJ, Sawicki GS, “Human medial gastrocnemius force-velocity behavior shifts with locomotion speed and gait“. Proc Natl Acad of Sci USA. Jan 17, 109(3): 977-82. Epub Jan 4. (2012).
*Note: Units on velocity graphs from running in (Fig. 1F and Fig. S2E,F,G,H.) should be labeled mm/s, NOT m/s.
13. Farris DJ, Sawicki GS, “The mechanics and energetics of human walking and running: a joint-level perspective”. J R Soc Interface. Jan 7, 9(66): 110-8. Epub 2011 May 25. (2012).
12. Sawicki GS, Lewis CL, Ferris DP, “It pays to have a spring in your step”. Exerc Sport Sci Rev. 37(3):130-8 (2009).
11. Sawicki GS, Ferris DP, “A pneumatically powered knee-ankle-foot orthosis (KAFO) with myoelectric activation and inhibition”. J Neuroeng Rehabil. 6(1):23 (2009).
10. Sawicki GS, Ferris DP, “Mechanics and energetics of incline walking with robotic ankle exoskeletons”. J Exp Biol. 212(Pt 1):32-41 (2009).
9. Sawicki GS, Ferris DP, “Powered exoskeletons reveal the metabolic cost of plantar flexor mechanical work during walking with longer steps at constant step frequency”. J Exp Biol. 212(Pt 1):21-31 (2009).
*8. Sawicki GS, Ferris DP, “Mechanics and energetics of level walking with powered ankle exoskeletons”. J Exp Biol. 211(Pt 9):1402-1413 (2008).
*This article was featured in the column ‘Inside JEB’.
7. Ferris DP, Sawicki GS, Daley, MA, “A physiologist’s perspective on robotic exoskeletons for human locomotion”. International Journal of Humanoid Robotics. 4(3):507-528 (2007).
6. Domingo A, Sawicki GS, Ferris DP, “Kinematics and muscle activity of individuals with incomplete spinal cord injury during treadmill stepping with and without manual assistance”. J Neuroeng Rehabil. 4:32 (2007).
5. Sawicki GS, Domingo A, Ferris DP, “The effects of powered ankle-foot orthoses on joint kinematics and muscle activation during walking in individuals with incomplete spinal cord injury “. J Neuroeng Rehabil. 3:3 (2006).
4. Gordon KE, Sawicki GS, Ferris DP, “Mechanical performance of artificial pneumatic muscles to power an ankle-foot orthosis”. J Biomech. 39(10):1832-41 (2006).
3. Ferris DP , Gordon KE, Sawicki GS, Peethambaran A, “An improved powered ankle-foot orthosis using proportional myoelectric control”. Gait Posture. 23(4):425-8 (2006).
2. Ferris DP, Sawicki GS, Domingo A., “Powered lower limb orthoses for gait rehabilitation”. Top Spinal Cord Inj Rehabil. 11(2):34-49 (2005).
1a. Sawicki GS, Hubbard M, Stronge WJ, “Reply to Comment on “How to hit home runs: Optimum baseball swing parameters for maximum range trajectories”, by G. S. Sawicki, M. Hubbard, and W. J. Stronge [Am. J. Phys. 71(11):1152-62 (2003)]”. Am J Phys. 73(2):185-89 (2005).
1. Sawicki GS, Hubbard M, Stronge WJ, “How to hit homeruns: Optimum bat swing parameters for maximum range trajectories”. Am J Phys. 71(11):1152-62 (2003).
Engineering Conference Proceedings (Peer Reviewed)
6. Kumar V, Ha S, Sawicki GS, Liu CK “Learning a control policy for fall prevention on an assistive walking device”. International Conference on Robotics and Automation ICRA. (2020).
5. Cox SM, Rubenson J, Sawicki GS “A soft-exosuit enables multi-scale analysis of wearable robotics in a bipedal animal model”. IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), October 1-5: (2018).
4. Elliot G, Sawicki GS, Marecki A, Herr H, “The biomechanics and energetics of human running using an elastic knee exoskeleton”. Proceedings of the 13th Biannual International IEEE Conference on Rehabilitation Robotics, June 24-June 26: (2013).
3. Robertson BD, Sawicki GS, “Influence of parallel spring-loaded exoskeleton on ankle muscle-tendon dynamics during simulated human hopping”. Proceedings of the 33rd Annual International Conference of the IEEE Engineering in Medicine and Biology Society, September 1-4: (2011).
*2. Wiggin MB, Collins SH, Sawicki GS, “An exoskeleton using controlled energy storage and release to aid ankle propulsion”. Proceedings of the 12th Biannual International IEEE Conference on Rehabilitation Robotics, June 29-July 1: (2011).
*This article was highlighted in Nature: 503.S16-17 (14 Nov 2013) — ‘Technology: Mobility Machines’.
1. Sawicki GS, Gordon KE, Ferris DP, “Powered lower limb orthoses: Applications in Motor Adapatation and Rehabilitation”. Proceedings of the 9th Biannual International IEEE Conference on Rehabilitation Robotics, June 28-July 1: 206-11 (2005).