Gregory S Sawicki

Works (37)

2021 journal article

Isolating the energetic and mechanical consequences of imposed reductions in ankle and knee flexion during gait

JOURNAL OF NEUROENGINEERING AND REHABILITATION, 18(1).

By: E. McCain, T. Libera n, M. Berno, G. Sawicki, K. Saul & M. Lewek

author keywords: Biomechanics; Gait; Ankle; Knee; Metabolic cost
Source: Web Of Science
Added: March 15, 2021

2021 journal article

Neuromechanics and Energetics of Walking With an Ankle Exoskeleton Using Neuromuscular-Model Based Control: A Parameter Study

FRONTIERS IN BIOENGINEERING AND BIOTECHNOLOGY, 9.

By: B. Shafer*, S. Philius n, R. Nuckols*, J. McCall, A. Young* & G. Sawicki

author keywords: powered ankle exoskeleton; neuromuscular model; locomotion neuromechanics; human walking; muscle electromyography; metabolic energy cost; plantarflexor muscle-tendon mechanics
Source: Web Of Science
Added: May 10, 2021

2021 article

Reduced Achilles Tendon Stiffness Disrupts Calf Muscle Neuromechanics in Elderly Gait

Krupenevich, R. L., Beck, O. N., Sawicki, G. S., & Franz, J. R. (2021, July 16). GERONTOLOGY.

author keywords: Aging; Biomechanics; Stiffness; Energy expenditure; Muscle mechanics; Ankle exoskeleton
Source: Web Of Science
Added: August 2, 2021

2021 journal article

Reduced joint motion supersedes asymmetry in explaining increased metabolic demand during walking with mechanical restriction

JOURNAL OF BIOMECHANICS, 126.

By: E. McCain, M. Berno, T. Libera n, M. Lewek, G. Sawicki & K. Saul

author keywords: Gait; Asymmetry; Metabolic cost; Degrees of freedom; Joint restriction
Source: Web Of Science
Added: October 12, 2021

2020 journal article

Impact of elastic ankle exoskeleton stiffness on neuromechanics and energetics of human walking across multiple speeds

JOURNAL OF NEUROENGINEERING AND REHABILITATION, 17(1).

By: R. Nuckols n & G. Sawicki

author keywords: Locomotion; Wearable robotics; Plantarflexors; Spring-loaded; Lower-limb joints; Biomechanics; Metabolic cost; Compliant
Source: Web Of Science
Added: July 13, 2020

2020 journal article

Older Adults Overcome Reduced Triceps Surae Structural Stiffness to Preserve Ankle Joint Quasi-Stiffness During Walking

JOURNAL OF APPLIED BIOMECHANICS, 36(4), 209–216.

By: R. Krupenevich*, W. Clark*, G. Sawicki & J. Franz

author keywords: Achilles tendon; activation; aging; plantar flexor; biofeedback
Source: Web Of Science
Added: August 17, 2020

2019 journal article

Development of a Novel Gait Analysis Tool Measuring Center of Pressure for Evaluation of Canine Chronic Thoracolumbar Spinal Cord Injury

Journal of Neurotrauma, 36(21), 3018–3025.

By: M. Lewis, K. Williams, T. Langley*, L. Jarvis*, G. Sawicki & N. Olby

author keywords: center of pressure; chronic spinal cord injury; dogs; locomotion; postural control
Sources: Web Of Science, ORCID, Crossref
Added: June 24, 2019

2019 journal article

Mechanics and energetics of post-stroke walking aided by a powered ankle exoskeleton with speed-adaptive myoelectric control

JOURNAL OF NEUROENGINEERING AND REHABILITATION, 16.

By: E. McCain, T. Dick*, T. Giest n, R. Nuckols*, M. Lewek, K. Saul, G. Sawicki

author keywords: Ankle mechanics; Exoskeleton; Trailing limb angle; Propulsion; Myoelectric control; Electromyography; Metabolic cost; Hemiparesis; Stroke rehabilitation; Walking
Source: Web Of Science
Added: June 4, 2019

2017 journal article

A benchtop biorobotic platform for in vitro observation of muscle-tendon dynamics with parallel mechanical assistance from an elastic exoskeleton

JOURNAL OF BIOMECHANICS, 57, 8–17.

By: B. Robertson, S. Vadakkeveedu n & G. Sawicki

author keywords: Biomechanics; Elastic exoskeleton; Muscle-tendon mechanics; Unconstrained work loops; Biorobotics
Source: Web Of Science
Added: August 6, 2018

2017 article

An In Vitro Approach for Directly Observing Muscle-Tendon Dynamics with Parallel Elastic Mechanical Assistance

CONVERGING CLINICAL AND ENGINEERING RESEARCH ON NEUROREHABILITATION II, VOLS 1 AND 2, Vol. 15, pp. 643–647.

By: G. Sawicki & B. Robertson*

Source: Web Of Science
Added: August 6, 2018

2017 journal article

Quantifying center of pressure variability in chondrodystrophoid dogs

The Veterinary Journal, 226, 26–31.

By: S. Blau, L. Davis n, A. Gorney, C. Dohse, K. Williams, J. Lim, W. Pfitzner n, E. Laber, G. Sawicki, N. Olby

author keywords: Locomotion; Kinematics; Center of gravity
Sources: Web Of Science, Crossref, ORCID
Added: August 6, 2018

2017 journal article

The springs of time-limited bullfrog jumps and slow-preparation grasshopper leaps are tuned to their muscle dynamics

Integrative and Comparative Biology, 57, E390–390.

By: M. Rosario, G. Sutton, S. Patek & G. Sawicki

Source: NC State University Libraries
Added: August 6, 2018

2016 journal article

A Simple Model to Estimate Plantarflexor Muscle-Tendon Mechanics and Energetics During Walking With Elastic Ankle Exoskeletons

IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING, 63(5), 914–923.

By: G. Sawicki & N. Khan*

author keywords: Ankle exoskeleton; computer simulation; elastic energy storage; energetics; Hill-type muscle model; human walking; metabolic cost; muscle-tendon dynamics; plantarflexors (PF)
Source: Web Of Science
Added: August 6, 2018

2016 journal article

A cyber expert system for auto-tuning powered prosthesis impedance control parameters

Annals of Biomedical Engineering, 44(5), 1613–1624.

By: H. Huang, D. Crouch, M. Liu, G. Sawicki & D. Wang n

Sources: NC State University Libraries, ORCID
Added: August 6, 2018

2016 journal article

Adding Stiffness to the Foot Modulates Soleus Force-Velocity Behaviour during Human Walking

SCIENTIFIC REPORTS, 6.

By: K. Takahashi*, M. Gross*, H. Werkhoven*, S. Piazza* & G. Sawicki

Source: Web Of Science
Added: August 6, 2018

2016 journal article

Modeling age-related changes in muscle-tendon dynamics during cyclical contractions in the rat gastrocnemius

JOURNAL OF APPLIED PHYSIOLOGY, 121(4), 1004–1012.

By: N. Danos*, N. Holt*, G. Sawicki & E. Azizi*

author keywords: aging; elastic energy; cost of locomotion; fibrosis; ankle joint work
Source: Web Of Science
Added: August 6, 2018

2016 journal article

Muscle-spring dynamics in time-limited, elastic movements

By: M. Rosario*, G. Sutton*, S. Patek* & G. Sawicki

author keywords: muscle-spring interaction; elastic energy storage; muscle dynamics; time-limited loading; fixed-end contraction; spring stiffness
Source: Web Of Science
Added: August 6, 2018

2015 journal article

A neuromechanics-based powered ankle exoskeleton to assist walking post-stroke: a feasibility study

JOURNAL OF NEUROENGINEERING AND REHABILITATION, 12.

By: K. Takahashi, M. Lewek* & G. Sawicki

author keywords: Stroke; Exoskeleton; Gait; Rehabilitation; Ankle
Source: Web Of Science
Added: August 6, 2018

2015 journal article

Individual limb mechanical analysis of gait following stroke

JOURNAL OF BIOMECHANICS, 48(6), 984–989.

By: C. Mahon*, D. Farris, G. Sawicki & M. Lewek*

author keywords: Stroke; Hemiplegia; Rehabilitation; Gait; Mechanics
Source: Web Of Science
Added: August 6, 2018

2015 article

More is not always better: Modeling the effects of elastic exoskeleton compliance on underlying ankle muscle-tendon dynamics (vol 9, 046018, 2014)

Bioinspiration & Biomimetics, Vol. 10.

By: B. Robertson, D. Farris & G. Sawicki

Source: NC State University Libraries
Added: August 6, 2018

2015 journal article

Power amplification in an isolated muscle-tendon unit is load dependent

JOURNAL OF EXPERIMENTAL BIOLOGY, 218(22), 3700–3709.

By: G. Sawicki, P. Sheppard* & T. Roberts*

author keywords: Muscle-tendon system; Elastic energy; Power amplification; Catch mechanism; Acceleration; Jumping
Source: Web Of Science
Added: August 6, 2018

2015 journal article

Reducing the energy cost of human walking using an unpowered exoskeleton

NATURE, 522(7555), 212-+.

By: S. Collins*, M. Wiggin n & G. Sawicki

Source: Web Of Science
Added: August 6, 2018

2015 journal article

Revisiting the mechanics and energetics of walking in individuals with chronic hemiparesis following stroke: from individual limbs to lower limb joints

JOURNAL OF NEUROENGINEERING AND REHABILITATION, 12.

By: D. Farris, A. Hampton n, M. Lewek* & G. Sawicki

author keywords: Locomotion; Individual limbs method; Mechanical power; Metabolic power; Joint power; Inverse dynamics; Stroke
Source: Web Of Science
Added: August 6, 2018

2015 journal article

Six degree-of-freedom analysis of hip, knee, ankle and foot provides updated understanding of biomechanical work during human walking

JOURNAL OF EXPERIMENTAL BIOLOGY, 218(6), 876–886.

By: K. Zelik*, K. Takahashi & G. Sawicki

author keywords: Biomechanics; Foot work; Gait analysis; Inverse dynamics; Joint work; Mechanical work
Source: Web Of Science
Added: August 6, 2018

2015 journal article

Timing matters: tuning the mechanics of a muscle-tendon unit by adjusting stimulation phase during cyclic contractions

JOURNAL OF EXPERIMENTAL BIOLOGY, 218(19), 3150–3159.

author keywords: Muscle-tendon interaction; Muscle stimulation phase; Work loop; Elastic energy storage and return; Terrestrial locomotion
Source: Web Of Science
Added: August 6, 2018

2014 journal article

Exploiting elasticity: Modeling the influence of neural control on mechanics and energetics of ankle muscle-tendons during human hopping

JOURNAL OF THEORETICAL BIOLOGY, 353, 121–132.

By: B. Robertson & G. Sawicki

author keywords: Plantarflexors; Locomotion; Muscle mechanics; Metabolic cost; Elastic mechanisms
Source: Web Of Science
Added: August 6, 2018

2014 journal article

More is not always better: modeling the effects of elastic exoskeleton compliance on underlying ankle muscle-tendon dynamics

BIOINSPIRATION & BIOMIMETICS, 9(4).

By: B. Robertson, D. Farris & G. Sawicki

author keywords: elastic ankle exoskeleton; muscle-tendon interaction; mechanics; energetics; hopping; ultrasound
Source: Web Of Science
Added: August 6, 2018

2014 journal article

Musculoskeletal modelling deconstructs the paradoxical effects of elastic ankle exoskeletons on plantar-flexor mechanics and energetics during hopping

JOURNAL OF EXPERIMENTAL BIOLOGY, 217(22), 4018–4028.

By: D. Farris, J. Hicks*, S. Delp* & G. Sawicki

author keywords: Assistive robotics; Dynamics simulation; Energetics; Locomotion; Metabolic energy; Muscle mechanics
Source: Web Of Science
Added: August 6, 2018

2013 journal article

Elastic ankle exoskeletons reduce soleus muscle force but not work in human hopping

JOURNAL OF APPLIED PHYSIOLOGY, 115(5), 579–585.

By: D. Farris, B. Robertson & G. Sawicki

author keywords: ultrasound; fascicle; tendon; metabolic power; plantar flexors
Source: Web Of Science
Added: August 6, 2018

2013 journal article

Estimation of Quasi-Stiffness and Propulsive Work of the Human Ankle in the Stance Phase of Walking

PLOS ONE, 8(3).

By: K. Shamaei*, G. Sawicki & A. Dollar*

Source: Web Of Science
Added: August 6, 2018

2013 journal article

Estimation of Quasi-Stiffness of the Human Hip in the Stance Phase of Walking

PLOS ONE, 8(12).

By: K. Shamaei*, G. Sawicki & A. Dollar*

Source: Web Of Science
Added: August 6, 2018

2013 journal article

Estimation of Quasi-Stiffness of the Human Knee in the Stance Phase of Walking

PLOS ONE, 8(3).

By: K. Shamaei, G. Sawicki & A. Dollar

Source: Web Of Science
Added: August 6, 2018

2012 journal article

Elastic recoil can either amplify or attenuate muscle-tendon power, depending on inertial vs. fluid dynamic loading

JOURNAL OF THEORETICAL BIOLOGY, 313, 68–78.

By: C. Richards* & G. Sawicki

author keywords: Muscle power amplification; Gearing; Mechanical advantage; Mathematical model; Inertial and viscous loads
Source: Web Of Science
Added: August 6, 2018

2012 journal article

Human medial gastrocnemius force-velocity behavior shifts with locomotion speed and gait

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 109(3), 977–982.

By: D. Farris* & G. Sawicki

author keywords: muscle mechanics; biomechanics; preferred transition speed
Source: Web Of Science
Added: August 6, 2018

2012 journal article

The influence of a unilateral fixed ankle on metabolic and mechanical demands during walking in unimpaired young adults

JOURNAL OF BIOMECHANICS, 45(14), 2405–2410.

By: C. Wutzke*, G. Sawicki & M. Lewek*

author keywords: Gait; Biomechanics; Metabolic cost; Ankle
Source: Web Of Science
Added: August 6, 2018

2012 journal article

The mechanics and energetics of human walking and running: a joint level perspective

JOURNAL OF THE ROYAL SOCIETY INTERFACE, 9(66), 110–118.

By: D. Farris & G. Sawicki

author keywords: locomotion; speed; mechanical power; efficiency; cost of transport
Source: Web Of Science
Added: August 6, 2018

2011 conference paper

Influence of parallel spring-loaded exoskeleton on ankle muscle-tendon dynamics during simulated human hopping

2011 Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 583–586.

By: B. Robertson & G. Sawicki

Source: NC State University Libraries
Added: August 6, 2018