Dataset Information

Human walking isn't all hard work: evidence of soft tissue contributions to energy dissipation and return.

ABSTRACT: The muscles and tendons of the lower extremity are generally considered the dominant producers of positive and negative work during gait. However, soft-tissue deformations not captured by joint rotations might also dissipate, store and even return substantial energy to the body. A key locomotion event is the collision of the leg with the ground, which deforms soft tissues appreciably in running. Significant deformation might also result from the impulsive ground collision in walking. In a study of normal human walking (N=10; 0.7-2.0 m s(-1) speeds), we show indirect evidence for both negative and positive work performed by soft tissue, consistent with a damped elastic collision and rebound. We used the difference between measured joint work and another quantity - the work performed on the body center of mass - to indicate possible work performed by soft tissue. At 1.25 m s(-1), we estimated that soft tissue performs approximately 7.5 J of negative work per collision. This constitutes approximately 60% of the total negative collision work and 31% of the total negative work per stride. The amount of soft tissue work during collision increases sharply with speed. Each collision is followed by 4 J of soft tissue rebound that is also not captured by joint work measures. Soft tissue deformation may save muscles the effort of actively dissipating energy, and soft tissue elastic rebound could save up to 14% of the total positive work per stride. Soft tissues not only cushion impacts but also appear to perform substantial work.

SUBMITTER: Zelik KE

PROVIDER: S-EPMC2992466 | biostudies-literature | 2010 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Human walking isn't all hard work: evidence of soft tissue contributions to energy dissipation and return.

Zelik Karl E KE Kuo Arthur D AD

The Journal of experimental biology 20101201 Pt 24

The muscles and tendons of the lower extremity are generally considered the dominant producers of positive and negative work during gait. However, soft-tissue deformations not captured by joint rotations might also dissipate, store and even return substantial energy to the body. A key locomotion event is the collision of the leg with the ground, which deforms soft tissues appreciably in running. Significant deformation might also result from the impulsive ground collision in walking. In a study ...[more]

PMID: 21113007

Similar Datasets

Project description:BACKGROUND:There are many studies that have investigated biomechanical differences among prosthetic feet, but not changes due to adaptation over time. There is a need for objective measures to quantify the process of adaptation for individuals with a transtibial amputation. Mechanical power and work profiles are a primary focus for modern energy-storage-and-return type prostheses, which strive to increase energy return from the prosthesis. The amount of energy a prosthesis stores and returns (i.e., negative and positive work) during stance is directly influenced by the user's loading strategy, which may be sensitive to alterations during the course of an adaptation period. The purpose of this study was to examine changes in lower limb mechanical work profiles during walking following a three-week adaptation to a new prosthesis. METHODS:A retrospective analysis was performed on 22 individuals with a unilateral transtibial amputation. Individuals were given a new prosthesis at their current mobility level (K3 or above) and wore it for three weeks. Kinematic and kinetic measures were recorded from overground walking at 0, 1.5, and 3 weeks into the adaptation period at a self-selected pace. Positive and negative work done by the prosthesis and sound ankle-foot were calculated using a unified deformable segment model and a six-degrees-of-freedom model for the knee and hip. RESULTS:Positive work from the prosthesis ankle-foot increased by 6.1% and sound ankle-foot by 5.7% after 3 weeks (p?=?0.041, 0.036). No significant changes were seen in negative work from prosthesis or sound ankle-foot (p?=?0.115, 0.192). There was also a 4.1% increase in self-selected walking speed after 3 weeks (p?=?0.038). Our data exhibited large inter-subject variations, in which some individuals followed group trends in work profiles while others had opposite trends in outcome variables. CONCLUSIONS:After a 3-week adaptation, 14 out of 22 individuals with a transtibial amputation increased energy return from the prosthesis. Such findings could indicate that individuals may better utilize the spring-like function of the prosthesis after an adaptation period.

Dataset Information

Human walking isn't all hard work: evidence of soft tissue contributions to energy dissipation and return.

Publications

Human walking isn't all hard work: evidence of soft tissue contributions to energy dissipation and return.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets