Soft tissue vibration: a biologically-inspired mechanism for stabilizing bipedal locomotion

Masters, Samuel E.; Challis, John H.

doi:10.1088/1748-3190/abd624

Cited by 3 publications

(2 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Other soft tissues such as ligaments can produce passive torques at the joints, but we would not expect these torques contribute significantly to our outcome measures throughout the joint ranges of motion that occur during walking. Soft tissue in human bodies can also oscillate during walking, functioning to store and dissipate energy [ 48 ]. However, at these walking speeds we would not expect soft tissue oscillation to be a major contributor to any of our primary outcome measures and thus it would add unnecessary complexity to the model.…”

Section: Discussionmentioning

confidence: 99%

Muscle contributions to pre-swing biomechanical tasks influence swing leg mechanics in individuals post-stroke during walking

Brough

Kautz

Neptune

2022

J NeuroEngineering Rehabil

View full text Add to dashboard Cite

Background Successful walking requires the execution of the pre-swing biomechanical tasks of body propulsion and leg swing initiation, which are often impaired post-stroke. While excess rectus femoris activity during swing is often associated with low knee flexion, previous work has suggested that deficits in propulsion and leg swing initiation may also contribute. The purpose of this study was to determine underlying causes of propulsion, leg swing initiation and knee flexion deficits in pre-swing and their link to stiff knee gait in individuals post-stroke. Methods Musculoskeletal models and forward dynamic simulations were developed for individuals post-stroke (n = 15) and healthy participants (n = 5). Linear regressions were used to evaluate the relationships between peak knee flexion, braking and propulsion symmetry, and individual muscle contributions to braking, propulsion, knee flexion in pre-swing, and leg swing initiation. Results Four out of fifteen of individuals post-stroke had higher plantarflexor contributions to propulsion and seven out of fifteen had higher vasti contributions to braking on their paretic leg relative to their nonparetic leg. Higher gastrocnemius contributions to propulsion predicted paretic propulsion symmetry (p = 0.005) while soleus contributions did not. Higher vasti contributions to braking in pre-swing predicted lower knee flexion (p = 0.022). The rectus femoris had minimal contributions to lower knee flexion acceleration in pre-swing compared to contributions from the vasti. However, for some individuals with low knee flexion, during pre-swing the rectus femoris absorbed more power and the iliopsoas contributed less power to the paretic leg. Total musculotendon work done on the paretic leg in pre-swing did not predict knee flexion during swing. Conclusions These results emphasize the multiple causes of propulsion asymmetry in individuals post-stroke, including low plantarflexor contributions to propulsion, increased vasti contributions to braking and reliance on compensatory mechanisms. The results also show that the rectus femoris is not a major contributor to knee flexion in pre-swing, but absorbs more power from the paretic leg in pre-swing in some individuals with stiff knee gait. These results highlight the need to identify individual causes of propulsion and knee flexion deficits to design more effective rehabilitation strategies.

show abstract

Section: Discussionmentioning

confidence: 99%

Muscle contributions to pre-swing biomechanical tasks influence swing leg mechanics in individuals post-stroke during walking

Brough

Kautz

Neptune

2022

J NeuroEngineering Rehabil

View full text Add to dashboard Cite

show abstract

“…For example, humans prefer a jump landing that requires 37% more muscletendon dissipation than minimally necessary (Zelik & Kuo, 2012). The amount of soft tissue dissipation may also have other effects such as on the stability of walking (Masters & Challis, 2020). The distribution between active and passive dissipation may therefore be relevant to metabolic cost and a variety of additional mechanical effects.…”

Section: Discussionmentioning

confidence: 99%

Soft tissue deformations explain most of the mechanical work variations of human walking

Zee

Kuo²

2021

Preprint

View full text Add to dashboard Cite

Humans perform mechanical work during walking, some by leg joints actuated by muscles, and some by passive, dissipative soft tissues. Dissipative losses must be restored by active muscle work, potentially in amounts sufficient to cost substantial metabolic energy. The most dissipative, and therefore costly, walking conditions might be predictable from the pendulum-like dynamics of the legs. If pendulum behavior is systematic, it may also predict the work distribution between active joints and passive soft tissues. We therefore tested whether the overall negative work of walking, and the fraction due to soft tissue dissipation, are both predictable by a pendulum model across a wide range of conditions. The model predicts whole-body negative work from the leading leg's impact with ground (termed the Collision), to increase with the squared product of walking speed and step length. We experimentally tested this in humans (N = 9) walking in 26 different combinations of speed (0.7 - 2.0 m/s) and step length (0.5 - 1.1 m), with recorded motions and ground reaction forces. Whole-body negative Collision work increased as predicted (R2 = 0.73), with a consistent fraction of about 63% (R2 = 0.88) due to soft tissues. Soft tissue dissipation consistently accounted for about 56% of the variation in total whole-body negative work. During typical walking, active work to restore dissipative losses could account for 31% of the net metabolic cost. Soft tissue dissipation, not included in most biomechanical studies, explains most of the variation in negative work of walking, and could account for a substantial fraction of the metabolic cost.

show abstract

Soft tissue deformations explain most of the mechanical work variations of human walking

Zee

Kuo

2021

Journal of Experimental Biology

View full text Add to dashboard Cite

Humans perform mechanical work during walking, some by leg joints actuated by muscles, and some by passive, dissipative soft tissues. Dissipative losses must be restored by active muscle work, potentially in amounts sufficient to cost substantial metabolic energy. The most dissipative, and therefore costly, walking conditions might be predictable from the pendulum-like dynamics of the legs. If this behavior is systematic, it may also predict the work distribution between active joints and passive soft tissues. We therefore tested whether the overall negative work of walking, and the fraction due to soft tissue dissipation, are both predictable by a simple dynamic walking model across a wide range of conditions. The model predicts whole-body negative work from the leading leg's impact with ground (termed the Collision), to increase with the squared product of walking speed and step length. We experimentally tested this in humans (N=9) walking in 26 different combinations of speed (0.7 – 2.0 m·s−1) and step length (0.5 – 1.1 m), with recorded motions and ground reaction forces. Whole-body negative Collision work increased as predicted (R2=0.73), with a consistent fraction of about 63% (R2=0.88) due to soft tissues. Soft tissue dissipation consistently accounted for about 56% of the variation in total whole-body negative work, across a wide range of speed and step length combinations. During typical walking, active work to restore dissipative losses could account for 31% of the net metabolic cost. Soft tissue dissipation, not included in most biomechanical studies, explains most of the variation in negative work of walking, and could account for a substantial fraction of the metabolic cost.

show abstract

Soft tissue vibration: a biologically-inspired mechanism for stabilizing bipedal locomotion

Cited by 3 publications

References 38 publications

Muscle contributions to pre-swing biomechanical tasks influence swing leg mechanics in individuals post-stroke during walking

Muscle contributions to pre-swing biomechanical tasks influence swing leg mechanics in individuals post-stroke during walking

Soft tissue deformations explain most of the mechanical work variations of human walking

Soft tissue deformations explain most of the mechanical work variations of human walking

Contact Info

Product

Resources

About