How fiber dynamics of plantarflexor and dorsiflexor muscles based on EMG-driven approach can explain the metabolic cost at different gait speeds

2022 ◽  
Author(s):  
Pauline Gerus ◽  
Elodie Piche ◽  
Olivier Guérin ◽  
Frederic Chorin ◽  
Raphaël Zory
Keyword(s):  
Metabolic Cost ◽  
Fiber Dynamics

scholarly journals Reduced Achilles Tendon Stiffness Disrupts Calf Muscle Neuromechanics in Elderly Gait

Gerontology ◽  
2021 ◽  
pp. 1-11
Author(s):  
Rebecca L. Krupenevich ◽  
Owen N. Beck ◽  
Gregory S. Sawicki ◽  
Jason R. Franz
Keyword(s):  
Older Adults ◽  
Achilles Tendon ◽  
Metabolic Cost ◽  
Calf Muscle ◽  
Metabolic Energy ◽  
Joint Work ◽  
Tendon Stiffness ◽  
Age Related ◽  
Ankle Muscle ◽  
Metabolic Energy Expenditure

Older adults walk slower and with a higher metabolic energy expenditure than younger adults. In this review, we explore the hypothesis that age-related declines in Achilles tendon stiffness increase the metabolic cost of walking due to less economical calf muscle contractions and increased proximal joint work. This viewpoint may motivate interventions to restore ankle muscle-tendon stiffness, improve walking mechanics, and reduce metabolic cost in older adults.

scholarly journals Reducing the metabolic energy of walking and running using an unpowered hip exoskeleton

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Tiancheng Zhou ◽  
Caihua Xiong ◽  
Juanjuan Zhang ◽  
Di Hu ◽  
Wenbin Chen ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Design Method ◽  
Metabolic Cost ◽  
Metabolic Energy ◽  
Spring Stiffness ◽  
Spatiotemporal Parameters ◽  
The Common ◽  
Hip Flexion ◽  
Optimal Stiffness ◽  
Insight Into

Abstract Background Walking and running are the most common means of locomotion in human daily life. People have made advances in developing separate exoskeletons to reduce the metabolic rate of walking or running. However, the combined requirements of overcoming the fundamental biomechanical differences between the two gaits and minimizing the metabolic penalty of the exoskeleton mass make it challenging to develop an exoskeleton that can reduce the metabolic energy during both gaits. Here we show that the metabolic energy of both walking and running can be reduced by regulating the metabolic energy of hip flexion during the common energy consumption period of the two gaits using an unpowered hip exoskeleton. Methods We analyzed the metabolic rates, muscle activities and spatiotemporal parameters of 9 healthy subjects (mean ± s.t.d; 24.9 ± 3.7 years, 66.9 ± 8.7 kg, 1.76 ± 0.05 m) walking on a treadmill at a speed of 1.5 m s−1 and running at a speed of 2.5 m s−1 with different spring stiffnesses. After obtaining the optimal spring stiffness, we recruited the participants to walk and run with the assistance from a spring with optimal stiffness at different speeds to demonstrate the generality of the proposed approach. Results We found that the common optimal exoskeleton spring stiffness for walking and running was 83 Nm Rad−1, corresponding to 7.2% ± 1.2% (mean ± s.e.m, paired t-test p < 0.01) and 6.8% ± 1.0% (p < 0.01) metabolic reductions compared to walking and running without exoskeleton. The metabolic energy within the tested speed range can be reduced with the assistance except for low-speed walking (1.0 m s−1). Participants showed different changes in muscle activities with the assistance of the proposed exoskeleton. Conclusions This paper first demonstrates that the metabolic cost of walking and running can be reduced using an unpowered hip exoskeleton to regulate the metabolic energy of hip flexion. The design method based on analyzing the common energy consumption characteristics between gaits may inspire future exoskeletons that assist multiple gaits. The results of different changes in muscle activities provide new insight into human response to the same assistive principle for different gaits (walking and running).

scholarly journals Brain pathology recapitulates physiology: A network meta-analysis

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Thomas J. Vanasse ◽  
Peter T. Fox ◽  
P. Mickle Fox ◽  
Franco Cauda ◽  
Tommaso Costa ◽  
...  
Keyword(s):  
Network Architecture ◽  
Spatial Scales ◽  
Meta Analysis ◽  
Metabolic Cost ◽  
Common Mechanism ◽  
Brain Disorders ◽  
Brain Pathology ◽  
Structural Network ◽  
Meta Analyses ◽  
Function Network

AbstractNetwork architecture is a brain-organizational motif present across spatial scales from cell assemblies to distributed systems. Structural pathology in some neurodegenerative disorders selectively afflicts a subset of functional networks, motivating the network degeneration hypothesis (NDH). Recent evidence suggests that structural pathology recapitulating physiology may be a general property of neuropsychiatric disorders. To test this possibility, we compared functional and structural network meta-analyses drawing upon the BrainMap database. The functional meta-analysis included results from >7,000 experiments of subjects performing >100 task paradigms; the structural meta-analysis included >2,000 experiments of patients with >40 brain disorders. Structure-function network concordance was high: 68% of networks matched (pFWE < 0.01), confirming the broader scope of NDH. This correspondence persisted across higher model orders. A positive linear association between disease and behavioral entropy (p = 0.0006;R2 = 0.53) suggests nodal stress as a common mechanism. Corroborating this interpretation with independent data, we show that metabolic ‘cost’ significantly differs along this transdiagnostic/multimodal gradient.

scholarly journals Inter-population differences in salinity tolerance of adult wild Sacramento splittail: osmoregulatory and metabolic responses to salinity

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Christine E Verhille ◽  
Theresa F Dabruzzi ◽  
Dennis E Cocherell ◽  
Brian Mahardja ◽  
Fred Feyrer ◽  
...  
Keyword(s):  
San Francisco ◽  
Salinity Tolerance ◽  
Plasma Osmolality ◽  
Metabolic Cost ◽  
Central Valley ◽  
Metabolic Responses ◽  
Metabolic Rates ◽  
Spawning Habitat ◽  
Osmoregulatory Capacity ◽  
Sacramento Splittail

Abstract The Sacramento splittail (Pogonichthys macrolepidotus) is composed of two genetically distinct populations endemic to the San Francisco Estuary (SFE). The allopatric upstream spawning habitat of the Central Valley (CV) population connects with the sympatric rearing grounds via relatively low salinity waters, whereas the San Pablo (SP) population must pass through the relatively high-salinity Upper SFE to reach its allopatric downstream spawning habitat. We hypothesize that if migration through SFE salinities to SP spawning grounds is more challenging for adult CV than SP splittail, then salinity tolerance, osmoregulatory capacity, and metabolic responses to salinity will differ between populations. Osmoregulatory disturbances, assessed by measuring plasma osmolality and ions, muscle moisture and Na+-K+-ATPase activity after 168 to 336 h at 11‰ salinity, showed evidence for a more robust osmoregulatory capacity in adult SP relative to CV splittail. While both resting and maximum metabolic rates were elevated in SP splittail in response to increased salinity, CV splittail metabolic rates were unaffected by salinity. Further, the calculated difference between resting and maximum metabolic values, aerobic scope, did not differ significantly between populations. Therefore, improved osmoregulation came at a metabolic cost for SP splittail but was not associated with negative impacts on scope for aerobic metabolism. These results suggest that SP splittail may be physiologically adjusted to allow for migration through higher-salinity waters. The trends in interpopulation variation in osmoregulatory and metabolic responses to salinity exposures support our hypothesis of greater salinity-related challenges to adult CV than SP splittail migration and are consistent with our previous findings for juvenile splittail populations, further supporting our recommendation of population-specific management.

scholarly journals Using a simple rope-pulley system that mechanically couples the arms, legs, and treadmill reduces the metabolic cost of walking

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Daisey Vega ◽  
Christopher J. Arellano
Keyword(s):  
Metabolic Cost ◽  
Metabolic Energy ◽  
Metabolic Effects ◽  
Whole Body ◽  
Walking Ability ◽  
Arm Swing ◽  
Pulley System ◽  
Young Subjects ◽  
Walking Recovery ◽  
Set Up

Abstract Background Emphasizing the active use of the arms and coordinating them with the stepping motion of the legs may promote walking recovery in patients with impaired lower limb function. Yet, most approaches use seated devices to allow coupled arm and leg movements. To provide an option during treadmill walking, we designed a rope-pulley system that physically links the arms and legs. This arm-leg pulley system was grounded to the floor and made of commercially available slotted square tubing, solid strut channels, and low-friction pulleys that allowed us to use a rope to connect the subject’s wrist to the ipsilateral foot. This set-up was based on our idea that during walking the arm could generate an assistive force during arm swing retraction and, therefore, aid in leg swing. Methods To test this idea, we compared the mechanical, muscular, and metabolic effects between normal walking and walking with the arm-leg pulley system. We measured rope and ground reaction forces, electromyographic signals of key arm and leg muscles, and rates of metabolic energy consumption while healthy, young subjects walked at 1.25 m/s on a dual-belt instrumented treadmill (n = 8). Results With our arm-leg pulley system, we found that an assistive force could be generated, reaching peak values of 7% body weight on average. Contrary to our expectation, the force mainly coincided with the propulsive phase of walking and not leg swing. Our findings suggest that subjects actively used their arms to harness the energy from the moving treadmill belt, which helped to propel the whole body via the arm-leg rope linkage. This effectively decreased the muscular and mechanical demands placed on the legs, reducing the propulsive impulse by 43% (p < 0.001), which led to a 17% net reduction in the metabolic power required for walking (p = 0.001). Conclusions These findings provide the biomechanical and energetic basis for how we might reimagine the use of the arms in gait rehabilitation, opening the opportunity to explore if such a method could help patients regain their walking ability. Trial registration: Study registered on 09/29/2018 in ClinicalTrials.gov (ID—NCT03689647).

scholarly journals Limitations of Foot-Worn Sensors for Assessing Running Power

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 4952
Author(s):  
Tobias Baumgartner ◽  
Steffen Held ◽  
Stefanie Klatt ◽  
Lars Donath
Keyword(s):  
Time Use ◽  
Stride Length ◽  
Metabolic Cost ◽  
Running Economy ◽  
Accelerometer Data ◽  
Gait Characteristics ◽  
Significant Difference ◽  
Metabolic Costs ◽  
Ground Contact Time ◽  
Training Signal

Running power as measured by foot-worn sensors is considered to be associated with the metabolic cost of running. In this study, we show that running economy needs to be taken into account when deriving metabolic cost from accelerometer data. We administered an experiment in which 32 experienced participants (age = 28 ± 7 years, weekly running distance = 51 ± 24 km) ran at a constant speed with modified spatiotemporal gait characteristics (stride length, ground contact time, use of arms). We recorded both their metabolic costs of transportation, as well as running power, as measured by a Stryd sensor. Purposely varying the running style impacts the running economy and leads to significant differences in the metabolic cost of running (p < 0.01). At the same time, the expected rise in running power does not follow this change, and there is a significant difference in the relation between metabolic cost and power (p < 0.001). These results stand in contrast to the previously reported link between metabolic and mechanical running characteristics estimated by foot-worn sensors. This casts doubt on the feasibility of measuring running power in the field, as well as using it as a training signal.

scholarly journals Mechanics, energetics and implementation of grounded running technique: a narrative review

2020 ◽  
Vol 6 (1) ◽  
pp. e000963
Author(s):  
Sheeba Davis ◽  
Aaron Fox ◽  
Jason Bonacci ◽  
Fiddy Davis
Keyword(s):  
Postural Stability ◽  
Injury Risk ◽  
Metabolic Cost ◽  
Duty Factor ◽  
Vertical Oscillation ◽  
Leg Stiffness ◽  
Speed Range ◽  
Impact Attenuation ◽  
Acute Increase ◽  
Recreational Runners

Grounded running predominantly differs from traditional aerial running by having alternating single and double stance with no flight phase. Approximately, 16% of runners in an open marathon and 33% of recreational runners in a 5 km running event adopted a grounded running technique. Grounded running typically occurs at a speed range of 2–3 m·s−1, is characterised by a larger duty factor, reduced vertical leg stiffness, lower vertical oscillation of the centre of mass (COM) and greater impact attenuation than aerial running. Grounded running typically induces an acute increase in metabolic cost, likely due to the larger duty factor. The increased duty factor may translate to a more stable locomotion. The reduced vertical oscillation of COM, attenuated impact shock, and potential for improved postural stability may make grounded running a preferred form of physical exercise in people new to running or with low loading capacities (eg, novice overweight/obese, elderly runners, rehabilitating athletes). Grounded running as a less impactful, but metabolically more challenging form, could benefit these runners to optimise their cardio-metabolic health, while at the same time minimise running-related injury risk. This review discusses the mechanical demands and energetics of grounded running along with recommendations and suggestions to implement this technique in practice.

scholarly journals ATM: Promoter of Metabolic “Cost” Reduction and “Savings” Usage during Hypoxia through mTORC1 Regulation

2010 ◽  
Vol 40 (4) ◽  
pp. 501-502 ◽  
Author(s):  
Sang Gyun Kim ◽  
Andrew Y. Choo ◽  
John Blenis
Keyword(s):  
Cost Reduction ◽  
Metabolic Cost

The metabolic cost of fever in Pekin ducks

2011 ◽  
Vol 36 (2) ◽  
pp. 116-120 ◽  
Author(s):  
Manette Marais ◽  
Shane K. Maloney ◽  
David A. Gray
Keyword(s):  
Metabolic Cost ◽  
Pekin Ducks
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