scholarly journals Evidence for energy savings from aerial running in the Svalbard rock ptarmigan ( Lagopus muta hyperborea )

2011 ◽  
Vol 278 (1718) ◽  
pp. 2654-2661 ◽  
Author(s):  
R. L. Nudds ◽  
L. P. Folkow ◽  
J. J. Lees ◽  
P. G. Tickle ◽  
K.-A. Stokkan ◽  
...  
Keyword(s):  
Energy Expenditure ◽  
Energy Savings ◽  
Metabolic Energy ◽  
Current Evidence ◽  
Cost Of Transport ◽  
Walking Gait ◽  
High Speeds ◽  
Lagopus Muta ◽  
Metabolic Energy Expenditure ◽  
First Time

Svalbard rock ptarmigans were walked and run upon a treadmill and their energy expenditure measured using respirometry. The ptarmigan used three different gaits: a walking gait at slow speeds (less than or equal to 0.75 m s −1 ), grounded running at intermediate speeds (0.75 m s −1 < U < 1.67 m s −1 ) and aerial running at high speeds (greater than or equal to 1.67 m s −1 ). Changes of gait were associated with reductions in the gross cost of transport (COT; J kg −1 m −1 ), providing the first evidence for energy savings with gait change in a small crouched-postured vertebrate. In addition, for the first time (excluding humans) a decrease in absolute metabolic energy expenditure (rate of O 2 consumption) in aerial running when compared with grounded running was identified. The COT versus U curve varies between species and the COT was cheaper during aerial running than grounded running, posing the question of why grounded running should be used at all. Existing explanations (e.g. stability during running over rocky terrain) amount to just so stories with no current evidence to support them. It may be that grounded running is just an artefact of treadmill studies. Research investigating the speeds used by animals in the field is sorely needed.

Study of Rest Time of Workers Using Biomechanical Analysis

2006 ◽  
Vol 22 (02) ◽  
pp. 66-71
Author(s):  
Yasuhisa Okumoto
Keyword(s):  
Energy Expenditure ◽  
Steel Structures ◽  
Metabolic Energy ◽  
Biomechanical Analysis ◽  
Human Model ◽  
Digital Human Model ◽  
Work Cycle ◽  
Rest Time ◽  
Metabolic Energy Expenditure ◽  
Digital Human

This report focuses on welding work for the assembly of large steel structures as an example of physical jobs. Task simulations using a digital human model, including metabolic energy expenditure analysis, have been carried out using the biomechanical approach for typical welding postures. Moreover, necessary rest time to recover from fatigue has been studied, and the optimal work cycle in a day was examined. As a result, it can be concluded that the flat position for welding, the most widely applied posture, requires the greatest energy expenditure, whereas the overhead position is requires the least. Furthermore, it is concluded that the rule of taking short breaks and often is preferable from the viewpoint of recovery from fatigue, especially for work where the consumption of energy is large. Finally, an optimal work cycle is proposed.

scholarly journals The Relationship Between Gait Symmetry and Metabolic Demand in Individuals With Unilateral Transfemoral Amputation: A Preliminary Study

2019 ◽  
Vol 184 (7-8) ◽  
pp. e281-e287
Author(s):  
Caitlin E Mahon ◽  
Benjamin J Darter ◽  
Christopher L Dearth ◽  
Brad D Hendershot
Keyword(s):  
Energy Expenditure ◽  
Case Series ◽  
Step Length ◽  
Metabolic Energy ◽  
Metabolic Power ◽  
Transfemoral Amputation ◽  
Preliminary Study ◽  
Spatial Asymmetries ◽  
Metabolic Energy Expenditure ◽  
The Relationship

Abstract Introduction Temporal-spatial symmetry allows for optimal metabolic economy in unimpaired human gait. The gait of individuals with unilateral transfemoral amputation is characterized by temporal-spatial asymmetries and greater metabolic energy expenditure. The objective of this study was to determine whether temporal-spatial asymmetries account for greater metabolic energy expenditure in individuals with unilateral transfemoral amputation. Materials and Methods The relationship between temporal-spatial gait asymmetry and metabolic economy (metabolic power normalized by walking speed) was retrospectively examined in eighteen individuals with transfemoral amputation walking at a self-selected velocity overground. Pearson’s product-moment correlations were used to assess the relationship between: (1) step time symmetry and metabolic economy and (2) step length symmetry and metabolic economy. The retrospective analysis of this data was approved by the Walter Reed National Military Medical Center Institutional Review Board and all individuals provided written consent. Additional insights on this relationship are presented through a case series describing the temporal-spatial and metabolic responses of two individuals with transfemoral amputation who completed a split-belt treadmill walking test. Results For the cohort of individuals, there was no significant relationship between metabolic economy and either step time asymmetry or step length asymmetry. However, the case series showed a positive relationship between step length asymmetry and metabolic power as participants adapted to split-belt treadmill walking. Conclusion There is mixed evidence for the relationship between temporal-spatial asymmetries and metabolic energy expenditure. This preliminary study may suggest optimal metabolic energy expenditure in individuals with transfemoral amputation occurs at an individualized level of symmetry and resultant deviations incur a metabolic penalty. The results of this study support the idea that addressing only temporal-spatial gait asymmetries in individuals with transfemoral amputation through rehabilitation may not improve metabolic economy. Nevertheless, future prospective research is necessary to confirm these results and implications for clinical practice.

scholarly journals Energetic consequences of using a prosthesis with adaptive ankle motion during slope walking in persons with a transtibial amputation

2013 ◽  
Vol 38 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Benjamin J Darter ◽  
Jason M Wilken
Keyword(s):  
Mechanical Properties ◽  
Energy Expenditure ◽  
Energy Cost ◽  
Metabolic Energy ◽  
Prosthetic Design ◽  
Transtibial Amputation ◽  
Ankle Motion ◽  
Technological Advances ◽  
Walking Difficulty ◽  
Metabolic Energy Expenditure

Background:Technological advances in prosthetic design include the use of microprocessors that adapt device performance based on user motion. The Proprio ankle unit prepositions the foot to adjust for walking on slopes and increases foot clearance during swing to minimize gait deviations.Study design:Comparative analysis.Objectives:To investigate the effect of a prosthesis with adaptive ankle motion on physiological gait performance during slope walking.Methods:Six persons with a unilateral transtibial amputation completed treadmill walking tests at three slopes (−5°, 0°, and 5°). The participants were tested wearing a customary device, active Proprio (Pon), and an identical inactivated Proprio (Poff).Results:Metabolic energy expenditure, energy cost for walking, and rating of walking difficulty were not statistically different between the Pon and Poff for all tested slopes. However, for slope descent, energy expenditure and energy cost for walking improved significantly by an average of 10%–14% for both the Pon and Poff compared to the customary limb. Rating of walking difficulty also showed an improvement with slope descent for both the Pon and Poff compared to the customary device. An improvement with slope ascent was found for Pon compared to the customary limb only.Conclusions:Adaptive ankle motion provided no meaningful physiological benefit during slope walking. The Proprio was, however, less demanding than the customary device for slope descent. Differences in the mechanical properties of the prosthetic feet likely contributed to the changes.Clinical relevanceWhile the adaptive ankle motion did not affect metabolic energy expenditure or energy cost for walking, the results suggest close attention should be paid to the mechanical properties of the foot component. Assessment of gait on nonlevel surfaces is recommended to better understand the implications of different prosthetic design features.

Aspects of seasonal energy expenditure in the beaver (Castor canadensis Kuhl) at the northern limit of its distribution

1969 ◽  
Vol 47 (4) ◽  
pp. 471-481 ◽  
Author(s):  
Michael Aleksiuk ◽  
Ian McTaggart Cowan
Keyword(s):  
Energy Expenditure ◽  
Food Supply ◽  
Castor Canadensis ◽  
Metabolic Energy ◽  
Free Access ◽  
Mackenzie Delta ◽  
Northern Limit ◽  
Winter Food ◽  
Northern Portion ◽  
Metabolic Energy Expenditure

The beaver (Castor canadensis Kuhl) is subjected to a seasonally fluctuating energy regime in the northern portion of its distribution. During the summer the animal has free access to an abundant food supply in the form of growing plant material, while the winter food supply is limited to a store of cached saplings. The summer and winter periods are 4 and 8 months long respectively.In the Mackenzie Delta. Northwest Territories, growth was found to be rapid in the summer and absent in the winter, A winter weight loss characterized immature animals. Fat was deposited in the autumn, maintained during the winter, and mobilized in the spring. Animals were lean during the summer. Thyroid gland weights were high in the summer and low in the winter. It was concluded from these data that metabolic energy expenditure is high during the summer and low during the winter. This annual pattern is an inherent property of northern beavers. The adaptive significance of the pattern. is believed to be that energy expenditure is attuned to environmental energy availability.

scholarly journals Human walking in the real world: Interactions between terrain type, gait parameters, and energy expenditure

2019 ◽  
Author(s):  
DB Kowalsky ◽  
JR Rebula ◽  
LV Ojeda ◽  
PG Adamczyk ◽  
AD Kuo
Keyword(s):  
Energy Expenditure ◽  
Real World ◽  
Metabolic Cost ◽  
Metabolic Energy ◽  
Least Squares Regression ◽  
The Real ◽  
Terrain Type ◽  
Gait Parameters ◽  
Surface Irregularities ◽  
Metabolic Energy Expenditure

AbstractHumans often traverse real-world environments with a variety of surface irregularities and inconsistencies, which can disrupt steady gait and require additional effort. Such effects have, however, scarcely been demonstrated quantitatively, because few laboratory biomechanical measures apply outdoors. Walking can nevertheless be quantified by other means. In particular, the foot’s trajectory in space can be reconstructed from foot-mounted inertial measurement units (IMUs), to yield measures of stride and associated variabilities. But it remains unknown whether such measures are related to metabolic energy expenditure. We therefore quantified the effect of five different outdoor terrains on foot motion (from IMUs) and net metabolic rate (from oxygen consumption) in healthy adults (N = 10; walking at 1.25 m/s). Energy expenditure increased significantly (P < 0.05) in the order Sidewalk, Dirt, Gravel, Grass, and Woodchips, with Woodchips about 27% costlier than Sidewalk. Terrain type also affected measures, particularly stride variability and virtual foot clearance (swing foot’s lowest height above consecutive footfalls). In combination, such measures can also roughly predict metabolic cost (adjusted R2 = 0.52, partial least squares regression), and even discriminate between terrain types (10% reclassification error). Body-worn sensors can characterize how uneven terrain affects gait, gait variability, and metabolic cost in the real world.

scholarly journals Relatively Shorter Muscle Lengths Increase the Metabolic Rate of Cyclic Force Production

2021 ◽  
Author(s):  
Owen N. Beck ◽  
Jordyn N. Schroeder ◽  
Lindsey H. Trejo. ◽  
Jason R. Franz ◽  
Gregory S. Sawicki
Keyword(s):  
Energy Expenditure ◽  
Plantar Flexion ◽  
Force Production ◽  
Biological Tissues ◽  
Metabolic Energy ◽  
Fascicle Length ◽  
Leg Muscles ◽  
Muscle Fascicle ◽  
Length Relationship ◽  
Metabolic Energy Expenditure

AbstractDuring animal locomotion, force-producing leg muscles are almost exclusively responsible for the whole-body’s metabolic energy expenditure. Animals can change the length of these leg muscles by altering body posture (e.g.,joint angles), kinetics (e.g.,body weight), or the structural properties of their biological tissues (e.g.,tendon stiffness). Currently, it is uncertain whether relative muscle fascicle operating length has a measurable effect on the metabolic energy expenditure of cyclic locomotion-like contractions. To address this uncertainty, we measured the metabolic energy expenditure of human participants as they cyclically produce two distinct ankle moments at three separate ankle angles (90°, 105°, 120°) on a fixed-position dynamometer exclusively using their soleus. Overall, increasing participant ankle angle from 90° to 120° (more plantar flexion) reduced minimum soleus fascicle length by 17% (both moment levels, p<0.001) and increased metabolic energy expenditure by an average of 208% (both p<0.001). Across both moment levels, the increased metabolic energy expenditure was not driven by greater fascicle positive mechanical work (higher moment level, p=0.591), fascicle force rate (both p≥0.235), or active muscle volume (both p≥0.122); but it was correlated with average relative soleus fascicle length (r=-179, p=0.002) and activation (r=0.51, p<0.001). Therefore, the metabolic energy expended during locomotion can likely be reduced by lengthening active muscles that operate on the ascending-limb of their force-length relationship.

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