scholarly journals Energetics of Walking With a Robotic Knee Exoskeleton

2019 ◽  
Vol 35 (5) ◽  
pp. 320-326 ◽  
Author(s):  
Mhairi K. MacLean ◽  
Daniel P. Ferris
Keyword(s):  
Healthy Subjects ◽  
Metabolic Cost ◽  
Treadmill Walking ◽  
Mechanical Work ◽  
Work Demand ◽  
Cost Of Locomotion ◽  
Outdoor Walking ◽  
Natural Terrain ◽  
Backpack Load ◽  
Loaded Walking

The authors tested 4 young healthy subjects walking with a powered knee exoskeleton to determine if it could reduce the metabolic cost of locomotion. Subjects walked with a backpack loaded and unloaded, on a treadmill with inclinations of 0° and 15°, and outdoors with varied natural terrain. Participants walked at a self-selected speed (average 1.0 m/s) for all conditions, except incline treadmill walking (average 0.5 m/s). The authors hypothesized that the knee exoskeleton would reduce the metabolic cost of walking uphill and with a load compared with walking without the exoskeleton. The knee exoskeleton reduced metabolic cost by 4.2% in the 15° incline with the backpack load. All other conditions had an increase in metabolic cost when using the knee exoskeleton compared with not using the exoskeleton. There was more variation in metabolic cost over the outdoor walking course with the knee exoskeleton than without it. Our findings indicate that powered assistance at the knee is more likely to decrease the metabolic cost of walking in uphill conditions and during loaded walking rather than in level conditions without a backpack load. Differences in positive mechanical work demand at the knee for varying conditions may explain the differences in metabolic benefit from the exoskeleton.

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

2011 ◽  
Vol 9 (66) ◽  
pp. 110-118 ◽  
Author(s):  
Dominic James Farris ◽  
Gregory S. Sawicki
Keyword(s):  
Power Output ◽  
Lower Limb ◽  
Metabolic Cost ◽  
Mechanical Work ◽  
Total Power ◽  
Joint Mechanics ◽  
Metabolic Power ◽  
Cost Of Transport ◽  
Cost Of Locomotion ◽  
Shed Light

Humans walk and run at a range of speeds. While steady locomotion at a given speed requires no net mechanical work, moving faster does demand both more positive and negative mechanical work per stride. Is this increased demand met by increasing power output at all lower limb joints or just some of them? Does running rely on different joints for power output than walking? How does this contribute to the metabolic cost of locomotion? This study examined the effects of walking and running speed on lower limb joint mechanics and metabolic cost of transport in humans. Kinematic and kinetic data for 10 participants were collected for a range of walking (0.75, 1.25, 1.75, 2.0 m s −1 ) and running (2.0, 2.25, 2.75, 3.25 m s −1 ) speeds. Net metabolic power was measured by indirect calorimetry. Within each gait, there was no difference in the proportion of power contributed by each joint (hip, knee, ankle) to total power across speeds. Changing from walking to running resulted in a significant ( p = 0.02) shift in power production from the hip to the ankle which may explain the higher efficiency of running at speeds above 2.0 m s −1 and shed light on a potential mechanism behind the walk–run transition.

scholarly journals Taking advantage of external mechanical work to reduce metabolic cost: the mechanics and energetics of split‐belt treadmill walking

2019 ◽  
Vol 597 (15) ◽  
pp. 4053-4068 ◽  
Author(s):  
Natalia Sánchez ◽  
Surabhi N. Simha ◽  
J. Maxwell Donelan ◽  
James M. Finley
Keyword(s):  
Metabolic Cost ◽  
Treadmill Walking ◽  
Mechanical Work

Metabolic cost of locomotion during treadmill walking with blood flow restriction

2013 ◽  
Vol 34 (4) ◽  
pp. 308-316 ◽  
Author(s):  
Goncalo V. Mendonca ◽  
João R. Vaz ◽  
Micael S. Teixeira ◽  
Telma Grácio ◽  
Pedro Pezarat-Correia
Keyword(s):  
Blood Flow ◽  
Metabolic Cost ◽  
Treadmill Walking ◽  
Blood Flow Restriction ◽  
Flow Restriction ◽  
Cost Of Locomotion

The Metabolic Cost of Locomotion; Muscle by Muscle

2011 ◽  
Vol 39 (2) ◽  
pp. 57-58 ◽  
Author(s):  
Rodger Kram ◽  
Christopher J. Arellano ◽  
Jason R. Franz
Keyword(s):  
Metabolic Cost ◽  
Cost Of Locomotion

scholarly journals The metabolic cost of turning right side up in the Mediterranean spur-thighed tortoise (Testudo graeca)

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Heather E. Ewart ◽  
Peter G. Tickle ◽  
William I. Sellers ◽  
Markus Lambertz ◽  
Dane A. Crossley ◽  
...  
Keyword(s):  
Video Analysis ◽  
Metabolic Cost ◽  
Physiological Process ◽  
Specific Power ◽  
Inverted Position ◽  
Testudo Graeca ◽  
Fitness Traits ◽  
Evolutionary Advantage ◽  
Cost Of Locomotion ◽  
In The Wild

AbstractArmoured, rigid bodied animals, such as Testudines, must self-right should they find themselves in an inverted position. The ability to self-right is an essential biomechanical and physiological process that influences survival and ultimately fitness. Traits that enhance righting ability may consequently offer an evolutionary advantage. However, the energetic requirements of self-righting are unknown. Using respirometry and kinematic video analysis, we examined the metabolic cost of self-righting in the terrestrial Mediterranean spur-thighed tortoise and compared this to the metabolic cost of locomotion at a moderate, easily sustainable speed. We found that self-righting is, relatively, metabolically expensive and costs around two times the mass-specific power required to walk. Rapid movements of the limbs and head facilitate successful righting however, combined with the constraints of breathing whilst upside down, contribute a significant metabolic cost. Consequently, in the wild, these animals should favour environments or behaviours where the risk of becoming inverted is reduced.

Efficiency of uphill locomotion in nocturnal and diurnal lizards

1996 ◽  
Vol 199 (3) ◽  
pp. 587-592 ◽  
Author(s):  
C Farley ◽  
M Emshwiller
Keyword(s):  
Body Mass ◽  
Low Cost ◽  
Minimum Cost ◽  
Mechanical Work ◽  
Energetic Cost ◽  
Cost Of Transport ◽  
Unit Distance ◽  
Cost Of Locomotion ◽  
Average Body Mass ◽  
Average Body

Nocturnal geckos can walk on level ground more economically than diurnal lizards. One hypothesis for why nocturnal geckos have a low cost of locomotion is that they can perform mechanical work during locomotion more efficiently than other lizards. To test this hypothesis, we compared the efficiency of the nocturnal gecko Coleonyx variegatus (average body mass 4.2 g) and the diurnal skink Eumeces skiltonianus (average body mass 4.8 g) when they performed vertical work during uphill locomotion. We measured the rate of oxygen consumption when each species walked on the level and up a 50 slope over a range of speeds. For Coleonyx variegatus, the energetic cost of traveling a unit distance (the minimum cost of transport, Cmin) increased from 1.5 to 2.7 ml O2 kg-1 m-1 between level and uphill locomotion. For Eumeces skiltonianus, Cmin increased from 2.5 to 4.7 ml O2 kg-1 m-1 between level and uphill locomotion. By taking the difference between Cmin for level and uphill locomotion, we found that the efficiency of performing vertical work during locomotion was 37 % for Coleonyx variegatus and 19 % for Eumeces skiltonianus. The similarity between the 1.9-fold difference in vertical efficiency and the 1.7-fold difference in the cost of transport on level ground is consistent with the hypothesis that nocturnal geckos have a lower cost of locomotion than other lizards because they can perform mechanical work during locomotion more efficiently.

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