Individual Leg Muscle Contributions to the Cost of Walking: Effects of Age and Walking Speed

2017 ◽  
Vol 25 (2) ◽  
pp. 295-304 ◽  
Author(s):  
Patricio A. Pincheira ◽  
Lauri Stenroth ◽  
Janne Avela ◽  
Neil J. Cronin
Keyword(s):  
Energy Cost ◽  
Young Group ◽  
Energetic Cost ◽  
Elderly Subjects ◽  
Older Individuals ◽  
Cost Of Transport ◽  
Leg Muscles ◽  
Lower Limb Muscles ◽  
Walking Speeds ◽  
The Cost

This study examined the contributions of individual muscles to changes in energetic cost of transport (COT) over seven walking speeds, and compared results between healthy young and elderly subjects. Twenty six participants (13 young aged 18–30; 13 old aged 70–80) were recruited. COT (O2/kg body mass/km) was calculated by standardizing the mean oxygen consumption recorded during steady state walking. Electromyography signals from 10 leg muscles were used to calculate the cumulative activity required to traverse a unit of distance (CMAPD) for each muscle at each speed. In the old group CMAPD was correlated with COT, presented higher and more variable values, and showed greater increases around optimal speed for all studied muscles. Soleus CMAPD was independent of speed in the young group, but this was not evident with aging. Greater energy cost of walking in older individuals seems to be attributable to increased energy cost of all lower limb muscles.

scholarly journals Lower energy cost of skeletal muscle contractions in older humans

2010 ◽  
Vol 298 (3) ◽  
pp. R729-R739 ◽  
Author(s):  
Michael A. Tevald ◽  
Stephen A. Foulis ◽  
Ian R. Lanza ◽  
Jane A. Kent-Braun
Keyword(s):  
Energy Cost ◽  
Energetic Cost ◽  
Resonance Spectroscopy ◽  
Age Difference ◽  
Force Frequency ◽  
Older Individuals ◽  
Age Related ◽  
Frequency Relationship ◽  
The Cost

Recent studies suggest that the cost of muscle contraction may be reduced in old age, which could be an important mediator of age-related differences in muscle fatigue under some circumstances. We used phosphorus magnetic resonance spectroscopy and electrically elicited contractions to examine the energetic cost of ankle dorsiflexion in 9 young (Y; 26 ± 3.8 yr; mean ± SD) and 9 older healthy men (O; 72 ± 4.6). We hypothesized that the energy cost of twitch and tetanic contractions would be lower in O and that this difference would be greater during tetanic contractions at f50 (frequency at 50% of peak force from force-frequency relationship) than at 25 Hz. The energy costs of a twitch (O = 0.13 ± 0.04 mM ATP/twitch, Y = 0.18 ± 0.06; P = 0.045) and a 60-s tetanus at 25 Hz (O = 1.5 ± 0.4 mM ATP/s, Y = 2.0 ± 0.2; P = 0.01) were 27% and 26% lower in O, respectively, while the respective force·time integrals were not different. In contrast, energy cost during a 90-s tetanus at f50 (O = 10.9 ± 2.0 Hz, Y = 14.8 ± 2.1 Hz; P = 0.002) was 49% lower in O (1.0 ± 0.2 mM ATP/s) compared with Y (1.9 ± 0.2; P < 0.001). Y had greater force potentiation during the f50 protocol, which accounted for the greater age difference in energy cost at f50 compared with 25 Hz. These results provide novel evidence of an age-related difference in human contractile energy cost in vivo and suggest that intramuscular changes contribute to the lower cost of contraction in older muscle. This difference in energetics may provide an important mechanism for the enhanced fatigue resistance often observed in older individuals.

Speed, stride frequency and energy cost per stride: how do they change with body size and gait?

1988 ◽  
Vol 138 (1) ◽  
pp. 301-318 ◽  
Author(s):  
N. C. Heglund ◽  
C. R. Taylor
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Energy Cost ◽  
Reaction Force ◽  
Stride Frequency ◽  
Energetic Cost ◽  
Published Data ◽  
Frequency Change ◽  
Cost Of Locomotion ◽  
The Cost

In this study we investigate how speed and stride frequency change with body size. We use this information to define ‘equivalent speeds’ for animals of different size and to explore the factors underlying the six-fold difference in mass-specific energy cost of locomotion between mouse- and horse-sized animals at these speeds. Speeds and stride frequencies within a trot and a gallop were measured on a treadmill in 16 species of wild and domestic quadrupeds, ranging in body size from 30 g mice to 200 kg horses. We found that the minimum, preferred and maximum sustained speeds within a trot and a gallop all change in the same rather dramatic manner with body size, differing by nine-fold between mice and horses (i.e. all three speeds scale with about the 0.2 power of body mass). Although the absolute speeds differ greatly, the maximum sustainable speed was about 2.6-fold greater than the minimum within a trot, and 2.1-fold greater within a gallop. The frequencies used to sustain the equivalent speeds (with the exception of the minimum trotting speed) scale with about the same factor, the −0.15 power of body mass. Combining this speed and frequency data with previously published data on the energetic cost of locomotion, we find that the mass-specific energetic cost of locomotion is almost directly proportional to the stride frequency used to sustain a constant speed at all the equivalent speeds within a trot and a gallop, except for the minimum trotting speed (where it changes by a factor of two over the size range of animals studied). Thus the energy cost per kilogram per stride at five of the six equivalent speeds is about the same for all animals, independent of body size, but increases with speed: 5.0 J kg-1 stride-1 at the preferred trotting speed; 5.3 J kg-1 stride-1 at the trot-gallop transition speed; 7.5 J kg-1 stride-1 at the preferred galloping speed; and 9.4 J kg-1 stride-1 at the maximum sustained galloping speed. The cost of locomotion is determined primarily by the cost of activating muscles and of generating a unit of force for a unit of time. Our data show that both these costs increase directly with the stride frequency used at equivalent speeds by different-sized animals. The increase in cost per stride with muscles (necessitating higher muscle forces for the same ground reaction force) as stride length increases both in the trot and in the gallop.

Dynamics of photoconversion processes: the energetic cost of lifetime gain in photosynthetic and photovoltaic systems

2021 ◽  
Author(s):  
Robert Godin ◽  
James R. Durrant
Keyword(s):  
Kinetic Model ◽  
Solar Energy ◽  
Energy Conversion ◽  
Energy Cost ◽  
Energetic Cost ◽  
Photovoltaic Systems ◽  
Simple Kinetic Model ◽  
Energy Conversion Systems ◽  
Order Of Magnitude ◽  
The Cost

The energy cost of lifetime gain in solar energy conversion systems is determined from a breadth of technologies. The cost of 87 meV per order of magnitude lifetime improvement is strikingly close to the 59 meV determined from a simple kinetic model.

scholarly journals The rising cost of warming waters: effects of temperature on the cost of swimming in fishes

2011 ◽  
Vol 8 (2) ◽  
pp. 266-269 ◽  
Author(s):  
Andrew M. Hein ◽  
Katrina J. Keirsted
Keyword(s):  
Water Temperature ◽  
Fish Species ◽  
Global Climate ◽  
Swimming Performance ◽  
Metabolic Cost ◽  
Quantitative Model ◽  
The Body ◽  
Energetic Cost ◽  
Cost Of Transport ◽  
The Cost

Understanding the effects of water temperature on the swimming performance of fishes is central in understanding how fish species will respond to global climate change. Metabolic cost of transport (COT)—a measure of the energy required to swim a given distance—is a key performance parameter linked to many aspects of fish life history. We develop a quantitative model to predict the effect of water temperature on COT. The model facilitates comparisons among species that differ in body size by incorporating the body mass-dependence of COT. Data from 22 fish species support the temperature and mass dependencies of COT predicted by our model, and demonstrate that modest differences in water temperature can result in substantial differences in the energetic cost of swimming.

Walking Speed at Self-Selected Exercise Pace Is Lower but Energy Cost Higher in Older Versus Younger Women

2009 ◽  
Vol 6 (3) ◽  
pp. 327-332 ◽  
Author(s):  
Lynnette M. Jones ◽  
Debra L. Waters ◽  
Michael Legge
Keyword(s):  
Older Women ◽  
Energy Cost ◽  
Walking Speed ◽  
Metabolic Cost ◽  
Energetic Cost ◽  
Energy Costs ◽  
Energy Equivalent ◽  
Younger Women ◽  
Exercise Modality ◽  
Walking Speeds

Background:Walking is usually undertaken at a speed that coincides with the lowest metabolic cost. Aging however, alters the speed–cost relationship, as preferred walking speeds decrease and energy costs increase. It is unclear to what extent this relationship is affected when older women undertake walking as an exercise modality. The aim of this study was to compare the energetic cost of walking at a self-selected exercise pace for 30 min in older and younger women.Methods:The energetic cost of walking was assessed using the energy equivalent of oxygen consumption measured in 18 young (25 to 49 y) and 20 older (50 to 79 y) women who were asked to walk at their “normal” exercise pace on a motorized treadmill for 30 min.Results:The mass-specific net cost of walking (Cw) was 15% higher and self-selected walking speed was 23% lower in the older women than in the younger group. When speed was held constant, the Cw was 0.30 (J · .kg−1 · m−1) higher in the older women.Conclusions:Preferred exercise pace incurs a higher metabolic cost in older women and needs be taken into consideration when recommending walking as an exercise modality.

Energy-optimal relative timing of stance-leg push-off and swing-leg retraction in walking

Robotica ◽  
2015 ◽  
Vol 35 (3) ◽  
pp. 654-686 ◽  
Author(s):  
S. Javad Hasaneini ◽  
John E. A. Bertram ◽  
Chris J. B. Macnab
Keyword(s):  
Force Production ◽  
Energetic Cost ◽  
High Fidelity ◽  
Ground Contact ◽  
Relative Timing ◽  
Mechanical Coupling ◽  
Leg Extension ◽  
Walking Speeds ◽  
The Cost ◽  
Aperiodic Gaits

SUMMARYSwing-leg retraction in walking is the slowing or reversal of the forward rotation of the swing leg at the end of the swing phase prior to ground contact. For retraction, a hip torque is often applied to the swing leg at about the same time as stance-leg push-off. Due to mechanical coupling, the push-off force affects leg swing, and hip torque affects the stance-leg extension. This coupling makes the energetic costs of retraction and push-off depend on their relative timing. Here, we find the energy-optimal relative timing of these actions. We first use a simplified walking model with non-regenerative actuators, a work-based energetic-cost, and impulsive actuations. Depending on whether the late-swing hip torque is retracting or extending (pushing the leg forward), we find that the optimum is obtained by applying the impulsive hip torque either following or prior to the impulsive push-off force, respectively. These trends extend to other bipedal models and to aperiodic gaits, and are independent of step lengths and walking speeds. In one simulation, the cost of a walking step is increased by 17.6% if retraction torque comes before push-off. To consider non-impulsive actuation and the cost of force production, we add a force-squared (F2) term to the work cost. We show that this cost promotes simultaneous push-off force and retracting torque, but does not change the result that any extending torque should come prior to push-off. A high-fidelity optimization of the Cornell Ranger robot is consistent with the swing-retraction trends from the models above.

The Cost of Gait Slowness: Can Persons with Parkinson’s Disease Save Energy by Walking Faster?

2021 ◽  
Vol 11 (4) ◽  
pp. 2073-2084
Author(s):  
Purnima Padmanabhan ◽  
Keerthana Sreekanth Rao ◽  
Anthony J. Gonzalez ◽  
Alexander Y. Pantelyat ◽  
Vikram S. Chib ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Energy Cost ◽  
Walking Speed ◽  
Patient Specific ◽  
Dopaminergic Medication ◽  
Gait Parameters ◽  
Save Energy ◽  
Walking Speeds ◽  
The Cost

Background: Gait slowing is a common feature of Parkinson’s disease (PD). Many therapies aim to improve gait speed in persons with PD, but goals are often imprecise. How fast should each patient walk? And how do persons with PD benefit from walking faster? There is an important need to understand how walking speed affects fundamental aspects of gait—including energy cost and stability—that could guide individualized therapy decisions in persons with PD. Objective: We investigated how changes in walking speed affected energy cost and spatiotemporal gait parameters in persons with PD. We compared these effects between dopaminergic medication states and to those observed in age-matched control participants. Methods: Twelve persons with PD and twelve control participants performed treadmill walking trials spanning at least five different speeds (seven speeds were desired, but not all participants could walk at the fastest speeds). Persons with PD participated in two walking sessions on separate days (once while optimally medicated, once after 12-hour withdrawal from dopaminergic medication). We measured kinematic and metabolic data across all trials. Results: Persons with PD significantly reduced energy cost by walking faster than their preferred speeds. This held true across medication conditions and was not observed in control participants. The patient-specific walking speeds that reduced energy cost did not significantly affect gait variability metrics (used as proxies for gait stability). Conclusion: The gait slowing that occurs with PD results in energetically suboptimal walking. Rehabilitation strategies that target patient-specific increases in walking speed could result in a less effortful gait.

An Optimal Working Function Based on the Energetic Cost for Myriapod Robot Systems: How Many Legs Are Optimal for a Centipede?

2005 ◽  
Vol 11 (10) ◽  
pp. 1235-1251 ◽  
Author(s):  
B. T. Nohara ◽  
T. Nishizawa
Keyword(s):  
High Performance ◽  
Point Of View ◽  
Energetic Cost ◽  
Minimum Problem ◽  
Governing Equations ◽  
Robot System ◽  
Cost Of Transport ◽  
Robot Systems ◽  
Optimal Functions ◽  
The Cost

The objective of this paper is to obtain working functions for the legs of a myriapod robot from a kinetic energy point of view. The realization of the high performance of energy consumption is indispensable in the battery-based robot system. We introduce the cost of transport and reduce to the minimum problem of the cost of transport. The calculus of variations is applied to obtain governing equations and the functions for legs. We obtain optimal functions for legs in an octarupedal robot.

Digging energetics in the South American rodent Ctenomys talarum (Rodentia, Ctenomyidae)

2002 ◽  
Vol 80 (12) ◽  
pp. 2144-2149 ◽  
Author(s):  
Facundo Luna ◽  
C Daniel Antinuchi ◽  
Cristina Busch
Keyword(s):  
Metabolic Rate ◽  
Energy Cost ◽  
Resting Metabolic Rate ◽  
Energetic Cost ◽  
Soil Conditions ◽  
Natural Soil ◽  
Subterranean Rodents ◽  
South American ◽  
Ctenomys Talarum ◽  
The Cost

Ctenomys is the most speciose among subterranean rodents. There are few studies on energetics of Ctenomys, and none of them have focused on the energetics of digging. The present study aims to quantify the energetic cost of burrowing in Ctenomys talarum in natural soil conditions and to compare the energetics data with those reported for other subterranean rodents. Digging metabolic rate (DMR) in gravelly sand for C. talarum was 337.4 ± 65.9 mL O2·h–1 (mean ± SD). No differences in DMR were detected between sexes. Moreover, DMR was 295.9% of resting metabolic rate. In terms of a cost of burrowing model, the mass of soil removed per distance burrowed (Msoil) in gravelly sand was 44.5 ± 6.7 g·cm–1. Coefficients of the equation that related the energy cost of constructing a burrow segment of length S and Msoil(Eseg/Msoil) were Ks = 0.33 ± 0.32 J·g–1, which is the energy cost of shearing 1 g of soil, and Kp = 0.0055 ± 0.0042 J·g–1·cm–1, which is the energy cost of pushing 1 g of soil 100 cm. Regarding the cost of burrowing model, our data showed that C. talarum has the lowest DMR in gravelly sand among unrelated subterranean rodents analyzed. Moreover, despite C. talarum feeding aboveground, the foraging economics was similar that of to other rodents.

Stride management assist exoskeleton vs functional gait training in stroke

Neurology ◽  
2018 ◽  
Vol 92 (3) ◽  
pp. e263-e273 ◽  
Author(s):  
Arun Jayaraman ◽  
Megan K. O'Brien ◽  
Sangeetha Madhavan ◽  
Chaithanya K. Mummidisetty ◽  
Heidi R. Roth ◽  
...  
Keyword(s):  
Clinical Outcomes ◽  
Walking Speed ◽  
Rectus Femoris ◽  
Gait Training ◽  
Chronic Stroke ◽  
Leg Muscles ◽  
Lower Limb Muscles ◽  
Walking Speeds ◽  
Functional Gait ◽  
Walking Endurance

ObjectiveTo test the hypothesis that gait training with a hip-assistive robotic exoskeleton improves clinical outcomes and strengthens the descending corticospinal drive to the lower limb muscles in persons with chronic stroke.MethodsFifty participants completed the randomized, single-blind, parallel study. Participants received over-ground gait training with the Honda Stride Management Assist (SMA) exoskeleton or intensity-matched functional gait training, delivered in 18 sessions over 6–8 weeks. Performance-based and self-reported clinical outcomes were measured at baseline, midpoint, and completion, and at a 3-month follow-up. Corticomotor excitability (CME) of 3 bilateral leg muscles was measured using transcranial magnetic stimulation.ResultsThe primary outcome, walking speed, improved for the SMA group by completion of the program (0.24 ± 0.14 m/s difference, p < 0.001). Compared to the functional group, SMA users had greater improvement in walking endurance (46.0% ± 27.4% vs 35.7% ± 20.8%, p = 0.033), took more steps during therapy days (4,366 ± 2,426 vs 3,028 ± 1,510; p = 0.013), and demonstrated larger changes in CME of the paretic rectus femoris (178% ± 75% vs 33% ± 32%, p = 0.010). Participants with hemorrhagic stroke demonstrated greater improvement in balance when using the SMA (24.7% ± 20% vs 6.8% ± 6.7%, p = 0.029).ConclusionsGait training with the SMA improved walking speed in persons with chronic stroke, and may promote greater walking endurance, balance, and CME than functional gait training.Clinicaltrials.gov identifierNCT01994395.Classification of evidenceThis study provides Class I evidence that gait training with a hip-assistive exoskeleton increases clinical outcomes and CME in persons with chronic stroke, but does not significantly improve walking speeds compared to intensity-matched functional gait training.

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