scholarly journals Preferred walking speed on rough terrain; is it all about energetics?

2018 ◽  
Author(s):  
Koren Gast ◽  
Rodger Kram ◽  
Raziel Riemer
Keyword(s):  
Objective Function ◽  
Energy Minimization ◽  
Walking Speed ◽  
Metabolic Energy ◽  
Rough Terrain ◽  
Cost Of Transport ◽  
Unit Distance ◽  
Summary Statement ◽  
Natural Terrain ◽  
Metabolic Energy Expenditure

AbstractHumans have evolved the ability to walk very efficiently. Further, humans prefer to walk at speeds that approximately minimize their metabolic energy expenditure per unit distance (i.e. gross cost of transport, COT). This has been found in a variety of population groups and other species. However, these studies were performed on smooth, level ground or on treadmills. We hypothesized that the objective function for walking is more complex than only minimizing the COT. To test this idea, we compared the preferred speeds and the relationships between COT and speed for people walking on both a smooth, level floor and a rough, natural terrain trail. Rough terrain presumably introduces other factors, such as stability, to the objective function. 10 healthy men walked on both a straight, flat, smooth floor and on an outdoor trail strewn with rocks and boulders. In both locations, subjects performed 6-8 trials at different speeds relative to their preferred speed. The COT-speed relationships were similarly U-shaped for both surfaces, but the COT values on rough terrain were approximately 215% greater. On the smooth surface, the preferred speed (1.24+/-0.14 m/sec) was 5.1% faster (p>0.05) than the speed that minimized COT (1.18 m/sec) but on rough terrain, the preferred speed (1.06+/-0.07 m/sec) was 6.2% slower (p>0.05) than the COT minimum speed (1.13 m/sec). This suggests that the objective function when walking on rough terrain includes additional factors such as stability.Summary statement: On rough terrain, humans do not choose their walking speed based on metabolic energy minimization alone.

The cost of transport of human running is not affected, as in walking, by wide acceleration/deceleration cycles

2013 ◽  
Vol 114 (4) ◽  
pp. 498-503 ◽  
Author(s):  
Alberto E. Minetti ◽  
Paolo Gaudino ◽  
Elena Seminati ◽  
Dario Cazzola
Keyword(s):  
Field Experiments ◽  
Metabolic Cost ◽  
Constant Speed ◽  
Metabolic Energy ◽  
Recent Theory ◽  
Cost Of Transport ◽  
Unit Distance ◽  
The Cost ◽  
Speed Fluctuations ◽  
Human Running

Although most of the literature on locomotion energetics and biomechanics is about constant-speed experiments, humans and animals tend to move at variable speeds in their daily life. This study addresses the following questions: 1) how much extra metabolic energy is associated with traveling a unit distance by adopting acceleration/deceleration cycles in walking and running, with respect to constant speed, and 2) how can biomechanics explain those metabolic findings. Ten males and ten females walked and ran at fluctuating speeds (5 ± 0, ± 1, ± 1.5, ± 2, ± 2.5 km/h for treadmill walking, 11 ± 0, ± 1, ± 2, ± 3, ± 4 km/h for treadmill and field running) in cycles lasting 6 s. Field experiments, consisting of subjects following a laser spot projected from a computer-controlled astronomic telescope, were necessary to check the noninertial bias of the oscillating-speed treadmill. Metabolic cost of transport was found to be almost constant at all speed oscillations for running and up to ±2 km/h for walking, with no remarkable differences between laboratory and field results. The substantial constancy of the metabolic cost is not explained by the predicted cost of pure acceleration/deceleration. As for walking, results from speed-oscillation running suggest that the inherent within-stride, elastic energy-free accelerations/decelerations when moving at constant speed work as a mechanical buffer for among-stride speed fluctuations, with no extra metabolic cost. Also, a recent theory about the analogy between sprint (level) running and constant-speed running on gradients, together with the mechanical determinants of gradient locomotion, helps to interpret the present findings.

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.

scholarly journals Rough substrates constrain walking speed in ants through modulation of stride frequency and not stride length

2019 ◽  
Author(s):  
G.T. Clifton ◽  
D. Holway ◽  
N. Gravish
Keyword(s):  
Stride Length ◽  
Field Experiments ◽  
Walking Speed ◽  
Stride Frequency ◽  
Rough Terrain ◽  
Flat Substrate ◽  
Walking Performance ◽  
Natural Terrain ◽  
Kinematic Mechanisms ◽  
Walking Speeds

AbstractNatural terrain is rarely flat. Substrate irregularities challenge walking animals to maintain stability, yet we lack quantitative assessments of walking performance and limb kinematics on naturally rough ground. We measured how continually rough 3D-printed substrates influence walking performance of Argentine ants by measuring walking speeds of workers from lab colonies and by testing colony-wide substrate preference in field experiments. Tracking limb motion in over 8,000 videos, we used statistical models that associate walking speed with limb kinematic parameters to compare movement over flat versus rough ground. We found that rough substrates reduced preferred and peak walking speeds by up to 42% and that ants actively avoided rough terrain in the field. Observed speed reductions were modulated primarily by shifts in stride frequency and not stride length, a pattern consistent across flat and rough substrates. Modeling revealed that walking speeds on rough substrates were accurately predicted based on flat walking data for over 89% of strides. Those strides that were not well modeled primarily involved limb perturbations, including missteps, active foot repositioning, and slipping. Together these findings relate kinematic mechanisms underlying walking performance on rough terrain to ecologically-relevant measures under field conditions.

scholarly journals Energy expenditure does not explain step length-width choices during walking

2021 ◽  
Author(s):  
Stephen A Antos ◽  
Konrad P Kording ◽  
Keith E Gordon
Keyword(s):  
Energy Expenditure ◽  
Walking Speed ◽  
Step Length ◽  
Metabolic Energy ◽  
Step Width ◽  
Energy Expenditures ◽  
Length Width ◽  
Metabolic Energy Expenditure ◽  
Least Energy ◽  
Trial Participants

Healthy young adults have a most preferred walking speed, step length, and step width that are close to energetically optimal. However, people can choose to walk with a multitude of different step lengths and widths, which can vary in both energy expenditure and preference. Here we further investigate step length-width preferences and their relationship to energy expenditure. In line with a growing body of research, we hypothesized that people's preferred stepping patterns would not be fully explained by metabolic energy expenditure. To test this hypothesis we used a two-alternative forced-choice paradigm. Fifteen participants walked on an oversized treadmill. Each trial participants experienced two stepping patterns and then chose the pattern they preferred. Over time, we adapted the choices such that there was 50% chance of choosing one pattern over another (equally preferred). If people's preferences are based solely on metabolic energy expenditure, then these equally preferred stepping patterns should have equal energy expenditure. We found that energy expenditure differed across equally preferred step length-width patterns (p < 0.001). On average, longer steps with higher energy expenditures were preferred over shorter and wider steps with lower energy expenditures (p < 0.001). We also asked participants to rank a set of shorter, wider, and longer steps from most preferred to least preferred, and from most energy expended to least energy expended. Only 7/15 participants had the same rankings for their preferences and perceived energy expenditure. Our results suggest that energy expenditure is not the only factor influencing a person's conscious gait choices.

Joint-Space Dynamic Model of Metabolic Cost With Subject-Specific Energetic Parameters

2014 ◽  
Author(s):  
Dustyn Roberts ◽  
Howard Hillstrom ◽  
Joo H. Kim
Keyword(s):  
Dynamic Model ◽  
Metabolic Cost ◽  
Joint Space ◽  
Human Motion ◽  
Metabolic Energy ◽  
Model Parameters ◽  
Cost Of Transport ◽  
Walking Speeds ◽  
The Cost ◽  
Metabolic Energy Expenditure

Metabolic energy expenditure (MEE) is commonly used to characterize human motion. In this study, a general joint-space dynamic model of MEE is developed by integrating the principles of thermodynamics and multibody system dynamics in a joint-space model that enables the evaluation of MEE without the limitations inherent in experimental measurements or muscle-space models. Muscle-space energetic components are mapped to the joint space, in which the MEE model is formulated. A constrained optimization algorithm is used to estimate the model parameters from experimental walking data. The joint-space parameters estimated directly from active subjects provide reliable estimates of the trend of the cost of transport at different walking speeds. The quantities predicted by this model, such as cost of transport, can be used as strong complements to experimental methods to increase the reliability of results and yield unique insights for various applications.

scholarly journals Economical and preferred walking speed using body weight support apparatus with a spring-like characteristics

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Daijiro Abe ◽  
Shunsuke Sakata ◽  
Kiyotaka Motoyama ◽  
Naoki Toyota ◽  
Hidetsugu Nishizono ◽  
...  
Keyword(s):  
Body Weight ◽  
Walking Speed ◽  
Body Weight Support ◽  
Cost Of Transport ◽  
Unit Distance ◽  
Young Males ◽  
Reduced Body ◽  
Weight Support ◽  
The Individual ◽  
Walking Speeds

Abstract Background A specific walking speed minimizing the U-shaped relationship between energy cost of transport per unit distance (CoT) and speed is called economical speed (ES). To investigate the effects of reduced body weight on the ES, we installed a body weight support (BWS) apparatus with a spring-like characteristics. We also examined whether the 'calculated' ES was equivalent to the 'preferred' walking speed (PWS) with 30% BWS. Methods We measured oxygen uptake and carbon dioxide output to calculate CoT values at seven treadmill walking speeds (0.67–2.00 m s− 1) in 40 healthy young males under normal walking (NW) and BWS. The PWS was determined under both conditions on a different day. Results A spring-like behavior of our BWS apparatus reduced the CoT values at 1.56, 1.78, and 2.00 m s− 1. The ES with BWS (1.61 ± 0.11 m s− 1) was faster than NW condition (1.39 ± 0.06 m s− 1). A Bland-Altman analysis indicated that there were no systematic biases between ES and PWS in both conditions. Conclusions The use of BWS apparatus with a spring-like behavior reduced the CoT values at faster walking speeds, resulting in the faster ES with 30% BWS compared to NW. Since the ES was equivalent to the PWS in both conditions, the PWS could be mainly determined by the metabolic minimization in healthy young males. This result also derives that the PWS can be a substitutable index of the individual ES in these populations.

scholarly journals Influence of Arm Swing on Cost of Transport during Walking

2018 ◽  
Author(s):  
Myriam L. de Graaf ◽  
Juul Hubert ◽  
Han Houdijk ◽  
Sjoerd M. Bruijn
Keyword(s):  
Angular Momentum ◽  
Metabolic Energy ◽  
Energetic Cost ◽  
Healthy Individuals ◽  
Cost Of Transport ◽  
Arm Swing ◽  
Significant Difference ◽  
Summary Statement ◽  
The Cost ◽  
Healthy Participants

ABSTRACTNormal arm swing plays a role in decreasing the cost of transport during walking. However, whether excessive arm swing can reduce the cost of transport even further is unknown. Therefore, we tested the effects of normal and exaggerated arm swing on the cost of transport in the current study. Healthy participants (n=12) walked on a treadmill (1.25 m/s) in seven trials with different arm swing amplitudes (in-phase, passive restricted, active restricted, normal, three gradations of extra arm swing), while metabolic energy cost and the vertical angular momentum (VAM) and ground reaction moment (GRM) were measured.In general, VAM and GRM decreased as arm swing amplitude was increased, except for in the largest arm swing amplitude condition. The decreases in VAM and GRM were accompanied by a decrease in cost of transport from in-phase walking (negative amplitude) up to a slightly increased arm swing (non-significant difference compared to normal arm swing). The most excessive arm swings led to an increase in the cost of transport, most likely due to the cost of swinging the arms. In conclusion, increasing arm swing amplitude leads to a reduction in vertical angular moment and ground reaction moments, but it does not lead to a reduction in cost of transport for the most excessive arm swing amplitudes. Normal or slightly increased arm swing amplitude appears to be optimal in terms of cost of transport in young and healthy individuals.SUMMARY STATEMENTExcessive arm swing reduces the vertical angular momentum and ground reaction moment, but not necessarily the energetic cost of transport.

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.

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