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Cited by 58Lower Extremity Biomechanics and PathologiesBalance, Gait, and Falls PreventionRobotic Locomotion and Control

The DOI matches its Crossref record; 45 of the 46 references it cites were found in a registry or an index; none of the 59 sources its claims cite is checked for support yet.

Preferred walking speed on rough terrain: is it all about energetics?

Open access
Gast, Koren, Kram, Rodger, Riemer, Raziel·2019·Journal of Experimental Biology
DOI 10.1242/jeb.185447

Published version of a preprint

Open this paper in CoChat — free accountOpen PDF

Abstract

Humans 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 mostly 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 5-7 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 115% greater. On the smooth surface, the preferred speed (1.24+/−0.17 m/sec) was found to be statistically not different (p-value =0.09) than the speed that minimized COT (1.34 +/− 0.03 m/sec). On rough terrain, the preferred speed (1.07+/−0.05 m/sec) was slower than the COT minimum speed (1.13 +/− 0.07 m/sec) and was statistical significant (p-value=0.02). Since near the optimum speed the COT function is very shallow, these changes in speed result in small change in COT (0.5%). It appears that the objective function for speed preference when walking on rough terrain includes COT and additional factors such as stability.

Overview

AI snapshot

Written from the paper’s full text.

TL;DR

This study compared preferred walking speed and metabolic cost of transport (COT) on a smooth, level floor versus a natural rough trail. On rough terrain, preferred speed was significantly slower than the COT-minimizing speed, suggesting walking-speed preference is not explained by energetics alone.

Key findings

  • COT–speed relationships were U-shaped on both surfaces, but COT on rough terrain was approximately 115% greater than on the smooth floor.
  • On the smooth floor, preferred speed (1.24±0.17 m s⁻¹) was not statistically different from the COT-minimizing speed (1.34±0.03 m s⁻¹; P=0.09).
  • On rough terrain, preferred speed (1.07±0.05 m s⁻¹) was significantly slower than the COT-minimizing speed (1.13±0.07 m s⁻¹; P=0.02).
  • Because the COT function is shallow near the optimum, these speed differences changed COT by only 0.8% on the smooth floor and 0.3% on rough terrain; normalized COT–speed curves were similar despite a significant Chow test (P=0.003; meaningful coefficient 0.84).

Methods

  • Ten healthy men (body mass 75.10±11.64 kg, height 1.82±0.07 m, age 27.5±1.6 years) walked on a 44.0 m smooth, level concrete floor and a 67.0 m rough outdoor trail with rocks and boulders (straight-line distance 60.3 m; maximum elevation amplitude <2 m).
  • Subjects performed trials at preferred, very slow (~50%), slow (~75%), fast (~120–150%), and maximum (~140–190%) speeds; six trials on smooth floor and seven on rough terrain, each 7–9 min, with 5-min rests. Only the second rough-terrain session was analyzed to avoid learning effects.
  • Metabolic rate was measured with a portable K4b2 indirect calorimetry system; COT was calculated as MR/(speed×body mass). Only RER<1 trials were analyzed, steady-state measurements were taken at least 3 min after start, and full out-and-back laps were averaged. Linear mixed models with polynomial orders 1–4 were selected by BIC, and Chow tests, paired t-tests, and a meaningful coefficient were used for comparisons.

Limitations

  • The authors state they did not model or measure stability on rough terrain as a function of speed, and they do not claim their proposed objective function is the only possible explanation; slower rough-terrain walking might also reflect the need for more accurate foot placement.
  • The sample was small and restricted to ten healthy men, so findings may not generalize to women, older adults, or clinical populations (evident from the text).
  • The rough-terrain condition required practice and only the second session was used; trials were excluded for RER>1, a fall, and recording failure, and the specific trail may limit generalization to other rough surfaces (evident from the text).

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1242/jeb.185447

Cites

45 of 45 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Verification

Claims the paper makes

0 of 59 cited sources checked · 0 supported · 0 flagged

Verify all 4 references — free account
  • Findingown data

    On rough terrain, the preferred speed (1.07±0.05 m/s) was significantly slower than the COT minimum speed (1.13±0.07 m/s; P=0.02).

    “On rough terrain, the preferred speed (1.07±0.05m s -1 ) was significantly slower than the COT minimum speed (1.13±0.07m s -1 ; P=0.02).”
    Quote in the paperSubstantial claim
  • Findingown data

    The COT-speed relationships were similarly U-shaped for both the smooth floor and rough terrain.

    “The COT-speed relationships were similarly U-shaped for both surfaces, but the COT values on rough terrain were approximately 115% greater.”
    • Also stated in: § COT · plain
      “For both surfaces, the best fit to the data (i.e.lowest BIC; Appendix 2, Table A2) was of the form COT(s)=bs 2 +cs+d”
    Quote in the paperSubstantial claim
  • Findingown data

    COT values on rough terrain were approximately 115% greater than on the smooth floor.

    “but the COT values on rough terrain were approximately 115% greater.”
    • Also stated in: § COT · plain
      “We found that the average COT values for the rough terrain were approximately 115% greater than those obtained for the smooth floor condition.”
    • Also stated in: § DISCUSSION · plain
      “The COT for the rough terrain was considerably greater (∼115%) than for smooth, level walking”
    Quote in the paperSubstantial claim
  • Findingown data

    On the smooth surface, the preferred speed (1.24±0.17 m/s) was not statistically different (P=0.09) from the speed that minimized COT (1.34±0.03 m/s).

    “On the smooth surface, the preferred speed (1.24±0.17m s -1 ) was not found to be statistically different (P=0.09)than the speed that minimized COT (1.34±0.03m s -1 ).”
    • Also stated in: § COT · plain
      “For the smooth floor condition, a paired t-test showed no significant difference between the preferred and optimal speeds (P=0.09)”
    Quote in the paperSubstantial claim
  • Findingown data

    Subjects' preferred speeds on both surfaces were close to the speeds that minimized COT.

    “Our results revealed that, similar to past studies that studied COT on smooth, level ground and treadmills (e.g.Ralston, 1958;Zarrugh et al., 1974), the subjects' preferred speeds on both surfaces were close to the speeds that minimized COT.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Ralston, 1958 source
    • cites Zarrugh et al., 1974 source
  • It may state two separate claims as one. 22
  • The quote only partly states this claim. 3
  • Probably not a substantial claim. 23

  • It may state two separate claims as one. The quote only partly states this claim.

    Findingown data

    In a pilot study, there was a learning effect and it took approximately 25 min of practice before the COT stabilized on rough terrain.

    “In a pilot study, we found that there was a learning effect and that it took approximately 25 min of practice before the COT stabilized.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.

    Findingown data

    The actual walking path was relatively straight but had some small elevation and left-right deviations.

    “The actual walking path was relatively straight but had some small elevation and left-right deviations.”
    Quote in the paperNot a substantial claim

  • It may state two separate claims as one.

    Findingown data

    The fit based on the formulation of Ralston (1958), tested using polynomials of orders 2 to 4, had higher BIC values, meaning the fit was worse.

    “This was tested using the polynomials of orders 2 to 4, yet BIC values were higher, meaning the fit was worse.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Ralston, 1958 source

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Findingown data

    The maximum elevation amplitude along the trail was less than 2 m.

    “We measured the changes in elevation along the trail and found that the maximum elevation amplitude was less than 2 m (Fig. 1A).”
    Quote in the paperNot a substantial claim

  • It may state two separate claims as one.

    Findingown data

    The preferred speed on the smooth floor was, on average, 8% slower than the optimum speed, but the difference was not statistically significant (P=0.09).

    “The preferred speed on the smooth floor was, on average, 8% slower than the optimum speed, but the difference was not statistically significant (P=0.09).”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingown data

    The prediction equation of Givoni and Goldman (1971) had the best match to our rough terrain data (lowest RMSE), although the Pandolf et al. (1977) equation is used more commonly.

    “Note that although the Pandolf et al. (1977) equation is used more commonly, the prediction equation of Givoni and Goldman (1971) had the best match to our rough terrain data (lowest RMSE).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Pandolf et al., 1977 source
    • cites Givoni and Goldman, 1971 source

  • Probably not a substantial claim.

    Findingnone given

    The trail comprised some naturally scattered rocks and boulders.

    “The trail comprised some naturally scattered rocks and boulders (Fig. 1B; for a short video of a subject walking, see Movie 1).”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingown data

    In a pilot study, the protocol of walking at preferred, maximum and very slow speeds accelerated learning and reduced adaptation time.

    “In a pilot study, we found that this protocol accelerated learning and reduced adaptation time.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingown data

    The meaningful coefficient for the normalized data was only 0.84, meaning the average difference between the models is smaller than the average error in the models' predictions.

    “Yet, the meaningful coefficient (Eqn 4) was only 0.84, which means that the average difference between the model is smaller than the average error in the models predictions.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingown data

    Grid search optimization produced terrain factors of 1.9 and 3.1 for Givoni and Goldman (1971) and Pandolf et al. (1977), respectively.

    “This procedure produced terrain factors of 1.9 and 3.1 for Givoni and Goldman (1971) and Pandolf et al. (1977), respectively.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Givoni and Goldman, 1971 source
    • cites Pandolf et al., 1977 source

  • It may state two separate claims as one.

    Findingown data

    The metabolically optimal average speed was 1.34±0.04 m/s on the smooth floor and 1.13±0.07 m/s on rough terrain.

    “The metabolically optimal average speed (the speed that minimizes the fitted COT functions) was 1.34±0.04m s -1 on the smooth floor and 1.13±0.07m s -1 on rough terrain.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Premisecitation

    Humans have evolved the ability to walk very efficiently.

    “Humans have evolved the ability to walk very efficiently.”
    • Also stated in: § INTRODUCTION · plain
      “Humans have evolved the ability to walk very efficiently.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Alexander, 2003

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.

    Premisecitation

    Givoni and Goldman (1971) and Pandolf et al. (1977) developed prediction equations for the metabolic cost of load-carrying while walking on different terrains and slopes.

    “Givoni and Goldman (1971) and Pandolf et al. (1977) developed prediction equations for the metabolic cost of load-carrying while walking on different terrains and slopes.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Givoni and Goldman (1971) source
    • cites Pandolf et al. (1977) source

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Premisecitation

    Over generations, human bodies have evolved muscular and skeletal systems well suited to locomotion.

    “Over generations, our bodies have evolved muscular and skeletal systems well suited to locomotion (Alexander, 2003).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Alexander, 2003

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim. It may state two separate claims as one.

    Premisecitation

    People who are blind and walk without a guide have a slower preferred walking speed that is unlikely to correspond to their COT minimum.

    “However, without a guide, their preferred walking speed is slower and is unlikely to correspond to their COT minimum.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Clark-Carter et al. (1986) source

  • It may state two separate claims as one.

    Interpretationreasoning

    Because near the optimum speed the COT function is very shallow, the changes in speed result in a small change in COT (0.5%).

    “Because near the optimum speed the COT function is very shallow, these changes in speed result in a small change in COT (0.5%).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Premisecitation

    Pedestrians crossing a street increased their walking speed when the time gap between cars was smaller.

    “Kalantarov et al. (2018) found that pedestrians crossing a street increased their walking speed when the time gap between cars was smaller.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Kalantarov et al. (2018) source

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Premisecitation

    A recent study examined the metabolic cost of walking on a treadmill that imitates uneven terrain.

    “A recent study examined the metabolic cost of walking on a treadmill that imitates uneven terrain (Voloshina and Ferris, 2013).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Voloshina and Ferris, 2013

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • It may state two separate claims as one.

    Premisecitation

    Step frequency, step length, step width and speed are all chosen to minimize energy expenditure.

    “For example, it has been shown that step frequency (Zarrugh et al., 1974), step length (Umberger and Martin, 2007), step width (Donelan et al., 2001) and speed (Zarrugh et al., 1974) are all chosen to minimize energy expenditure.”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Zarrugh et al., 1974 source
    • cites Umberger and Martin, 2007 source
    • cites Donelan et al., 2001 source

  • It may state two separate claims as one.

    Premisecitation

    Humans learn and choose to walk in a way that minimizes their metabolic energy expenditure.

    “Further, we learn and choose to walk in a way that minimizes our metabolic energy expenditure (Ralston, 1958;Zarrugh et al., 1974).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Ralston, 1958 source
    • cites Zarrugh et al., 1974 source

  • Probably not a substantial claim.

    Study design and conductnone given

    Only measurements of metabolic rate obtained at least 3 min after the start time were analyzed.

    “Therefore, we only analyzed measurements of metabolic rate that were obtained at least 3 min after the start time.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Study design and conductreasoning

    Using an LMM allowed avoiding the problem of over-fitting the data.

    “This allowed us to avoid the problem of over-fitting the data (e.g.fitting a third-order polynomial to six data points).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim. It may state two separate claims as one.

    Study design and conductreasoning

    To eliminate the possibility of acquiring data during the learning period, subjects completed two rough terrain sessions and only the second session data were used.

    “Therefore, to eliminate the possibility of acquiring data during this learning period, subjects completed two rough terrain sessions during which they performed the full experimental protocol.For our analysis, we used only the second session data.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Premisecitation

    The protocol was inspired by Selinger et al. (2015), who found that to find the optimal step frequency, subjects had to carry out an exploratory session walking at fast and slow step frequencies.

    “The protocol was inspired by Selinger et al. (2015), who studied humans walking with novel exoskeletons and found that in order to find the optimal step frequency, which minimized their metabolic rate, subjects had to carry out an exploratory session in which they walked at fast and slow step frequencies.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Selinger et al. (2015) source

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Study design and conductnone given

    The turbine was calibrated every day and before each trial using a standard authorized calibration gas mixture and a volume pump.

    “Every day and before each trial, the turbine was calibrated using a standard authorized calibration gas mixture and a volume pump.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim. It may be too vague to check against evidence. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.

    Interpretationnone given

    The greater COT values for the rough surface likely reflect other stability-related issues.

    “and/or other stability-related issues.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Premisecitation

    Other species, including wildebeest, elephants and horses, exhibit preferred terrestrial locomotion speeds within each gait.

    “It is worth noting that other species, for example wildebeest (Pennycuick, 1975), elephants (Langman et al., 1995) and horses (Hoyt and Taylor, 1981), also exhibit preferred terrestrial locomotion speeds within each gait.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Pennycuick, 1975 source
    • cites Langman et al., 1995 source
    • cites Hoyt and Taylor, 1981 source

  • It may state two separate claims as one.

    Premisecitation

    Humans can perceive their localized effort, which can be reflected in electromyographic recordings.

    “and their localized effort, which can be reflected in electromyographic recordings (Korol et al., 2014(Korol et al., , 2017)).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Korol et al., 2014 source
    • cites Korol et al., 2017 source

  • Probably not a substantial claim.

    Study design and conductreasoning

    Only trials with a respiratory exchange ratio (RER) of less than 1.00 were analyzed to ensure that metabolic energy was primarily generated via aerobic metabolism.

    “To ensure that the metabolic energy was primarily generated via aerobic metabolism, only trials with a respiratory exchange ratio (RER) of less than 1.00 were analyzed.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim.

    Study design and conductreasoning

    To eliminate the effects of local terrain variation, metabolic rate values were averaged over full out-and-back laps.

    “To eliminate the effects of local terrain variation, we averaged metabolic rate values over full out-and-back laps.”
    Quote in the paperSubstantial claim

  • The quote only partly states this claim.

    Interpretationcitation

    The greater COT values for the rough surface likely reflect shorter step lengths and wider step widths.

    “shorter step lengths and wider step widths (Donelan et al., 2001;Zarrugh et al., 1974)”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Donelan et al., 2001 source
    • cites Zarrugh et al., 1974 source

  • It may state two separate claims as one. The quote only partly states this claim.

    Study design and conductreasoning

    In our case, the fluctuations in walking speed were significantly smaller than in Seethapathi and Srinivasan (2015) and probably had a negligible effect on metabolic expenditure.

    “In our case, the fluctuations in walking speed were significantly smaller and probably had a negligible effect on metabolic expenditure.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Seethapathi and Srinivasan (2015)

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Study design and conductnone given

    Stability was not modeled or measured on rough terrain as a function of speed.

    “It should also be noted that while everyday experience tells us that slower walking increases stability, we did not model or measure stability on rough terrain as a function of speed.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.

    Premisecitation

    Voloshina and Ferris (2013) have shown that walking on uneven terrain causes only minor changes in stepping strategy and suggest that changes in metabolic rate are instead due to a change in the amount of work carried out by lower-limb joints as well as changes in the timing of foot-ground collision and trailing leg push-off.

    “Voloshina and Ferris (2013) have shown that walking on uneven terrain causes only minor changes in stepping strategy and suggest that the changes in metabolic rate are instead due to a change in the amount of work carried out by lower-limb joints as well as changes in the timing of foot-ground collision and trailing leg push-off.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Voloshina and Ferris (2013)

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • It may state two separate claims as one.

    Premisecitation

    The preferred walking speeds of horses and elephants are close to their minimum COT speeds.

    “Further, the preferred walking speeds of horses and elephants also are close to their minimum COT speeds (Hoyt and Taylor, 1981;Langman et al., 1995).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Hoyt and Taylor, 1981 source
    • cites Langman et al., 1995 source

  • Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.

    Study design and conductnone given

    The Ben-Gurion University Human Subjects Research Committee approved the study and participants gave written informed consent.

    “The Ben-Gurion University Human Subjects Research Committee approved the study and participants gave written informed consent.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Premisecitation

    Vision affects the human perception and selection of preferred walking speed.

    “Another sense that affects the human perception and selection of preferred walking speed is vision (Mohler et al., 2007).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Mohler et al., 2007 source

  • It may state two separate claims as one.

    Interpretationown data

    For the normalized data, although the fitted equations are not the same, the normalized COT data for both surfaces show similar behavior as a function of normalized speed.

    “Thus, for the normalized data, although the fitted equations are not the same (Chow test), the normalized COT data for both surfaces show similar behavior as a function of normalized speed.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.

    Study design and conductreasoning

    Trial order was counterbalanced so that half the subjects performed the first sequence and the other half performed the second, to avoid trial order effects.

    “We switched between X and Y (i.e. the fast speeds and the slow speeds) so that half the subjects performed the first sequence while the other half performed the second, to avoid trial order effects.”
    Quote in the paperNot a substantial claim
39 of 39

  • The paper relies on this without support.

    These studies (on preferred speed and COT) were mostly performed on smooth, level ground or on treadmills.

    “However, these studies were mostly performed on smooth, level ground or on treadmills.”

  • The authors state this as an assumption.

    Rough terrain presumably introduces other factors, such as stability, to the objective function.

    “Rough terrain presumably introduces other factors, such as stability, to the objective function.”

  • The paper relies on this without support.

    To date, most research into walking and the COT phenomenon has been carried out on treadmills or smooth, level floors.

    “To date, most research into walking and the COT phenomenon has been carried out on treadmills or smooth, level floors.”

  • The paper relies on this without support.

    No one has examined COT as a function of speed on natural, rough terrain.

    “However, to the best of our knowledge, no one has examined COT as a function of speed on natural, rough terrain.”

  • The paper relies on this without support.

    Human walking efficiency primarily evolved on natural surfaces, not smooth floors or treadmills.

    “First, human walking efficiency primarily evolved on natural surfaces, not smooth floors or treadmills.”

  • The paper relies on this without support.

    Walking on rough terrain intrinsically requires the person to consider their stability while walking.

    “Second, walking on rough terrain intrinsically requires the person to consider their stability while walking.”

  • The paper relies on this without support.

    Slower walking on rough terrain increases stability.

    “while everyday experience tells us that slower walking increases stability, we did not model or measure stability on rough terrain as a function of speed.”
7 of 7

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Reducing step length below that preferred on regular surfaces should increase the energy costs associated with walking on natural terrains like those in forests.

    “Reducing step length below that preferred on regular surfaces should increase the energy costs associated with walking on natural terrains like those in forests (Gast et al., 2019; Umberger & Martin, 2007)”

    From Forest terrains influence walking kinematics among indigenous Tsimane of the Bolivian Amazon (2022) · cites this paper as Gast et al., 2019

  • Recent studies of walking on rocky terrains found individuals significantly reduced their step lengths to achieve more stable foot placement compared with walking on flat, even surfaces, which more than doubled their walking costs.

    “Several recent studies of walking on rocky terrains found the individuals significantly reduced their step lengths to achieve more stable foot placement when compared with walking on flat, even surfaces (Gast, Kram, & Riemer, 2019; Matthis et al., 2018), which more than doubled their walking costs (Gast et al., 2019)”

    From Forest terrains influence walking kinematics among indigenous Tsimane of the Bolivian Amazon (2022) · cites this paper as Gast et al., 2019

  • Cost differences could be closer to the range of the 50-115% increases previously measured for heavy brush and rocky terrains vs. even, hard surfaces.

    “Cost differences could be closer to the range of the 50–115% increases previously measured for heavy brush and rocky terrains vs. even, hard surfaces (Soule & Goldman, 1972; Gast et al., 2019).”

    From Forest terrains influence walking kinematics among indigenous Tsimane of the Bolivian Amazon (2022) · cites this paper as Gast et al., 2019

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Conflicting standard deviations for optimal smooth-floor speed

    Minor

    The abstract reports a standard deviation of 0.03 m s−1, whereas the Results report 0.04 m s−1 for the same optimal speed. Table 1 gives 0.036 m s−1, which rounds to 0.04 at two decimal places.

  • Conflicting average body masses

    Minor

    The subjects' average body mass is reported as 75.10 kg in Methods but as 76.5 kg in the appendix calculations.

2 of 2

Citations

Cites

Flagged first, then by citations

1 of the 46 references couldn’t be matched to a known paper.

Research works printed but not linked: 1

  1. Alexander, 2003, The best way to travel, 1

Cited by

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Related

Metadata

Authors
Gast, K., Kram, R., & Riemer, R.
Affiliations
  • Ben-Gurion University of the Negev (IL)
  • Department of Integrative Physiology, University of Colorado Boulder, USA
Corresponding author
Riemer, Raziel
ORCID
Riemer, Raziel
Venue
Journal of Experimental Biology
Publisher
The Company of Biologists
Published
2019-01-01
Volume
222
Issue
Pt 9
ISSN
  • 0022-0949 (ISSN-L)
  • 1477-9145
DOI
10.1242/jeb.185447
OpenAlex
W2950067380
Cited by
58
References
46
Citations by year
2026: 7 · 2025: 15 · 2024: 6 · 2023: 7 · 2022: 14 · 2021: 5 · 2020: 3 · 2019: 1
FWCI
1.80
Type
journal article
Language
en
Open access
Licence
www.biologists.com/user-licence-1-1/ (am)
Locations
  • Journal of Experimental Biology (publishedVersion)
  • bioRxiv (Cold Spring Harbor Laboratory) (submittedVersion, cc-by)
  • PubMed (publishedVersion)
  • HighWire Press Open Archive (submittedVersion)
Funders
Leona M. and Harry B. Helmsley Charitable Trust and the Marcus Endowment Fund both at Ben-Gurion University of the Negev (through the Agricultural, Biological and Cognitive Robotics Initiative of Ben-Gurion University of the Negev.)
Topics
  • Physical Sciences › Engineering › Biomedical Engineering › Lower Extremity Biomechanics and Pathologies
  • Health Sciences › Health Professions › Physical Therapy, Sports Therapy and Rehabilitation › Balance, Gait, and Falls Prevention
  • Physical Sciences › Engineering › Control and Systems Engineering › Robotic Locomotion and Control
Keywords
preferred walking speed, uneven terrain, cost of transport, metabolic cost, energy cost of walking, gait stability, human locomotion
MeSH terms
Walking Speed, Adult, Energy Metabolism, Environment, Humans, Male

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

A language model drew the claims from the paper on 2026-11-10, under version 3 of the claim definition (model deepseek-v4.1-flash, prompt extract-v3).

A second model labelled each claim on 2026-11-10 (model jev-1.13-20260917, definition revision gold-guideline-v0.2).

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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