Figures and data in How human runners regulate footsteps on uneven terrain

Version of Record: March 21, 2023
Accepted Manuscript: February 22, 2023

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Nihav Dhawale

Madhusudhan Venkadesan

(2023)
How human runners regulate footsteps on uneven terrain

eLife 12:e67177.

https://doi.org/10.7554/eLife.67177
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Figures
Tables
Additional files

7 figures, 3 tables and 1 additional file

Figures

Figure 1

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Uneven terrain experiments.

(a) We conducted human-subject experiments on flat and uneven terrain while recording biomechanical and metabolic data. The reflective markers and the outline of the force plate are digitally …

Figure 1—source data 1 Dimensional mass and leg length of every subject.: https://cdn.elifesciences.org/articles/67177/elife-67177-fig1-data1-v2.csv
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Figure 2

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Details of the experiment design.

(a) Schematic of the running track, camera placement, force plate positions and the LED strip with a 3 m illuminated section. (b) The terrain was designed so that the range of its height …

Figure 3 with 1 supplement

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Foot placement analysis.

(a) Red circles denote footstep locations (392 footsteps) in the ‘ $x - y$ ’ plane for a representative trial on uneven II. The grid spacing is 190 mm along the length of the track and 95 mm along its …

Figure 3—source data 1 Footstep counts for each subject on all terrain.: https://cdn.elifesciences.org/articles/67177/elife-67177-fig3-data1-v2.pdf
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Figure 3—figure supplement 1

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Subject-wise foot placement patterns.

Heatmaps of the foot placement index for all subjects on each terrain. Each cell has an area of 190 mm × 95 mm, with the longer side along the length of the track. Color bar at the bottom right of …

Figure 4

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Model for estimating fore-aft collision impulses from kinematic data.

(a) A four-link model of the foot (**A–B**), shank (**B–C**), thigh (**C–D**), and torso (**D–N**) moving with center of mass velocity $v_{G}^{-}$ and angular velocity $Ω^{-}$ collides with the ground at angle $θ$ . (G) represents …

Figure 5 with 3 supplements

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Foot placement on uneven terrain.

Histogram of the interquartile range of heights ( $h_{I Q R}$ ) at footstep locations for the directed sampling scheme (red), experiments (yellow), and the blind sampling scheme (blue) on (a) uneven I (2526 …

Figure 5—source data 1 Output of the Markov chain sampling (directed scheme) of the Uneven I terrain.: https://cdn.elifesciences.org/articles/67177/elife-67177-fig5-data1-v2.csv
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Figure 5—source data 2 Output of the Markov chain sampling (directed scheme) of the Uneven II terrain.: https://cdn.elifesciences.org/articles/67177/elife-67177-fig5-data2-v2.csv
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Figure 5—source data 3 Output of the uniform random sampling (blind scheme) of the Uneven I terrain.: https://cdn.elifesciences.org/articles/67177/elife-67177-fig5-data3-v2.csv
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Figure 5—source data 4 Output of the uniform random sampling (blind scheme) of the Uneven II terrain.: https://cdn.elifesciences.org/articles/67177/elife-67177-fig5-data4-v2.csv
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Figure 5—source data 5 Subject-wise, per-step data of the terrain height at foot landing locations on the Uneven I terrain.: https://cdn.elifesciences.org/articles/67177/elife-67177-fig5-data5-v2.csv
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Figure 5—source data 6 Subject-wise, per-step data of the terrain height at foot landing locations on the Uneven II terrain.: https://cdn.elifesciences.org/articles/67177/elife-67177-fig5-data6-v2.csv
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Figure 5—figure supplement 1

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Subject-wise foot placement analysis on uneven I.

Histograms of the interquartile range of heights $(h_{I Q R})$ at the footstep locations for the directed sampling scheme (red), each subject from the experiments (yellow), and the blind sampling scheme (blue).

Figure 5—figure supplement 2

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Subject-wise foot placement analysis on uneven II.

Histograms of the interquartile range of heights $(h_{I Q R})$ at the footstep locations for the directed sampling scheme (red), each subject from the experiments (yellow), and the blind sampling scheme (blue).

Figure 5—figure supplement 3

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Subject-wise foot placement analysis.

Foot placement index $p_{i, j}$ plotted against the median height of the terrain cell and the interquartile range of heights within the terrain cell at landing for all recorded steps on uneven I and uneven …

Figure 6 with 1 supplement

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Regulation of fore-aft impulses.

(a) The fore-aft impulse $J_{y}^{*}$ (gray shaded area) is found by integrating the measured fore-aft ground reaction force $F_{y}$ (black curve) during the deceleration phase. (b) Mean $\frac{J_{y}^{*}}{m v_{y}}$ for 9 subjects on 3 …

Figure 6—source data 1 Subject-wise, per-step data of fore-aft impulse, foot speed, and touchdown angle.: https://cdn.elifesciences.org/articles/67177/elife-67177-fig6-data1-v2.csv
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Figure 6—source data 2 Per-step data of the measured and predicted fore-aft impulse for the compliant and stiff-leg collision models.: https://cdn.elifesciences.org/articles/67177/elife-67177-fig6-data2-v2.csv
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Figure 6—figure supplement 1

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Detailed results of the collision analysis.

Measured $j_{y}^{*} / (m v_{y})$ (blue circles: flat, red circles: uneven I, green circles: uneven II) and calculated $j_{y}^{*} / (m v_{y})$ values for the collision model with a compliant leg (dark gray squares) and rigid leg (light gray …

Figure 7 with 2 supplements

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Energetics and stepping kinematics.

(a) Box plot of the mean forward foot speed at landing (units of froude number). (b) Box plot of the median step width (normalized to leg length). (c) Box plot of the step width variability. Central …

Figure 7—source data 1 Subject-wise, per-step data on step width.: https://cdn.elifesciences.org/articles/67177/elife-67177-fig7-data1-v2.csv
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Figure 7—figure supplement 1

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Subject-wise step width statistics.

Step width is expressed as percent leg length (LL). Because the data are skewed with long tails away from zero, we report the median and interquartile range as measures of the central tendency and …

Figure 7—figure supplement 2

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Representative respirometry data.

Breath-by-breath respirometry data for a representative subject running on uneven II. Red stars represent O₂ consumption rate and green octagons represent CO₂ production rate.

Tables

Table 1

Correlation between landing probability and terrain unevenness.

Independent variable	DenDF	F-value	p-Value
IQR terrain height	20.6	3.03	0.10

Table 1—source data 1 Subject-wise statistics of the terrain’s height in heel-sized patches and the probability of stepping in that patch.: https://cdn.elifesciences.org/articles/67177/elife-67177-table1-data1-v2.csv
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Table 2

Kinematic variables on different terrain types reported as mean ± SD, except for meander values which are reported as median ± interquartile range.

Variable	Flat	Uneven I	Uneven II	F-value	p-Value
Net metabolic rate (W/kg)	$13.1 \pm 0.5$	$13.7 \pm 0.9$	$13.7 \pm 0.8$	2.97	0.08
Median step width (%LL)	$3.9 \pm 1.9$	$4.1 \pm 1.5$	$4.7 \pm 2.0$	4.53	0.03
IQR step width (% LL)	$3.9 \pm 1.4$	$4.3 \pm 0.9$	$5.0 \pm 1.2$	3.65	0.05
Mean step width (%LL)	$4.2 \pm 1.7$	$4.7 \pm 1.6$	$5.2 \pm 1.7$	8.69	0.003
SD step width (% LL)	$2.8 \pm 0.8$	$3.4 \pm 0.6$	$3.6 \pm 0.6$	5.54	0.01
Mean step length (%LL)	$128 \pm 6$	$126 \pm 9$	$125 \pm 9$	1.07	0.37
SD step length (%LL)	$6 \pm 1$	$7 \pm 4$	$6 \pm 1$	0.64	0.54
Mean meander ( $\times 10^{- 4}$ )	$3.21 \pm 2.59$	$3.97 \pm 1.65$	$4.88 \pm 4.62$	1.48	0.25
SD meander ( $\times 10^{- 4}$ )	$0.67 \pm 0.53$	$1.33 \pm 1.40$	$1.27 \pm 2.78$	1.58	0.23
Mean fwd. foot speed (froude num.)	$0.53 \pm 0.17$	$0.36 \pm 0.10$	$0.37 \pm 0.12$	13.08	0.0004
SD fwd. foot speed (froude num.)	$0.17 \pm 0.05$	$0.14 \pm 0.05$	$0.18 \pm 0.07$	1.48	0.26
Mean CoM speed (m/s)	$3.24 \pm 0.07$	$3.21 \pm 0.07$	$3.18 \pm 0.09$	2.32	0.13
SD CoM speed (m/s)	$0.11 \pm 0.03$	$0.13 \pm 0.04$	$0.12 \pm 0.03$	2.00	0.17
Mean touchdown leg length (%LL)	$120 \pm 5$	$119 \pm 4$	$119 \pm 4$	4.28	0.03
SD touchdown leg length (%LL)	$1.1 \pm 0.7$	$0.9 \pm 0.3$	$1.3 \pm 1.2$	1.32	0.29
Mean touchdown leg angle (rad)	$0.20 \pm 0.02$	$0.20 \pm 0.02$	$0.21 \pm 0.02$	3.90	0.04
SD touchdown leg angle (rad)	$0.03 \pm 0.02$	$0.02 \pm 0.003$	$0.03 \pm 0.02$	2.10	0.15

Table 2—source data 1 Subject-wise, per-step data on foot and leg kinetics and kinematics.: https://cdn.elifesciences.org/articles/67177/elife-67177-table2-data1-v2.csv
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Table 3

Details of the ANCOVAs performed on the linear model described in Equation 11 showing the denominator degrees of freedom, F-value and p-value for the fixed terrain factor, and the estimated slopes $β_{f}$ for the fixed forward foot speed effect.

Dependent variable	Factor	DenDF	F-value	p-Value	$β_{f}$
Touchdown leg angle	Terrain	193	1.48	0.23	-
	Fwd. foot speed	38	115.83	<0.0001	0.07±0.01 rad
Fore-aft impulse	Terrain	79	1.45	0.24	-
	Fwd. foot speed	78	12.83	0.001	0.01±0.003