scholarly journals Level, Uphill, and Downhill Running Economy Values Are Correlated Except on Steep Slopes

2021 ◽  
Vol 12 ◽  
Author(s):  
Marcel Lemire ◽  
Mathieu Falbriard ◽  
Kamiar Aminian ◽  
Grégoire P. Millet ◽  
Frédéric Meyer

The aim of this study was first to determine if level, uphill, and downhill energy cost of running (ECR) values were correlated at different slopes and for different running speeds, and second, to determine the influence of lower limb strength on ECR. Twenty-nine healthy subjects completed a randomized series of 4-min running bouts on an instrumented treadmill to determine their cardiorespiratory and mechanical (i.e., ground reaction forces) responses at different constant speeds (8, 10, 12, and 14 km·h−1) and different slopes (−20, −10, −5, 0, +5, +10, +15, and +20%). The subjects also performed a knee extensor (KE) strength assessment. Oxygen and energy costs of running values were correlated between all slopes by pooling all running speeds (all r2 ≥ 0.27; p ≤ 0.021), except between the steepest uphill vs. level and the steepest downhill slope (i.e., +20% vs. 0% and −20% slopes; both p ≥ 0.214). When pooled across all running speeds, the ECR was inversely correlated with KE isometric maximal torque for the level and downhill running conditions (all r2 ≥ 0.24; p ≤ 0.049) except for the steepest downhill slope (−20%), but not for any uphill slopes. The optimal downhill grade (i.e., lowest oxygen cost) varied between running speeds and ranged from −14% and −20% (all p < 0.001). The present results suggest that compared to level and shallow slopes, on steep slopes ~±20%, running energetics are determined by different factors (i.e., reduced bouncing mechanism, greater muscle strength for negative slopes, and cardiopulmonary fitness for positive slopes). On shallow negative slopes and during level running, ECR is related to KE strength.

2009 ◽  
Vol 27 (11) ◽  
pp. 1137-1144 ◽  
Author(s):  
Trevor C. Chen ◽  
Kazunori Nosaka ◽  
Ming-Ju Lin ◽  
Hsin-Lian Chen ◽  
Chang-Jun Wu

2018 ◽  
Vol 119 (1) ◽  
pp. 257-264 ◽  
Author(s):  
Timothy Joseph Breiner ◽  
Amanda Louise Ryan Ortiz ◽  
Rodger Kram

2013 ◽  
Vol 16 (4) ◽  
pp. 348-352 ◽  
Author(s):  
Alessandro Haupenthal ◽  
Heiliane de Brito Fontana ◽  
Caroline Ruschel ◽  
Daniela Pacheco dos Santos ◽  
Helio Roesler

1987 ◽  
Vol 3 (3) ◽  
pp. 189-206 ◽  
Author(s):  
Doris I. Miller ◽  
Mauno A. Nissinen

Ground reaction forces (GRF) elicited by nine male gymnasts during a running forward somersault were examined to investigate their characteristics in relation to the performance. Support averaged 135 ms with braking GRF dominating in the antero-posterior direction. Vertically, impact averaging 13.6 body weights (BW) was recorded followed by a second peak of 6.1 BW. The relative minimum in vertical GRF and lowest body position coincided temporally at 23% of support time; maximum knee flexion and minimum distance between the center of gravity (CG) and the support point occurred at 36 and 37%, respectively; and the second vertical GRF peak and maximum dorsiflexion were registered at 44%. The results suggested that, while vertical touchdown and last contact velocities of the CG could be approximated from GRF, eccentric ankle and knee extensor contraction continues beyond the relative minimum in the vertical GRF curve and is more closely related to the period before the CG reaches its minimum distance from the support point.


1996 ◽  
Vol 28 (Supplement) ◽  
pp. 46
Author(s):  
M. J. Webster ◽  
J. J. Helbig ◽  
L. D. Erdmann ◽  
C. S. McMillan ◽  
D. F. Mapes

2012 ◽  
Vol 20 (3-4) ◽  
pp. 274-285 ◽  
Author(s):  
William A. Braun ◽  
Sally Paulson

Author(s):  
Özge Drama ◽  
Alexander Badri-Spröwitz

Bipedal running is a difficult task to realize in robots, since the trunk is underactuated and control is limited by intermittent ground contacts. Stabilizing the trunk becomes even more challenging if the terrain is uneven and causes perturbations. One bio-inspired method to achieve postural stability is the virtual point (VP) control, which is able to generate natural motion. However, so far it has only been studied for level running. In this work, we investigate whether the VP control method can accommodate single step-down perturbations and downhill terrains. We provide guidelines on the model and controller parameterizations for handling varying terrain conditions. Next, we show that the VP method is able to stabilize single step-down perturbations up to 40 cm, and downhill grades up to 20–40° corresponding to running speeds of 2–5 ms−1. Our results show that the VP approach leads to asymmetrically bounded ground reaction forces for downhill running, unlike the commonly-used symmetric friction cone constraints. Overall, VP control is a promising candidate for terrain-adaptive running control of bipedal robots.


Author(s):  
Jurij Hladnik ◽  
Matej Supej ◽  
Janez Vodičar ◽  
Boris Jerman

This case study examines the impact of boot longitudinal flexural stiffness on the total external mechanical work of a skier’s centre of mass per distance travelled in the forward direction ([Formula: see text] EX (J/m)) and on running economy during skate roller-skiing under submaximal steady-state conditions. Moreover, it analyses time derivatives of total W EX, of W EX performed by the roller-skis and poles, respectively, and of the directly useful mechanical work (the sum of the work to overcome centre of mass’ gravity and rolling resistance) within a typical roller-skiing cycle. Multiple roller-skiing trials (G3 technique) were performed by one subject on an inclined treadmill with boots of soft, intermediate, and stiff flexural stiffness. The orientation and magnitude of the roller-ski and pole ground reaction forces, body kinematics, VO2, and lactic acid concentration were monitored. The stiff boots had 13.4% ( p < 0.01) lower [Formula: see text] EX compared to the intermediate boots, and 20.7% ( p < 0.001) lower [Formula: see text] EX compared to the soft boots. Regarding running economy, the soft boots had 2.2% ( p < 0.05) higher VO2 compared to the intermediate boots, but the same VO2 compared to the stiff boots. In conclusion, the soft boots had significantly higher [Formula: see text] EX and running economy, while stiff boots had significantly lower [Formula: see text] EX and intermediate boots significantly lower running economy. Moreover, [Formula: see text] EX appears to be a better indicator of the boot flexural stiffness impact on energy efficiency than running economy.


2006 ◽  
Vol 38 (Supplement) ◽  
pp. S387-S388
Author(s):  
Trevor C. Chen ◽  
Jui-Hung Tu ◽  
Priscilla M. Clarkson

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