Leg stiffness of older and younger individuals over a range of hopping frequencies

Hobara, Hiroaki; Kobayashi, Yoshiyuki; Yoshida, Eiichi; Mochimaru, Masaaki

doi:10.1016/j.jelekin.2015.02.004

Cited by 12 publications

(7 citation statements)

References 38 publications

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“…This study was limited by participant age skewing toward the younger end of the age range tested (68% under the average age of 30 yr., 26% > 30 yr.). However, it has been shown that young and elderly adults display similar spring-mass model-type behavior and limb stiffness across multiple hopping rates [13]. The vertical limb length control measured in this study is closely related to limb stiffness, and thus could be expected to be reasonably similar across age groups as well.…”

Section: Discussionmentioning

confidence: 53%

Movement variability response to change in the rate of hopping

Fietzer

Koyama

Kulig

2019

Acta Bioeng Biomech

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Movement variability is often considered undesirable, but growing evidence demonstrates positive aspects of variability. During unipedal hopping, control of limb stiffness and limb length are paramount. Purpose: The purpose of this study was to compare two methods of measuring movement variability that provide information at the task level, and their capacities to illuminate the neuromotor control system's response to change in hopping rate. Methods: The typical task-level movement variability measure of the standard deviation of vertical limb length was compared to uncontrolled manifold analysis. We examined the relationship between change scores in deviation from spring-mass model-type behavior and these two variability measures for the shift from typical (2.3 Hz) to slow (1.7 Hz) hopping. Results: The change scores for deviation from spring-mass model-type behavior and vertical limb length standard deviation demonstrated no correlation (p = 0.784, R = 0.051). In contrast, the change scores for deviation from spring-mass model-type behavior and the uncontrolled manifold analysis measure demonstrated a moderate correlation (p = 0.004, R = 0.502). Conclusions: Uncontrolled manifold analysis considers not just variability in the sense of error, but illustrates how the neuromotor control system distributes movement variability into performance-irrelevant and performance-destabilizing subspaces. As such, this type of analysis may be more effective at illuminating global control aspects of movement variability than the typical variability measure of limb length standard deviation.

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Section: Discussionmentioning

confidence: 53%

Movement variability response to change in the rate of hopping

Fietzer

Koyama

Kulig

2019

Acta Bioeng Biomech

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“…However, this two-segment leg model with a “J”-shape force-elongation curve cannot mimic adjustment of leg stiffness in fast animal locomotion. This is because limb stiffness is adapted to running speed; for example, Hobara et al [28] reveal through experiments that in humans leg stiffness is adjusted to different hopping frequencies, with the fact that there are two different force-elongation curves during compression and decompression. Hence, in order to adequately mimic limb compliant locomotion, these aspects should be taken into account in the design and implementation of robotic system.…”

Section: Discussionmentioning

confidence: 99%

Influence of “J”-Curve Spring Stiffness on Running Speeds of Segmented Legs during High-Speed Locomotion

Wang

Zhao

et al. 2016

Applied Bionics and Biomechanics

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Both the linear leg spring model and the two-segment leg model with constant spring stiffness have been broadly used as template models to investigate bouncing gaits for legged robots with compliant legs. In addition to these two models, the other stiffness leg spring models developed using inspiration from biological characteristic have the potential to improve high-speed running capacity of spring-legged robots. In this paper, we investigate the effects of “J”-curve spring stiffness inspired by biological materials on running speeds of segmented legs during high-speed locomotion. Mathematical formulation of the relationship between the virtual leg force and the virtual leg compression is established. When the SLIP model and the two-segment leg model with constant spring stiffness and with “J”-curve spring stiffness have the same dimensionless reference stiffness, the two-segment leg model with “J”-curve spring stiffness reveals that (1) both the largest tolerated range of running speeds and the tolerated maximum running speed are found and (2) at fast running speed from 25 to 40/92 m s−1 both the tolerated range of landing angle and the stability region are the largest. It is suggested that the two-segment leg model with “J”-curve spring stiffness is more advantageous for high-speed running compared with the SLIP model and with constant spring stiffness.

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“…Vertical displacement ( D V ) of the COM during ground contact. Calculated from numerical double integration in the time domain of the acceleration-time data, or equivalently, from the numerical integration in the time domain of the vertical velocity-time data [ 16 , 18 ]:

where:…”

Section: Methodsmentioning

confidence: 99%

Effects of Aging and Fitness on Hopping Biomechanics

Sánchez-Trigo

Zange

Sies

et al. 2022

IJERPH

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Physical exercise promotes healthy aging and is associated with greater functionality and quality of life. Muscle strength and power are established factors in the ability to perform daily tasks and live independently. Stiffness, for mechanical reasons, is another important constituent of running performance and locomotion. This study aims to analyze the impact of age and training status on one-legged hopping biomechanics and to evaluate whether age-related power decline can be reduced with regular physical exercise. Forty-three male subjects were recruited according to their suitability for one of four groups (young athletes, senior athletes, young controls and senior controls) according to their age (young between 21 and 35, vs. older between 59 and 75) and training status (competing athletes vs. non-physically active). The impact of age and training status on one-legged hopping biomechanics were evaluated using the two-way analysis of variance (ANOVA) method. Significant differences among groups were found for hopping height (p < 0.05), ground contact time (p < 0.05), peak ground reaction force (p < 0.05) and peak power (p < 0.01). No differences among groups were found in ground-phase vertical displacement and vertical stiffness (p > 0.05). Young athletes and older non-physically active people achieved the best and worst performance, respectively. Interestingly, there were not any differences found between young non-physically active people and senior athletes, suggesting that chronic training can contribute to partly offset effects that are normally associated with aging.

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Leg stiffness of older and younger individuals over a range of hopping frequencies

Cited by 12 publications

References 38 publications

Movement variability response to change in the rate of hopping

Movement variability response to change in the rate of hopping

Influence of “J”-Curve Spring Stiffness on Running Speeds of Segmented Legs during High-Speed Locomotion

Effects of Aging and Fitness on Hopping Biomechanics

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