scholarly journals A Single Assistive Profile Applied by a Passive Hip Flexion Device Can Reduce the Energy Cost of Walking in Older Adults

2021 ◽  
Vol 11 (6) ◽  
pp. 2851
Author(s):  
Fausto Antonio Panizzolo ◽  
Eugenio Annese ◽  
Antonio Paoli ◽  
Giuseppe Marcolin
Keyword(s):  
Older Adults ◽  
Energy Cost ◽  
Metabolic Cost ◽  
Metabolic Energy ◽  
Assistive Device ◽  
Spatiotemporal Parameters ◽  
Negative Effect ◽  
Low Torque ◽  
Hip Flexion ◽  
Energy Cost Of Walking

Difficulty walking in older adults affects their independence and ability to execute daily tasks in an autonomous way, which can result in a negative effect to their health status and risk of morbidity. Very often, reduced walking speed in older adults is caused by an elevated metabolic energy cost. Passive exoskeletons have been shown to offer a promising solution for lowering the energy cost of walking, and their simplicity could favor their use in real world settings. The goal of this study was to assess if a constant and consistent low torque applied by means of a passive exoskeleton to the hip flexors during walking could provide higher and more consistent metabolic cost reduction than previously achieved. Eight older adults walked on a treadmill at a constant speed of 1.1 m/s with and without the hip assistive device. Metabolic power and spatiotemporal parameters were measured during walking in these two conditions of testing. The hip assistive device was able to apply a low torque which initiates its assistive effect at mid-stance. This reduced the metabolic cost of walking across all the participants with respect to free walking (−4.2 ± 1.9%; p = 0.002). There were no differences in the spatiotemporal parameters reported. This study strengthened the evidence that passive assistive devices can be a valuable tool to reduce metabolic cost of walking in older adults. These findings highlighted the importance of investigating torque profiles to improve the performance provided by a hip assistive device. The simplicity and usability of a system of this kind can make it a suitable candidate for improving older adults’ independence.

scholarly journals Reducing the metabolic energy of walking and running using an unpowered hip exoskeleton

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Tiancheng Zhou ◽  
Caihua Xiong ◽  
Juanjuan Zhang ◽  
Di Hu ◽  
Wenbin Chen ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Design Method ◽  
Metabolic Cost ◽  
Metabolic Energy ◽  
Spring Stiffness ◽  
Spatiotemporal Parameters ◽  
The Common ◽  
Hip Flexion ◽  
Optimal Stiffness ◽  
Insight Into

Abstract Background Walking and running are the most common means of locomotion in human daily life. People have made advances in developing separate exoskeletons to reduce the metabolic rate of walking or running. However, the combined requirements of overcoming the fundamental biomechanical differences between the two gaits and minimizing the metabolic penalty of the exoskeleton mass make it challenging to develop an exoskeleton that can reduce the metabolic energy during both gaits. Here we show that the metabolic energy of both walking and running can be reduced by regulating the metabolic energy of hip flexion during the common energy consumption period of the two gaits using an unpowered hip exoskeleton. Methods We analyzed the metabolic rates, muscle activities and spatiotemporal parameters of 9 healthy subjects (mean ± s.t.d; 24.9 ± 3.7 years, 66.9 ± 8.7 kg, 1.76 ± 0.05 m) walking on a treadmill at a speed of 1.5 m s−1 and running at a speed of 2.5 m s−1 with different spring stiffnesses. After obtaining the optimal spring stiffness, we recruited the participants to walk and run with the assistance from a spring with optimal stiffness at different speeds to demonstrate the generality of the proposed approach. Results We found that the common optimal exoskeleton spring stiffness for walking and running was 83 Nm Rad−1, corresponding to 7.2% ± 1.2% (mean ± s.e.m, paired t-test p < 0.01) and 6.8% ± 1.0% (p < 0.01) metabolic reductions compared to walking and running without exoskeleton. The metabolic energy within the tested speed range can be reduced with the assistance except for low-speed walking (1.0 m s−1). Participants showed different changes in muscle activities with the assistance of the proposed exoskeleton. Conclusions This paper first demonstrates that the metabolic cost of walking and running can be reduced using an unpowered hip exoskeleton to regulate the metabolic energy of hip flexion. The design method based on analyzing the common energy consumption characteristics between gaits may inspire future exoskeletons that assist multiple gaits. The results of different changes in muscle activities provide new insight into human response to the same assistive principle for different gaits (walking and running).

scholarly journals Reducing the energy cost of walking in older adults using a passive hip flexion device

2019 ◽  
Vol 16 (1) ◽  
Author(s):  
Fausto A. Panizzolo ◽  
Chiara Bolgiani ◽  
Laura Di Liddo ◽  
Eugenio Annese ◽  
Giuseppe Marcolin
Keyword(s):  
Older Adults ◽  
Energy Cost ◽  
Perceived Exertion ◽  
Optical Measurement ◽  
Assistive Device ◽  
Older Individuals ◽  
Metabolic Power ◽  
Temporal Parameters ◽  
Spatio Temporal ◽  
Energy Cost Of Walking

Abstract Background Elevated energy cost is a hallmark feature of gait in older adults. As such, older adults display a general avoidance of walking which contributes to declining health status and risk of morbidity. Exoskeletons offer a great potential for lowering the energy cost of walking, however their complexity and cost often limit their use. To overcome some of these issues, in the present work we propose a passive wearable assistive device, namely Exoband, that applies a torque to the hip flexors thus reducing the net metabolic power of wearers. Methods Nine participants (age: 62.1 ± 5.6 yr; height: 1.71 ± 0.05 m; weight: 76.3 ± 11.9 kg) walked on a treadmill at a speed of 1.1 m/s with and without the Exoband. Metabolic power was measured by indirect calorimetry and spatio-temporal parameters measured using an optical measurement system. Heart rate and ratings of perceived exertion were recorded during data collection to monitor relative intensity of the walking trials. Results The Exoband was able to provide a consistent torque (~ 0.03–0.05 Nm/kg of peak torque) to the wearers. When walking with the Exoband, participants displayed a lower net metabolic power with respect to free walking (− 3.3 ± 3.0%; p = 0.02). There were no differences in spatio-temporal parameters or relative intensities when walking with or without the Exoband. Conclusions This study demonstrated that it is possible to reduce metabolic power during walking in older adults with the assistance of a passive device that applies a torque to the hip joint. Wearable, lightweight and low-cost devices such as the Exoband have the potential to make walking less metabolically demanding for older individuals.

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.

scholarly journals Elastic energy savings and active energy cost in a simple model of running

2021 ◽  
Vol 17 (11) ◽  
pp. e1009608
Author(s):  
Ryan T. Schroeder ◽  
Arthur D. Kuo
Keyword(s):  
Elastic Energy ◽  
Energy Cost ◽  
Energy Savings ◽  
Mechanical Energy ◽  
Metabolic Cost ◽  
The Body ◽  
Metabolic Energy ◽  
Energetic Cost ◽  
Mass Model ◽  
Human Running

The energetic economy of running benefits from tendon and other tissues that store and return elastic energy, thus saving muscles from costly mechanical work. The classic “Spring-mass” computational model successfully explains the forces, displacements and mechanical power of running, as the outcome of dynamical interactions between the body center of mass and a purely elastic spring for the leg. However, the Spring-mass model does not include active muscles and cannot explain the metabolic energy cost of running, whether on level ground or on a slope. Here we add explicit actuation and dissipation to the Spring-mass model, and show how they explain substantial active (and thus costly) work during human running, and much of the associated energetic cost. Dissipation is modeled as modest energy losses (5% of total mechanical energy for running at 3 m s-1) from hysteresis and foot-ground collisions, that must be restored by active work each step. Even with substantial elastic energy return (59% of positive work, comparable to empirical observations), the active work could account for most of the metabolic cost of human running (about 68%, assuming human-like muscle efficiency). We also introduce a previously unappreciated energetic cost for rapid production of force, that helps explain the relatively smooth ground reaction forces of running, and why muscles might also actively perform negative work. With both work and rapid force costs, the model reproduces the energetics of human running at a range of speeds on level ground and on slopes. Although elastic return is key to energy savings, there are still losses that require restorative muscle work, which can cost substantial energy during running.

The Association of Mobility Determinants and Life Space Among Older Adults

2021 ◽  
Author(s):  
Pamela M Dunlap ◽  
Andrea L Rosso ◽  
Xiaonan Zhu ◽  
Brooke N Klatt ◽  
Jennifer S Brach
Keyword(s):  
Older Adults ◽  
Lower Extremity ◽  
Energy Cost ◽  
Community Dwelling ◽  
Walk Test ◽  
Personal Factors ◽  
Linear Regression Models ◽  
Life Space ◽  
Mobility Disability ◽  
Energy Cost Of Walking

Abstract Background It is important to understand the factors associated with life space mobility so that mobility disability can be prevented/treated. The purpose of this study was to identify the association between mobility determinants and life space among older adults. Methods This study was a cross-sectional analysis of 249 community-dwelling older adults (mean age=77.4 years, 65.5% female, 88% white) who were recruited for a randomized, controlled, clinical intervention trial. Associations between cognitive, physical, psychosocial, financial, and environmental mobility determinants and the Life Space Assessment (LSA) at baseline were determined using Spearman’s correlation coefficients and one-way analysis of variance. Multivariate analysis was performed using multivariable linear regression models. Results The mean LSA score for the sample was 75.3 (SD=17.8). Personal factors (age, gender, education, comorbidities), cognitive (Trail Making Test A and B), physical (gait speed, lower extremity power, Six Minute Walk Test, Figure of 8 Walk Test, tandem stance, energy cost of walking, and Late Life Function and Disability Function Scale), psychosocial (Modified Gait Efficacy Scale), and financial (neighborhood socio-economic status) domains of mobility were significantly associated with LSA score. In the final regression model, age (β=-0.43), lower extremity power (β=0.03), gait efficacy (β=0.19), and energy cost of walking (β=-57.41) were associated with life space (R 2=0.238). Conclusions Younger age, greater lower extremity power, more confidence in walking, and lower energy cost of walking were associated with greater life space. Clinicians treating individuals with mobility disability should consider personal, physical, and psychosocial factors assessing barriers to life space mobility.

scholarly journals Cycling efficiency and energy cost of walking in young and older adults

2018 ◽  
Vol 124 (2) ◽  
pp. 414-420 ◽  
Author(s):  
Glenn A. Gaesser ◽  
Wesley J. Tucker ◽  
Brandon J. Sawyer ◽  
Dharini M. Bhammar ◽  
Siddhartha S. Angadi
Keyword(s):  
Older Adults ◽  
Individual Variation ◽  
Energy Cost ◽  
Intraclass Correlation ◽  
Age Groups ◽  
Net Energy ◽  
Age Group ◽  
Cycling Efficiency ◽  
Considerable Individual Variation ◽  
Energy Cost Of Walking

To determine whether age affects cycling efficiency and the energy cost of walking (Cw), 190 healthy adults, ages 18–81 yr, cycled on an ergometer at 50 W and walked on a treadmill at 1.34 m/s. Ventilation and gas exchange at rest and during exercise were used to calculate net Cw and net efficiency of cycling. Compared with the 18–40 yr age group (2.17 ± 0.33 J·kg−1·m−1), net Cw was not different in the 60–64 yr (2.20 ± 0.40 J·kg−1·m−1) and 65–69 yr (2.20 ± 0.28 J·kg−1·m−1) age groups, but was significantly ( P < 0.03) higher in the ≥70 yr (2.37 ± 0.33 J·kg−1·m−1) age group. For subjects >60 yr, net Cw was significantly correlated with age ( R2 = 0.123; P = 0.002). Cycling net efficiency was not different between 18–40 yr (23.5 ± 2.9%), 60–64 yr (24.5 ± 3.6%), 65–69 yr (23.3 ± 3.6%) and ≥70 yr (24.7 ± 2.7%) age groups. Repeat tests on a subset of subjects (walking, n = 43; cycling, n = 37) demonstrated high test-retest reliability [intraclass correlation coefficients (ICC), 0.74–0.86] for all energy outcome measures except cycling net energy expenditure (ICC = 0.54) and net efficiency (ICC = 0.50). Coefficients of variation for all variables ranged from 3.1 to 7.7%. Considerable individual variation in Cw and efficiency was evident, with a ~2-fold difference between the least and most economical/efficient subjects. We conclude that, between 18 and 81 yr, net Cw was only higher for ages ≥70 yr, and that cycling net efficiency was not different across age groups. NEW & NOTEWORTHY This study illustrates that the higher energy cost of walking in older adults is only evident for ages ≥70 yr. For older adults ages 60–69 yr, the energy cost of walking is similar to that of young adults. Cycling efficiency, by contrast, is not different across age groups. Considerable individual variation (∼2-fold) in cycling efficiency and energy cost of walking is observed in young and older adults.

scholarly journals Correlation between cardiopulmonary metabolic energy cost and lower-limb muscle activity during inclined treadmill gait in older adults

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jihye Kim ◽  
Hwang-Jae Lee ◽  
Su-Hyun Lee ◽  
Jungsoo Lee ◽  
Won Hyuk Chang ◽  
...  
Keyword(s):  
Older Adults ◽  
Lower Limb ◽  
Muscle Activity ◽  
Energy Cost ◽  
Stance Phase ◽  
Treadmill Walking ◽  
Metabolic Energy ◽  
Lower Limb Muscle ◽  
Limb Muscle ◽  
Increased Activity

Abstract Background Inclined walking requires more cardiopulmonary metabolic energy and muscle strength than flat-level walking. This study sought to investigate changes in lower-limb muscle activity and cardiopulmonary metabolic energy cost during treadmill walking with different inclination grades and to discern any correlation between these two measures in older adults. Methods Twenty-four healthy older adults (n = 11 males; mean age: 75.3 ± 4.0 years) participated. All participants walked on a treadmill that was randomly inclined at 0% (condition 1), 10% (condition 2), and 16% (condition 3) for five minutes each. Simultaneous measurements of lower-limb muscle activity and cardiopulmonary metabolic energy cost during inclined treadmill walking were collected. Measured muscles included the rectus abdominis (RA), erector spinae (ES), rectus femoris (RF), biceps femoris (BF), vastus medialis (VM), tibialis anterior (TA), medial head of the gastrocnemius (GCM), and soleus (SOL) muscles on the right side. Results As compared with 0% inclined treadmill gait, the 10% inclined treadmill gait increased the net cardiopulmonary metabolic energy cost by 22.9%, while the 16% inclined treadmill gait increased the net cardiopulmonary metabolic energy cost by 44.2%. In the stance phase, as the slope increased, activity was significantly increased in the RA, RF, VM, BF, GCM, and SOL muscles. In the swing phase, As the slope increased activity was significantly increased in the RA, RF, VM, BF, and TA muscles. SOL muscle activity was most relevant to the change in cardiopulmonary metabolic energy cost in the stance phase of inclined treadmill walking. The relationship between the increase in cardiopulmonary metabolic energy cost and changes in muscle activity was also significant in the VM, GCM, and RF. Conclusion This study demonstrated that changes in SOL, VM, GCM, and RA muscle activity had a significant relationship with cardiopulmonary metabolic energy cost increment during inclined treadmill walking. These results can be used as basic data for various gait-training programs and as an indicator in the development of assistive algorithms of wearable walking robots for older adults. Trial registration Clinical trials registration information: ClinicalTrials.gov Identifier: NCT04614857 (05/11/2020).

Reducing the metabolic energy of walking and running using an unpowered hip exoskeleton

2020 ◽  
Author(s):  
Tiancheng Zhou ◽  
Caihua Xiong ◽  
Juanjuan Zhang ◽  
Di Hu ◽  
Wenbin Chen ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Design Method ◽  
Metabolic Cost ◽  
Metabolic Energy ◽  
Human Response ◽  
Speed Range ◽  
The Common ◽  
Spatio Temporal ◽  
Hip Flexion ◽  
Optimal Stiffness

Abstract Background: Walking and running are the most common means of locomotion in human daily life. People have made advances in developing separate exoskeletons to reduce metabolic rate of walking or running. However, the combined requirements of overcoming fundamental biomechanical differences between the two gaits and minimizing the metabolic penalty of exoskeleton mass make it challenging to develop an exoskeleton that can reduce the metabolic energy for both gaits. Here we show that the metabolic energy of both walking and running can be reduced by regulating the metabolic energy of hip flexion during the common energy consumption period of the two gaits using an unpowered hip exoskeleton. Methods: We analyzed metabolic rates, muscle activities and spatio-temporal parameters from 9 healthy subjects (mean s.t.d; 24.9 ± 3.7 years, 66.9 ± 8.7 kg, 1.76 ± 0.05 m) walking on a treadmill at the speed of 1.5 m×s -1 and running at speed of 2.5 m×s -1 with different spring stiffnesses. After obtaining the optimal spring stiffness, we recruited the participants to walk and run with the optimal stiffness spring at different speeds to demonstrate the generality of the proposed approach. Results: We found that the optimal exoskeleton spring stiffnesses for walking and running were 140 N×m Rad -1 and 210 N×m Rad -1 respectively, corresponding to 8.2% ± 1.5% (mean ± s.e.m, two-sided paired t-test: p < 0.01) and 9.1% ± 1.3% ( p < 0.01) metabolic reductions compared to walking/running without exoskeleton. The metabolic energy within tested speed range can be reduced with the assistance except for low speed walking (1.0 m s -1 ). Participants showed different changes in muscle activities with the assistance of proposed exoskeleton. Conclusions: This paper first demonstrated that metabolic cost of walking and running can be reduced using an unpowered hip exoskeleton to regulate metabolic energy of hip flexion. The design method based on analyzing the common energy consumption characteristics between gaits may inspire future exoskeletons that assist multiple gaits. The results of different changes in muscle activities provided a new insight of human response to the same assistive principle in different gaits (walking and running).

scholarly journals The effects of ankle stiffness on mechanics and energetics of walking with added loads: a prosthetic emulator study

2019 ◽  
Vol 16 (1) ◽  
Author(s):  
Erica A. Hedrick ◽  
Philippe Malcolm ◽  
Jason M. Wilken ◽  
Kota Z. Takahashi
Keyword(s):  
Energy Cost ◽  
Load Condition ◽  
Metabolic Cost ◽  
Load Carriage ◽  
Metabolic Energy ◽  
Additional Load ◽  
Ankle Stiffness ◽  
Human Ankle ◽  
Positive Work ◽  
Load Conditions

Abstract Background The human ankle joint has an influential role in the regulation of the mechanics and energetics of gait. The human ankle can modulate its joint ‘quasi-stiffness’ (ratio of plantarflexion moment to dorsiflexion displacement) in response to various locomotor tasks (e.g., load carriage). However, the direct effect of ankle stiffness on metabolic energy cost during various tasks is not fully understood. The purpose of this study was to determine how net metabolic energy cost was affected by ankle stiffness while walking under different force demands (i.e., with and without additional load). Methods Individuals simulated an amputation by using an immobilizer boot with a robotic ankle-foot prosthesis emulator. The prosthetic emulator was controlled to follow five ankle stiffness conditions, based on literature values of human ankle quasi-stiffness. Individuals walked with these five ankle stiffness settings, with and without carrying additional load of approximately 30% of body mass (i.e., ten total trials). Results Within the range of stiffness we tested, the highest stiffness minimized metabolic cost for both load conditions, including a ~ 3% decrease in metabolic cost for an increase in stiffness of about 0.0480 Nm/deg/kg during normal (no load) walking. Furthermore, the highest stiffness produced the least amount of prosthetic ankle-foot positive work, with a difference of ~ 0.04 J/kg from the highest to lowest stiffness condition. Ipsilateral hip positive work did not significantly change across the no load condition but was minimized at the highest stiffness for the additional load conditions. For the additional load conditions, the hip work followed a similar trend as the metabolic cost, suggesting that reducing positive hip work can lower metabolic cost. Conclusion While ankle stiffness affected the metabolic cost for both load conditions, we found no significant interaction effect between stiffness and load. This may suggest that the importance of the human ankle’s ability to change stiffness during different load carrying tasks may not be driven to minimize metabolic cost. A prosthetic design that can modulate ankle stiffness when transitioning from one locomotor task to another could be valuable, but its importance likely involves factors beyond optimizing metabolic cost.

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