Aging
Conditions
Keywords
Walking, Aging, Exoskeleton Device
Brief summary
The investigators seek to determine whether ankle exoskeletons can reduce metabolic energy expenditure during walking for users across the age-spectrum.
Detailed description
Older adults walk with greater metabolic rates than young adults. Growing evidence suggests that the greater older adult metabolic rates are related to the structural properties of their lower leg tissues. The tendons of the leg of older adults are more compliant than that of young adults. Accordingly, older adult leg tendons stretch more under a given load, such as during walking, causing their muscles to operate at shorter, less optimal lengths, and higher activity levels than the muscles of young adults - a less economical way to produces force. Thus, the investigators seek to examine whether wearing wearable robotic boots (i.e., ankle exoskeletons) could enable muscles to produce force more economically. By adding an exoskeleton in-parallel to the ankle, the investigators hypothesize that older adults will walk with lower whole-body metabolic rate than without the exoskeleton assistance. In this study, the investigators will have both young and older adult participants walk on a treadmill with a commercially available ankle exoskeleton set in multiple assistance modes. During these trials, the investigators will measure the metabolic cost of walking in young and older adults and also take many physiological and biomechanical measurements to help assess how exoskeletons work to reduce walking effort.
Interventions
DEVICEAnkle Exoskeleton Assistance
The investigators will use ankle-exoskeletons to modulate the amount of mechanical power generated by the user's ankle joint. That is, participants will walk in a robotic device that either (a) adds a spring or (b) a motor in parallel with their calf muscles to help them generate a stronger propulsive push-off that could reduce the effort of walking.
Sponsors
National Institute on Aging (NIA)
Georgia Institute of Technology
Study design
Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
NONE
Intervention model description
All participants will perform the same trials/sessions to complete the entire protocol. After each participant has performed all trials for this study, the investigators will analyze the data of this repeated-measures design.
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* Subjects must be able to walk for 60 minutes in a 90-minute time frame. * Subjects are apparently free of cardiovascular, metabolic, and renal disease, which includes no signs or symptoms suggestive of cardiovascular, metabolic or renal disease. * Subjects have no current musculoskeletal injury. * Subjects need to be either 18-45 or 65+ years old. These criteria meet the American College of Sports Medicine's 2015 guidelines for participant health screening prior to joining a moderate or moderate-to-vigorous exercise protocol. (Riebe et al., 2015).
Exclusion criteria
* Have dementia or an inability to give informed consent * Have a musculoskeletal injury or feel pain while walking * Have a history of dizziness and/or balance problems * Have cardiovascular, heart, metabolic, or renal disease, or respiratory problems * Smoke cigarettes * Asthma * Feel pain or discomfort in the chest, neck, jaw, arms during rest or exercise * Have orthopnea or paroxysmal nocturnal dyspnea * Have ankle edema * Have palpitations or tachycardia * Have a heart murmur * Have had a heart attack * Have diabetes * Have a pace maker * Have unusual shortness of breath with usual activities * Are \<18 or 46-64 years of age * Do not speak or understand English
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Net Metabolic Rate (Watts/kg) | 3rd session, up to 2 weeks | The rate of metabolic energy that participants expend during a short walking bout in each of the experimental conditions. |
Countries
United States
Participant flow
Recruitment details
Participants were enrolled and participated in the study from 2/4/2020 to 5/23/2023.
Participants by arm
| Arm | Count |
|---|---|
| Young Adult Exoskeleton Users Study participants who are 18-45 year old. | 10 |
| Older Adult Exoskeleton Users Study participants who are \>65 years old | 6 |
| Total | 16 |
Baseline characteristics
| Characteristic | Young Adult Exoskeleton Users | Older Adult Exoskeleton Users | Total |
|---|---|---|---|
| Age, Categorical <=18 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical >=65 years | 0 Participants | 6 Participants | 6 Participants |
| Age, Categorical Between 18 and 65 years | 10 Participants | 0 Participants | 10 Participants |
| Race and Ethnicity Not Collected | — | — | 0 Participants |
| Sex: Female, Male Female | 3 Participants | 5 Participants | 8 Participants |
| Sex: Female, Male Male | 7 Participants | 1 Participants | 8 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 10 | 0 / 6 |
| other Total, other adverse events | 0 / 10 | 0 / 6 |
| serious Total, serious adverse events | 0 / 10 | 0 / 6 |
Outcome results
Primary
Net Metabolic Rate (Watts/kg)
The rate of metabolic energy that participants expend during a short walking bout in each of the experimental conditions.
Time frame: 3rd session, up to 2 weeks
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Young Adult Exoskeleton Users | Net Metabolic Rate (Watts/kg) | No Exoskeleton | 3.30 watts/kg | Standard Deviation 0.66 |
| Young Adult Exoskeleton Users | Net Metabolic Rate (Watts/kg) | No Torque | 3.86 watts/kg | Standard Deviation 0.62 |
| Young Adult Exoskeleton Users | Net Metabolic Rate (Watts/kg) | Spring-like Torque | 3.72 watts/kg | Standard Deviation 0.78 |
| Young Adult Exoskeleton Users | Net Metabolic Rate (Watts/kg) | Motor-like Low Torque | 3.51 watts/kg | Standard Deviation 0.83 |
| Young Adult Exoskeleton Users | Net Metabolic Rate (Watts/kg) | Motor-like Medium Torque | 3.13 watts/kg | Standard Deviation 0.7 |
| Young Adult Exoskeleton Users | Net Metabolic Rate (Watts/kg) | Motor-like High Torque | 3.24 watts/kg | Standard Deviation 0.65 |
| Older Adult Exoskeleton Users | Net Metabolic Rate (Watts/kg) | Motor-like Medium Torque | 3.46 watts/kg | Standard Deviation 0.56 |
| Older Adult Exoskeleton Users | Net Metabolic Rate (Watts/kg) | No Exoskeleton | 3.47 watts/kg | Standard Deviation 0.31 |
| Older Adult Exoskeleton Users | Net Metabolic Rate (Watts/kg) | Motor-like Low Torque | 3.68 watts/kg | Standard Deviation 0.65 |
| Older Adult Exoskeleton Users | Net Metabolic Rate (Watts/kg) | No Torque | 4.18 watts/kg | Standard Deviation 0.62 |
| Older Adult Exoskeleton Users | Net Metabolic Rate (Watts/kg) | Motor-like High Torque | 3.20 watts/kg | Standard Deviation 0.52 |
| Older Adult Exoskeleton Users | Net Metabolic Rate (Watts/kg) | Spring-like Torque | 4.34 watts/kg | Standard Deviation 0.57 |
Comparison: H1. Bilateral ankle exoskeletons that provide 'motor-like' assistance will result in lower net metabolic power than those providing 'spring-like' assistance for young adults.~H2. Bilateral ankle exoskeletons that provide 'motor-like' assistance will result in lower net metabolic power than those providing 'spring-like' assistance for older adults.p-value: <0.001ANOVA