Author ORCID Identifier
0000-0002-7841-5471
Advisor Information
Dr. Kota Takahashi
Location
Room 225
Presentation Type
Oral Presentation
Start Date
1-3-2019 2:15 PM
End Date
1-3-2019 3:15 PM
Abstract
The ankle structures play a key role in body support, forward propulsion and leg swing. One important property of the human ankle is its ‘quasi-stiffness’, or resistance to angular motion. The ankle joint stiffness can play a role in aiding the lower leg as its rocks over the foot. Human biological ankle stiffness changes in response to changes in the mechanical demands of walking (e.g. added load or changes in speed), using active muscle contractions. However, the role of ankle stiffness in regulating metabolic energy across walking conditions is unknown. Therefore, the purpose of this study is to determine how metabolic energy cost is affected by ankle joint stiffness while walking with different mechanical demands (e.g. carrying additional loads). Participants wore an immobilizer boot with a distally-attached unilateral ankle-foot prosthesis emulator that simulated various stiffnesses of perfectly elastic springs. Each individual walked for 6 minutes at 2 different loading conditions (with and without 30% body mass), and 5 stiffness conditions: the typical human ankle stiffness, and ±20% and ±10% of that value. The energy consumption increased when carrying additional load (p=0.011) and the trend was for higher stiffness to provide greater metabolic benefit with added load (p=0.15). These preliminary data suggest that the ability to vary ankle stiffness while walking may be important when seeking to minimize metabolic power in walking tasks of varied demand (such as carrying additional loads). These results can also be applicable to the development of novel designs for assistive devices that emulate these functions.
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Included in
How Prosthetic Ankle Stiffness & Load Carriage Affect Metabolic Energy Expenditure During Walking
Room 225
The ankle structures play a key role in body support, forward propulsion and leg swing. One important property of the human ankle is its ‘quasi-stiffness’, or resistance to angular motion. The ankle joint stiffness can play a role in aiding the lower leg as its rocks over the foot. Human biological ankle stiffness changes in response to changes in the mechanical demands of walking (e.g. added load or changes in speed), using active muscle contractions. However, the role of ankle stiffness in regulating metabolic energy across walking conditions is unknown. Therefore, the purpose of this study is to determine how metabolic energy cost is affected by ankle joint stiffness while walking with different mechanical demands (e.g. carrying additional loads). Participants wore an immobilizer boot with a distally-attached unilateral ankle-foot prosthesis emulator that simulated various stiffnesses of perfectly elastic springs. Each individual walked for 6 minutes at 2 different loading conditions (with and without 30% body mass), and 5 stiffness conditions: the typical human ankle stiffness, and ±20% and ±10% of that value. The energy consumption increased when carrying additional load (p=0.011) and the trend was for higher stiffness to provide greater metabolic benefit with added load (p=0.15). These preliminary data suggest that the ability to vary ankle stiffness while walking may be important when seeking to minimize metabolic power in walking tasks of varied demand (such as carrying additional loads). These results can also be applicable to the development of novel designs for assistive devices that emulate these functions.