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

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.

The exoskeleton expansion: improving walking and running economy

“…Seventeen publications presented improved human walking and/or running economy using an exoskeleton versus without using a device during preferred levelground conditions: twelve exoskeletons improved walking economy [11][12][13][25][26][27][28][29][30][31][32][33], four improved running economy [14,15,17,18], and one improved both walking and running economy [16] versus using no device ( Fig. 2).…”

“…Embedding 'smart mechanics' into passive exoskeletons provides an alternative to fully powered designs Laboratory-based exoskeletons are moving into the realworld through the use of small, transportable energy supplies [59] and/or by harvesting mechanical energy to power the device [60]. Despite these improvements, another way to circumnavigate the burden of lugging around bulky energy sources is by developing passive exoskeletons [13,17,18,31]. Passive exoskeletons have been able to assist the user by storing and subsequently returning mechanical energy to the user without injecting net positive mechanical work.…”

Passive-elastic knee-ankle exoskeleton reduces the metabolic cost of walking

“…The idea of creating mechanical devices to assist human movement and reduce metabolic cost has been around since the year 1890 [ 1 ]. During the twentieth century, many scientists have focused their efforts on creating mechanical devices that reduce the metabolic cost of human movement [ 2 ], and during the last decade, use of an unpowered passive-elastic exoskeleton has reduced the metabolic cost of walking compared to walking without an exoskeleton by improving efficiency (quotient of mechanical and metabolic power) [ 3 , 4 ].…”

A Kinematic Index for Estimation of Metabolic Rate Reduction in Running withI-RUN

“…Passive exoskeletons for metabolic rate reduction 1 in running and walking are popular in the research community because of their innovative design as well as the perspective of usability, low weight, and affordable cost 1,[3][4][5][6] . Nevertheless, as for the active ones, passive exoskeletons have not fulfilled the desired expectations yet.…”