Adaptation to walking with an exoskeleton that assists ankle extension

Enhancing performance during inclined loaded walking with a powered ankle–foot exoskeleton

“…1B). The goal of our exoskeleton is to add plantarflexion power to the ankle during push-off (Galle et al 2013a(Galle et al , 2013bMalcolm et al 2013). The pneumatic muscles can be turned on and turned off at specific time intervals based on footswitch signals and are triggered with a computer program (Labview, National Instruments, Austin, TX).…”

“…While most research is focused on technical enhancements, a quantitative evaluation of the effectiveness is often missing (Dollar and Herr 2008). The metabolic energy expenditure, often calculated as metabolic power (W•kg -1 ) based on oxygen consumption and carbon dioxide using a standard equation (Brockway 1987) and body weight normalization, is a key value in the evaluation of several exoskeleton devices (Galle et al 2013a;Malcolm et al 2013;Mooney et al 2014;Norris et al 2007a;Sawicki and Ferris 2008, 2009a, 2009bWehner et al 2013). Regardless of the functional goal of the device, reducing the metabolic power will improve the usability of the exoskeleton (Ferris et al 2007) and can therefore be considered a prime outcome when evaluating exoskeleton effectiveness, that can even be used to drive kinematic behavior with exoskeletons (Collins and Jackson 2013).…”

“…Walking with powered exoskeletons with pneumatic muscles that assist plantarflexion during push-off results in reductions in metabolic power of 10 to 17% compared to walking with an unpowered exoskeleton (without plantarflexion assistance) (Galle et al 2013a;Malcolm et al 2013;Norris et al 2007a; Sawicki and Ferris 2008, 2009a, 2009b. Despite the increased weight of the device, Malcolm et al (2013) were the first to report a 6% reduction in metabolic power for powered exoskeleton walking compared to walking with normal shoes if the actuation timing of the exoskeleton was optimal.…”

“…However, we are not aware of any succesfull attempts in increasing walking performance during maximal exercise intensities as current research is mainly focused on submaximal intensities (Galle et al 2013a;Malcolm et al 2013;Mooney et al 2014;Norris et al 2007a;Sawicki and Ferris 2008, 2009a, 2009b. Studying higher intensities is also useful for applications in specific populations (e.g.…”

“…The aim of our study is to quantify the walking performance during a maximal incremental exercise with a simple powered ankle-foot exoskeleton with plantarflexion assistance (Galle et al 2013a;Malcolm et al 2013). Therefore, an incremental walking exercise test similar to the weighted walking test (Klimek and Klimek 2007) will be used and the walking performance during this test will be expressed as the weight that subjects are carrying at volitional termination of the test.…”