Effect of augmented plantarflexion power on preferred walking speed and economy in young and older adults

Norris, James A.; Granata, Kevin P.; Mitros, Melanie; Byrne, Erica M.; Marsh, Anthony P.

doi:10.1016/j.gaitpost.2006.07.002

Cited by 92 publications

(109 citation statements)

References 35 publications

(37 reference statements)

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“…When considering aging, it is known that force production capacity declines and movements become slower (Candow and Chilibeck, Lanza et al 2003;Norris et al 2007). Part of these changes are due to the aging process itself and part is due to a decrease in physical activity level, especially exercises that include rapid force production (Candow and Chilibeck.…”

Section: Why Should the Elderly Perform Hopping Training?mentioning

confidence: 99%

“…Generally, the movements in elderly can be characterized as weak (Candow and Chilibeck. 2005;Norris et al 2007), slow (Lanza et al 2003;Norris et al 2007) and less economical (Malatesta et al 2003;Mian et al 2006) when compared to those of the young. Part of these changes are due to the aging process itself (Pearson et al 2002) but may be partly explained by the decrease in physical activity level that typically occurs with aging (Hunter et al 2000), especially high intensity exercises that require rapid force production (Candow and Chilibeck 2005;Morse et al 2004).…”

Section: Introductionmentioning

confidence: 95%

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Neuromuscular mechanics and hopping training in elderly

et al. 2014

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Phone +358-40-8053384 merja.hoffren@jyu.fi 2 ABSTRACT Purpose: The present study examined the effects of repetitive hopping training on muscle activation profiles and fascicletendon interaction in the elderly.Methods: 20 physically active elderly men were randomly assigned for training (TG) and control groups (CG). TG performed supervised bilateral short contact hopping training with progressively increasing training volume. Measurements were performed before the training period (BEF) as well as after 2 weeks (2W) and 11 weeks (11W) of training. During measurements the gastrocnemius medialis -muscle (GaM) fascicle and its outer Achilles tendon length changes during hopping were examined by ultrasonography together with electromyographic (EMG) activities of calf muscles, kinematics, and kinetics.Results: At 2W the ankle joint stiffness was increased by 21.0 ± 19.3 % and contact time decreased by 9.4 ± 7.8 % in TG.Thereafter, from 2-11W the jumping height increased 56.2 ± 18.1 % in TG. Simultaneously tendon forces increased 24.3 ± 19.0 % but tendon stiffness did not change. GaM fascicles shifted to shorter operating lengths after training without any changes in their length modifications during the contact phase of hopping. Normalized EMG amplitudes during hopping did not change with training.Conclusions: The present study shows that 11 weeks of hopping training improves the performance of physically active elderly men. This improvement is achieved with shorter GaM operating lengths and therefore increased fascicle stiffness and improved tendon utilization after training. Based on these results hopping training could be recommended for healthy fit elderly to retain and improve rapid force production capacity.

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Section: Why Should the Elderly Perform Hopping Training?mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

Neuromuscular mechanics and hopping training in elderly

et al. 2014

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“…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).…”

Section: Introductionmentioning

confidence: 99%

“…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.…”

Section: Introductionmentioning

confidence: 99%

“…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.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2014

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PURPOSE. A simple ankle-foot exoskeleton that assists plantarflexion during push-off can reduce the metabolic power during walking. This suggests that walking performance during a maximal incremental exercise could be improved with an exoskeleton if the exoskeleton is still efficient during maximal exercise intensities. Therefore, we quantified the walking performance during a maximal incremental exercise test with a powered and unpowered exoskeleton: uphill walking with progressively higher weights.METHODS. Nine female subjects performed two incremental exercise tests with an exoskeleton: one day with (powered condition) and another day without (unpowered condition) plantarflexion assistance.Subjects walked on an inclined treadmill (15%) at 5 km•h -1 and 5% of body weight was added every 3 min until exhaustion.RESULTS. At volitional termination no significant differences were found between the powered and unpowered condition for blood lactate concentration (respectively 7.93±2.49; 8.14±2.24mmol•L -1 ), heart rate (respectively 190.00±6.50; 191.78±6.50bpm), Borg score (respectively 18.57±0.79; 18.93±0.73) and 2 peak (respectively 40.55±2.78; 40.55±3.05ml•min -1 •kg -1 ). Thus, subjects were able to reach the same (near) maximal effort in both conditions. However, subjects continued the exercise test longer in the powered condition and carried 7.07±3.34kg more weight because of the assistance of the exoskeleton.

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