Comparison of mechanical energy expenditure of joint moments and muscle forces during human locomotion

Prilutsky, Boris I.; Petrova, Ludmila N.; Raitsin, Leonid M.

doi:10.1016/0021-9290(95)00083-6

Cited by 55 publications

(25 citation statements)

References 28 publications

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“…In general, biarticular muscles act to overestimate musculotendon work from joint work (e.g. Prilutsky et al, 1996), because the muscle joint power is separately time integrated to compute joint work (e.g. see Fig.…”

Section: Discussionmentioning

confidence: 99%

The relationships between muscle, external, internal and joint mechanical work during normal walking

Sasaki

Neptune

Kautz

2009

Journal of Experimental Biology

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SUMMARYMuscle mechanical work is an important biomechanical quantity in human movement analyses and has been estimated using different quantities including external, internal and joint work. The goal of this study was to investigate the relationships between these traditionally used estimates of mechanical work in human walking and to assess whether they can be used as accurate estimates of musculotendon and/or muscle fiber work. A muscle-actuated forward dynamics walking simulation was generated to quantify each of the mechanical work measures. Total joint work (i.e. the time integral of absolute joint power over a full gait cycle) was found to underestimate total musculotendon work due to agonist-antagonist co-contractions, despite the effect of biarticular muscle work and passive joint work, which acted to decrease the underestimation. We did find that when the net passive joint work over the gait cycle is negligible, net joint work (i.e. the time integral of net joint power) was comparable to the net musculotendon work (and net muscle fiber work because net tendon work is zero over a complete gait cycle). Thus, during walking conditions when passive joint work is negligible, net joint work may be used as an estimate of net muscle work. Neither total external nor total internal work (nor their sum) provided a reasonable estimate of total musculotendon work. We conclude that joint work is limited in its ability to estimate musculotendon work, and that external and internal work should not be used as an estimation of musculotendon work.

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Section: Discussionmentioning

confidence: 99%

The relationships between muscle, external, internal and joint mechanical work during normal walking

Sasaki

Neptune

Kautz

2009

Journal of Experimental Biology

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“…That is, the joints of the prostheses can either store or dissipate energy, but cannot provide net power over a gait cycle. The inability to deliver joint power significantly impairs the ability of these prostheses to restore many locomotive functions, including walking up stairs and up slopes, running, and jumping, all of which require significant net positive power at the knee joint, ankle joint or both (Winter and Sienko 1988;DeVita et al 1996;Jacobs et al 1996;Prilutsky et al 1996;Nagano et al 1998;Riener et al 1999;Nadeau et al 2003). Furthermore, although less obvious, even biomechanically normal walking requires positive power output at the knee joint and significant net positive power output at the ankle joint (Winter 1991).…”

Section: Motivationmentioning

confidence: 99%

Design and Control of a Powered Transfemoral Prosthesis

Sup

Bohara

Goldfarb

2008

The International Journal of Robotics Research

462

353

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The paper describes the design and control of a transfemoral prosthesis with powered knee and ankle joints. The initial prototype is a pneumatically actuated powered-tethered device, which is intended to serve as a laboratory test bed for a subsequent self-powered version. The prosthesis design is described, including its kinematic optimization and the design of a three-axis socket load cell that measures the forces and moments of interaction between the socket and prosthesis. A gait controller is proposed based on the use of passive impedance functions that coordinates the motion of the prosthesis with the user during level walking. The control approach is implemented on the prosthesis prototype and experimental results are shown that demonstrate the promise of the active prosthesis and control approach in restoring fully powered level walking to the user.

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“…The biarticular gastrocnemius muscles can theoretically transfer mechanical energy to and from the ankle joint via the knee and/or hip (Neptune et al, 2004a;Zajac et al, 2002). However, according to a computer simulation analysis, during the stance phase of walking the energy transfers between the knee and ankle do not significantly confound the accuracy of muscle work estimates based on net moment work (Prilutsky et al, 1996). In addition, coactivation of antagonist muscles could have confounded estimates of plantar flexor muscle work that are based on net ankle joint mechanical power.…”

Section: G S Sawicki and D P Ferrismentioning

confidence: 99%

Powered ankle exoskeletons reveal the metabolic cost of plantar flexor mechanical work during walking with longer steps at constant step frequency

Sawicki

Ferris

2009

Journal of Experimental Biology

134

124

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SUMMARYWe examined the metabolic cost of plantar flexor muscle-tendon mechanical work during human walking. Nine healthy subjects walked at constant step frequency on a motorized treadmill at speeds corresponding to 80% (1.00 m s . In each condition subjects donned robotic ankle exoskeletons on both legs. The exoskeletons were powered by artificial pneumatic muscles and controlled using soleus electromyography (i.e. proportional myoelectric control). We measured subjects' metabolic energy expenditure and exoskeleton mechanics during both unpowered and powered walking to test the hypothesis that ankle plantarflexion requires more net metabolic power (W kg Declining ankle muscle-tendon 'apparent efficiency' suggests an increase in ankle plantar flexor muscle work relative to Achilles' tendon elastic energy recoil during walking with longer steps. However, previously stored elastic energy in Achilles' tendon still probably contributes up to 34% of ankle muscle-tendon positive work even at the longest step lengths we tested. Across the range of step lengths we studied, the human ankle muscle-tendon system performed 34-40% of the total lower-limb positive mechanical work but accounted for only 7-26% of the net metabolic cost of walking. Supplementary material available online at

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Comparison of mechanical energy expenditure of joint moments and muscle forces during human locomotion

Cited by 55 publications

References 28 publications

The relationships between muscle, external, internal and joint mechanical work during normal walking

The relationships between muscle, external, internal and joint mechanical work during normal walking

Design and Control of a Powered Transfemoral Prosthesis

Powered ankle exoskeletons reveal the metabolic cost of plantar flexor mechanical work during walking with longer steps at constant step frequency

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