The mechanics and energetics of human walking and running: a joint level perspective

Farris, Dominic James; Sawicki, Gregory S.

doi:10.1098/rsif.2011.0182

Cited by 381 publications

(321 citation statements)

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“…Also, Hansen et al (7) showed that at walking speeds above those preferred, the net positive work done at the ankle increased. When switching from walking to running gait, the relative contribution of ankle positive power output to total positive power output also increased (6). It was inferred from these data that plantar-flexor muscle mechanics were adjusted to accommodate faster walking speeds and then again with the switch to running gait.…”

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confidence: 74%

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Human medial gastrocnemius force–velocity behavior shifts with locomotion speed and gait

Farris

Sawicki

2012

Proc. Natl. Acad. Sci. U.S.A.

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Humans walk and run over a wide range of speeds with remarkable efficiency. For steady locomotion, moving at different speeds requires the muscle-tendon units of the leg to modulate the amount of mechanical power the limb absorbs and outputs in each step. How individual muscles adapt their behavior to modulate limb power output has been examined using computer simulation and animal models, but has not been studied in vivo in humans. In this study, we used a combination of ultrasound imaging and motion analysis to examine how medial gastrocnemius (MG) muscletendon unit behavior is adjusted to meet the varying mechanical demands of different locomotor speeds during walking and running in humans. The results highlighted key differences in MG fascicle-shortening velocity with both locomotor speed and gait. Fascicle-shortening velocity at the time of peak muscle force production increased with walking speed, impairing the ability of the muscle to produce high peak forces. Switching to a running gait at 2.0 m·s −1 caused fascicle shortening at the time of peak force production to shift to much slower velocities. This velocity shift facilitated a large increase in peak muscle force and an increase in MG power output. MG fascicle velocity may be a key factor that limits the speeds humans choose to walk at, and may explain the transition from walking to running. This finding is consistent with previous modeling studies.muscle mechanics | biomechanics | preferred transition speed A nkle plantar-flexor muscles are a vital source of mechanical power for human locomotion (1, 2). During walking, plantar-flexor muscles provide body weight support, contribute to propulsion, and accelerate the limb into swing (3). In running, the ankle acts in a spring-like manner, absorbing energy in plantarflexor muscle-tendon units during early stance and providing energy to accelerate the body in late stance (1). The mechanical work required to produce whole-body movement during walking and running varies between gaits and across speeds (4, 5). Thus, the plantar-flexors may need to adjust their mechanical work output with gait and speed to meet the changing demands on their contribution to total mechanical work.A recent experimental study in humans used an inverse-dynamics approach to examine how the mechanical power outputs of muscles acting at the hip, knee, and ankle joint were modulated for walking and running at a range of speeds (6). It was found that positive power output at the ankle, in conjunction with the knee and hip, increased with walking speed. Also, Hansen et al. (7) showed that at walking speeds above those preferred, the net positive work done at the ankle increased. When switching from walking to running gait, the relative contribution of ankle positive power output to total positive power output also increased (6). It was inferred from these data that plantar-flexor muscle mechanics were adjusted to accommodate faster walking speeds and then again with the switch to running gait. If this is truly the case, then it may hav...

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confidence: 74%

“…A recent experimental study in humans used an inverse-dynamics approach to examine how the mechanical power outputs of muscles acting at the hip, knee, and ankle joint were modulated for walking and running at a range of speeds (6). It was found that positive power output at the ankle, in conjunction with the knee and hip, increased with walking speed.…”

mentioning

confidence: 99%

Human medial gastrocnemius force–velocity behavior shifts with locomotion speed and gait

Farris

Sawicki

2012

Proc. Natl. Acad. Sci. U.S.A.

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201

256

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“…Humans tend to prefer walking speeds that minimize gross energy cost of walking per unit distance (6,12). Triceps surae muscles may make a relatively large contribution to changes in whole body energy cost in walking with changes in walking speed since it has been shown using EMG-driven simulations that triceps surae were the only muscles of the 11 analyzed lower limb muscles that decreased their force generation ability with increasing walking speed, requiring greater activation to maintain required force generation (3).…”

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confidence: 99%

Slower Walking Speed in Older Men Improves Triceps Surae Force Generation Ability

Stenroth

Sipilä

Finni

et al. 2017

Medicine &Amp; Science in Sports &Amp; Exercise

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Purpose: Older adults walk slower than young adults but it is not known why. Previous research suggests that ankle plantarflexors may have a crucial role in the reduction of walking speed. The purpose of this study was to investigate age-related differences in triceps surae muscle-tendon function during walking to further investigate the role of plantarflexors in the age-related reduction of walking speed. Methods: Medial gastrocnemius and soleus muscle fascicle lengths were measured using ultrasound imaging during walking from 13 young (25±4yrs) men at preferred walking speed, and from 13 older (73±5yrs) men at preferred speed and at the young men's preferred speed. Muscle-tendon unit lengths were calculated from joint kinematics and tendinous tissue lengths were calculated by subtracting muscle lengths from muscle-tendon unit lengths. In addition, ground reaction forces and electromyographic activity of medial gastrocnemius and soleus were measured. Results: In both medial gastrocnemius and soleus it was observed that at preferred walking speed, older men used a narrower muscle fascicle operating range and lower shortening velocity at the estimated time of triceps surae peak force generation compared to young men. Fascicles also accounted for a lower proportion of muscle-tendon unit length changes during the stance phase in older compared to young men. Significant differences in triceps surae muscle function were not observed between age groups when compared at matched walking speed. Conclusions: In older men, walking at preferred speed allows triceps surae muscles to generate force with more favorable shortening velocity and to enhance use of tendinous tissue elasticity compared to walking at young men's preferred speed. The results suggest that older men may prefer slower walking speeds to compensate for decreased plantarflexor strength.

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“…4). It is not entirely clear why, in the CHF group, the contributions of each joint to the total mechanical work resemble those in healthy young adults (Farris and Sawicki, 2012), especially considering the reduced muscle volume of the ankle plantarflexors. A first possible explanation might be found in the hip flexor function.…”

Section: What Dictates Preferred Walking Speed and Joint Work Modulatmentioning

confidence: 99%

Gait analysis in chronic heart failure: The calf as a locus of impaired walking capacity

Panizzolo

Maiorana

Naylor

et al. 2014

Journal of Biomechanics

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a b s t r a c tReduced walking capacity, a hallmark of chronic heart failure (CHF), is strongly correlated with hospitalization and morbidity. The aim of this work was to perform a detailed biomechanical gait analysis to better identify mechanisms underlying reduced walking capacity in CHF. Inverse dynamic analyses were conducted in CHF patients and age-and exercise level-matched control subjects on an instrumented treadmill at self-selected treadmill walking speeds and at speeds representing þ 20% and -20% of the subjects' preferred speed. Surprisingly, no difference in preferred speed was observed between groups, possibly explained by an optimization of the mechanical cost of transport in both groups (the mechanical cost to travel a given distance; J/kg/m). The majority of limb kinematics and kinetics were also similar between groups, with the exception of greater ankle dorsiflexion angles during stance in CHF. Nevertheless, over two times greater ankle plantarflexion work during stance and per distance traveled is required for a given triceps surae muscle volume in CHF patients. This, together with a greater reliance on the ankle compared to the hip to power walking in CHF patients, especially at faster speeds, may contribute to the earlier onset of fatigue in CHF patients. This observation also helps explain the high correlation between triceps surae muscle volume and exercise capacity that has previously been reported in CHF. Considering the key role played by the plantarflexors in powering walking and their association with exercise capacity, our findings strongly suggest that exercise-based rehabilitation in CHF should not omit the ankle muscle group.

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The mechanics and energetics of human walking and running: a joint level perspective

Cited by 381 publications

References 32 publications

Human medial gastrocnemius force–velocity behavior shifts with locomotion speed and gait

Human medial gastrocnemius force–velocity behavior shifts with locomotion speed and gait

Slower Walking Speed in Older Men Improves Triceps Surae Force Generation Ability

Gait analysis in chronic heart failure: The calf as a locus of impaired walking capacity

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