Differences in contractile behaviour between the soleus and medial gastrocnemius muscles during human walking

Cronin, Neil J.; Avela, Janne; Finni, Taija; Peltonen, Jussi

doi:10.1242/jeb.078196

Cited by 69 publications

(76 citation statements)

References 29 publications

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“…The soleus, lateral gastrocnemius and medial gastrocnemius were each modelled with a separate tendon, as opposed to one shared tendon. It is unclear which modelling choice is more appropriate for our study, but our fiber and tendon excursions were consistent with experimental ultrasound studies (Fukunaga et al, 2001;Lichtwark and Wilson, 2006;Cronin et al, 2010;Rubenson et al, 2012;Cronin et al, 2013). Moreover, qualitative trends in elastic element negative, positive and net work (Fig.…”

Section: Discussionsupporting

confidence: 82%

Muscle-tendon mechanics explain unexpected effects of exoskeleton assistance on metabolic rate during walking

Jackson

Dembia

Delp

et al. 2017

Journal of Experimental Biology

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The goal of this study was to gain insight into how ankle exoskeletons affect the behavior of the plantarflexor muscles during walking. Using data from previous experiments, we performed electromyographydriven simulations of musculoskeletal dynamics to explore how changes in exoskeleton assistance affected plantarflexor muscletendon mechanics, particularly for the soleus. We used a model of muscle energy consumption to estimate individual muscle metabolic rate. As average exoskeleton torque was increased, while no net exoskeleton work was provided, a reduction in tendon recoil led to an increase in positive mechanical work performed by the soleus muscle fibers. As net exoskeleton work was increased, both soleus muscle fiber force and positive mechanical work decreased. Trends in the sum of the metabolic rates of the simulated muscles correlated well with trends in experimentally observed whole-body metabolic rate (R 2 =0.9), providing confidence in our model estimates. Our simulation results suggest that different exoskeleton behaviors can alter the functioning of the muscles and tendons acting at the assisted joint. Furthermore, our results support the idea that the series tendon helps reduce positive work done by the muscle fibers by storing and returning energy elastically. We expect the results from this study to promote the use of electromyography-driven simulations to gain insight into the operation of muscle-tendon units and to guide the design and control of assistive devices.

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Section: Discussionsupporting

confidence: 82%

Muscle-tendon mechanics explain unexpected effects of exoskeleton assistance on metabolic rate during walking

Jackson

Dembia

Delp

et al. 2017

Journal of Experimental Biology

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“…An ultrasound probe (7.5 MHz linear array probe with 60 mm field width, Telemed, EchoBlaster128, Lithuania) was attached over the medial gastrocnemius muscle visualizing both medial gastrocnemius (MG) and soleus muscles simultaneously (7). Images were collected at 80 Hz and stored on a PC.…”

Section: Muscle Fascicle Length and Pennation Anglementioning

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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“…Heterogeneity of muscle lengths and velocity between synergists during contraction may be explained by such differences in the neural drive, but also by architectural properties, such as pennation angle and fiber type composition (Armstrong and Phelps, 1984). Previous studies have shown that muscle activation and muscle fascicle deformation differ between ankle plantar-flexors (Cronin et al, 2013;Maas et al, 2009). Also, the force produced by ankle plantar-flexors and their contractile behavior has been reported to be quite diverse (Daley, 2003;Prilutsky et al, 1996).…”

Section: Heterogeneity Of Contraction Behavior and Muscle Activation mentioning

confidence: 99%

Longitudinal and transversal displacements between triceps surae muscles during locomotion of the rat

Bernabei

Dieën

Maas

2017

Journal of Experimental Biology

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The functional consequences of differential muscle activation and contractile behavior between mechanically coupled synergists are still poorly understood. Even though synergistic muscles exert similar mechanical effects at the joint they span, differences in the anatomy, morphology and neural drive may lead to non-uniform contractile conditions. This study aimed to investigate the patterns of activation and contractile behavior of triceps surae muscles, to understand how these contribute to the relative displacement between the one-joint soleus (SO) and two-joint lateral gastrocnemius (LG) muscle bellies and their distal tendons during locomotion in the rat. In seven rats, muscle belly lengths and muscle activation during level and upslope trotting were measured by sonomicrometry crystals and electromyographic electrodes chronically implanted in the SO and LG. Length changes of muscle-tendon units (MTUs) and tendon fascicles were estimated based on joint kinematics and muscle belly lengths. Distances between implanted crystals were further used to assess longitudinal and transversal deformations of the intermuscular volume between the SO and LG. For both slope conditions, we observed differential timing of muscle activation as well as substantial differences in contraction speeds between muscle bellies (maximal relative speed 55.9 mm s −1 ). Muscle lengths and velocities did not differ significantly between level and upslope locomotion, only EMG amplitude of the LG was affected by slope. Relative displacements between SO and LG MTUs were found in both longitudinal and transversal directions, yielding an estimated maximal length change difference of 2.0 mm between their distal tendons. Such relative displacements may have implications for the force exchanged via intermuscular and intertendinous pathways.

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Differences in contractile behaviour between the soleus and medial gastrocnemius muscles during human walking

Cited by 69 publications

References 29 publications

Muscle-tendon mechanics explain unexpected effects of exoskeleton assistance on metabolic rate during walking

Muscle-tendon mechanics explain unexpected effects of exoskeleton assistance on metabolic rate during walking

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

Longitudinal and transversal displacements between triceps surae muscles during locomotion of the rat

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