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Three-Dimensional Muscle Architecture and Comprehensive Dynamic Properties of Rabbit Gastrocnemius, Plantaris and Soleus: Input for Simulation Studies.

Siebert T, Leichsenring K, Rode C, Wick C, Stutzig N, Schubert H, Blickhan R, Böl M - PLoS ONE (2015)

Bottom Line: Simulation results depend heavily on rough parameter estimates often obtained by scaling of one muscle parameter set.The lowest effect strength for soleus supports the idea that these effects adapt to muscle function.The careful acquisition of typical dynamical parameters (e.g. force-length and force-velocity relations, force elongation relations of passive components), enhancement and depression effects, and 3D muscle architecture of calf muscles provides valuable comprehensive datasets for e.g. simulations with neuro-muscular models, development of more realistic muscle models, or simulation of muscle packages.

View Article: PubMed Central - PubMed

Affiliation: Department of Sport and Motion Science, University of Stuttgart, Stuttgart, Germany.

ABSTRACT
The vastly increasing number of neuro-muscular simulation studies (with increasing numbers of muscles used per simulation) is in sharp contrast to a narrow database of necessary muscle parameters. Simulation results depend heavily on rough parameter estimates often obtained by scaling of one muscle parameter set. However, in vivo muscles differ in their individual properties and architecture. Here we provide a comprehensive dataset of dynamic (n = 6 per muscle) and geometric (three-dimensional architecture, n = 3 per muscle) muscle properties of the rabbit calf muscles gastrocnemius, plantaris, and soleus. For completeness we provide the dynamic muscle properties for further important shank muscles (flexor digitorum longus, extensor digitorum longus, and tibialis anterior; n = 1 per muscle). Maximum shortening velocity (normalized to optimal fiber length) of the gastrocnemius is about twice that of soleus, while plantaris showed an intermediate value. The force-velocity relation is similar for gastrocnemius and plantaris but is much more bent for the soleus. Although the muscles vary greatly in their three-dimensional architecture their mean pennation angle and normalized force-length relationships are almost similar. Forces of the muscles were enhanced in the isometric phase following stretching and were depressed following shortening compared to the corresponding isometric forces. While the enhancement was independent of the ramp velocity, the depression was inversely related to the ramp velocity. The lowest effect strength for soleus supports the idea that these effects adapt to muscle function. The careful acquisition of typical dynamical parameters (e.g. force-length and force-velocity relations, force elongation relations of passive components), enhancement and depression effects, and 3D muscle architecture of calf muscles provides valuable comprehensive datasets for e.g. simulations with neuro-muscular models, development of more realistic muscle models, or simulation of muscle packages.

No MeSH data available.


Related in: MedlinePlus

Muscle properties of GAS, PLA, and SOL.The black curves indicate mean values, whereas the grey areas depict the standard deviations. First row: force–length (fl) relation. Fim is the maximum isometric muscle force, lCC and lCCopt are the length and the optimal length of the contractile component, respectively. To avoid muscle damage, the muscles were lengthened until passive forces reached about 0.2 Fim (marked with a white circle). Second row: force–velocity (fv) relation. vCCmax is the maximal shortening velocity of the contractile component. Third row: Force–strain relation of the series elastic component (SEC). ΔlSEC and lSEC0 are the length change and the slack length of the series elastic component, respectively. Last row: Force–strain relation of the parallel elastic component (PEC). ΔlPEC and lPEC0 are the length change and the slack length of the parallel elastic component, respectively.
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pone.0130985.g003: Muscle properties of GAS, PLA, and SOL.The black curves indicate mean values, whereas the grey areas depict the standard deviations. First row: force–length (fl) relation. Fim is the maximum isometric muscle force, lCC and lCCopt are the length and the optimal length of the contractile component, respectively. To avoid muscle damage, the muscles were lengthened until passive forces reached about 0.2 Fim (marked with a white circle). Second row: force–velocity (fv) relation. vCCmax is the maximal shortening velocity of the contractile component. Third row: Force–strain relation of the series elastic component (SEC). ΔlSEC and lSEC0 are the length change and the slack length of the series elastic component, respectively. Last row: Force–strain relation of the parallel elastic component (PEC). ΔlPEC and lPEC0 are the length change and the slack length of the parallel elastic component, respectively.

Mentions: Active and passive muscle properties vary considerably between GAS, PLA, and SOL. We found significant differences for the parameters lCCopt, vCCmax, curv, ΔlSEC1/lSEC0, k, lSEC0, and lPEC0 (Table 2). All experimental force–velocity relationships feature the typical hyperbolic shape (Fig 3, second row) observed by [5]. Maximum shortening velocity of GAS (13.5 ± 1.7 lCCopt/s) is about twice the value of SOL (6.4 ± 1.0 lCCopt/s). Maximum shortening velocity of PLA (10.1 ± 3.3 lCCopt/s) is in between these values. The curv values of the force-velocity relation are similar for GAS and PLA (0.47 ± 0.09 and 0.41 ± 0.16, respectively) but about three times the value for SOL (0.15 ± 0.05). The calf muscles exhibited a characteristic force–length dependency (Fig 3, upper row) which is attributable to the muscle fiber force–length relationship [12]. Maximum isometric forces produced at optimum muscle lengths by GAS, PLA, and SOL are 161.3 ± 18.2 N, 86.4 ± 21.3 N, and 24.1 ± 5.8 N, respectively. Considering a muscle tissue density of 1.056 g/cm3 [52], as well as a mean muscle mass (Table 1) and mean optimal fiber length (Table 2), the cross-sectional area (CSA) can be calculated (GAS: 8.63 cm2, PLA: 4.57 cm2, SOL: 1.44 cm2). This leads to similar mean muscle stresses of 18.9, 18.8, and 17.0 N/cm2 for GAS, PLA, and SOL, respectively. Optimum fiber lengths of SOL (22.1 ± 4.5 mm) are longer than those of PLA (13.2 ± 1.3 mm) enabling a much larger working range of SOL. Series and parallel elastic components possess typical [6] nonlinear force–strain characteristics (Fig 3). The standard deviations of the determined muscle properties are small, with the exception of the force–strain relation of the parallel elastic component (Fig 3, bottom row) which is about three times the standard deviation observed for the SEC.


Three-Dimensional Muscle Architecture and Comprehensive Dynamic Properties of Rabbit Gastrocnemius, Plantaris and Soleus: Input for Simulation Studies.

Siebert T, Leichsenring K, Rode C, Wick C, Stutzig N, Schubert H, Blickhan R, Böl M - PLoS ONE (2015)

Muscle properties of GAS, PLA, and SOL.The black curves indicate mean values, whereas the grey areas depict the standard deviations. First row: force–length (fl) relation. Fim is the maximum isometric muscle force, lCC and lCCopt are the length and the optimal length of the contractile component, respectively. To avoid muscle damage, the muscles were lengthened until passive forces reached about 0.2 Fim (marked with a white circle). Second row: force–velocity (fv) relation. vCCmax is the maximal shortening velocity of the contractile component. Third row: Force–strain relation of the series elastic component (SEC). ΔlSEC and lSEC0 are the length change and the slack length of the series elastic component, respectively. Last row: Force–strain relation of the parallel elastic component (PEC). ΔlPEC and lPEC0 are the length change and the slack length of the parallel elastic component, respectively.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4482742&req=5

pone.0130985.g003: Muscle properties of GAS, PLA, and SOL.The black curves indicate mean values, whereas the grey areas depict the standard deviations. First row: force–length (fl) relation. Fim is the maximum isometric muscle force, lCC and lCCopt are the length and the optimal length of the contractile component, respectively. To avoid muscle damage, the muscles were lengthened until passive forces reached about 0.2 Fim (marked with a white circle). Second row: force–velocity (fv) relation. vCCmax is the maximal shortening velocity of the contractile component. Third row: Force–strain relation of the series elastic component (SEC). ΔlSEC and lSEC0 are the length change and the slack length of the series elastic component, respectively. Last row: Force–strain relation of the parallel elastic component (PEC). ΔlPEC and lPEC0 are the length change and the slack length of the parallel elastic component, respectively.
Mentions: Active and passive muscle properties vary considerably between GAS, PLA, and SOL. We found significant differences for the parameters lCCopt, vCCmax, curv, ΔlSEC1/lSEC0, k, lSEC0, and lPEC0 (Table 2). All experimental force–velocity relationships feature the typical hyperbolic shape (Fig 3, second row) observed by [5]. Maximum shortening velocity of GAS (13.5 ± 1.7 lCCopt/s) is about twice the value of SOL (6.4 ± 1.0 lCCopt/s). Maximum shortening velocity of PLA (10.1 ± 3.3 lCCopt/s) is in between these values. The curv values of the force-velocity relation are similar for GAS and PLA (0.47 ± 0.09 and 0.41 ± 0.16, respectively) but about three times the value for SOL (0.15 ± 0.05). The calf muscles exhibited a characteristic force–length dependency (Fig 3, upper row) which is attributable to the muscle fiber force–length relationship [12]. Maximum isometric forces produced at optimum muscle lengths by GAS, PLA, and SOL are 161.3 ± 18.2 N, 86.4 ± 21.3 N, and 24.1 ± 5.8 N, respectively. Considering a muscle tissue density of 1.056 g/cm3 [52], as well as a mean muscle mass (Table 1) and mean optimal fiber length (Table 2), the cross-sectional area (CSA) can be calculated (GAS: 8.63 cm2, PLA: 4.57 cm2, SOL: 1.44 cm2). This leads to similar mean muscle stresses of 18.9, 18.8, and 17.0 N/cm2 for GAS, PLA, and SOL, respectively. Optimum fiber lengths of SOL (22.1 ± 4.5 mm) are longer than those of PLA (13.2 ± 1.3 mm) enabling a much larger working range of SOL. Series and parallel elastic components possess typical [6] nonlinear force–strain characteristics (Fig 3). The standard deviations of the determined muscle properties are small, with the exception of the force–strain relation of the parallel elastic component (Fig 3, bottom row) which is about three times the standard deviation observed for the SEC.

Bottom Line: Simulation results depend heavily on rough parameter estimates often obtained by scaling of one muscle parameter set.The lowest effect strength for soleus supports the idea that these effects adapt to muscle function.The careful acquisition of typical dynamical parameters (e.g. force-length and force-velocity relations, force elongation relations of passive components), enhancement and depression effects, and 3D muscle architecture of calf muscles provides valuable comprehensive datasets for e.g. simulations with neuro-muscular models, development of more realistic muscle models, or simulation of muscle packages.

View Article: PubMed Central - PubMed

Affiliation: Department of Sport and Motion Science, University of Stuttgart, Stuttgart, Germany.

ABSTRACT
The vastly increasing number of neuro-muscular simulation studies (with increasing numbers of muscles used per simulation) is in sharp contrast to a narrow database of necessary muscle parameters. Simulation results depend heavily on rough parameter estimates often obtained by scaling of one muscle parameter set. However, in vivo muscles differ in their individual properties and architecture. Here we provide a comprehensive dataset of dynamic (n = 6 per muscle) and geometric (three-dimensional architecture, n = 3 per muscle) muscle properties of the rabbit calf muscles gastrocnemius, plantaris, and soleus. For completeness we provide the dynamic muscle properties for further important shank muscles (flexor digitorum longus, extensor digitorum longus, and tibialis anterior; n = 1 per muscle). Maximum shortening velocity (normalized to optimal fiber length) of the gastrocnemius is about twice that of soleus, while plantaris showed an intermediate value. The force-velocity relation is similar for gastrocnemius and plantaris but is much more bent for the soleus. Although the muscles vary greatly in their three-dimensional architecture their mean pennation angle and normalized force-length relationships are almost similar. Forces of the muscles were enhanced in the isometric phase following stretching and were depressed following shortening compared to the corresponding isometric forces. While the enhancement was independent of the ramp velocity, the depression was inversely related to the ramp velocity. The lowest effect strength for soleus supports the idea that these effects adapt to muscle function. The careful acquisition of typical dynamical parameters (e.g. force-length and force-velocity relations, force elongation relations of passive components), enhancement and depression effects, and 3D muscle architecture of calf muscles provides valuable comprehensive datasets for e.g. simulations with neuro-muscular models, development of more realistic muscle models, or simulation of muscle packages.

No MeSH data available.


Related in: MedlinePlus