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Journal ArticleDOI

Architectural and functional features of human triceps surae muscles during contraction

01 Aug 1998-Journal of Applied Physiology (American Physiological Society)-Vol. 85, Iss: 2, pp 398-404
TL;DR: Different lengths and angles of fascicles, and their changes by contraction, might be related to differences in force-producing capabilities of the muscles and elastic characteristics of tendons and aponeuroses.
Abstract: Architectural properties of the triceps surae muscles were determined in vivo for six men. The ankle was positioned at 15° dorsiflexion (−15°) and 0, 15, and 30° plantar flexion, with the knee set ...
Citations
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Journal ArticleDOI
TL;DR: Full understanding of these physiological processes will provide the physiological basis for understanding of tissue overloading and injury seen in both tendons and muscle with repetitive work and leisure time physical activity.
Abstract: The extracellular matrix (ECM), and especially the connective tissue with its collagen, links tissues of the body together and plays an important role in the force transmission and tissue structure maintenance especially in tendons, ligaments, bone, and muscle. The ECM turnover is influenced by physical activity, and both collagen synthesis and degrading metalloprotease enzymes increase with mechanical loading. Both transcription and posttranslational modifications, as well as local and systemic release of growth factors, are enhanced following exercise. For tendons, metabolic activity, circulatory responses, and collagen turnover are demonstrated to be more pronounced in humans than hitherto thought. Conversely, inactivity markedly decreases collagen turnover in both tendon and muscle. Chronic loading in the form of physical training leads both to increased collagen turnover as well as, dependent on the type of collagen in question, some degree of net collagen synthesis. These changes will modify the mechanical properties and the viscoelastic characteristics of the tissue, decrease its stress, and likely make it more load resistant. Cross-linking in connective tissue involves an intimate, enzymatical interplay between collagen synthesis and ECM proteoglycan components during growth and maturation and influences the collagen-derived functional properties of the tissue. With aging, glycation contributes to additional cross-linking which modifies tissue stiffness. Physiological signaling pathways from mechanical loading to changes in ECM most likely involve feedback signaling that results in rapid alterations in the mechanical properties of the ECM. In developing skeletal muscle, an important interplay between muscle cells and the ECM is present, and some evidence from adult human muscle suggests common signaling pathways to stimulate contractile and ECM components. Unaccostumed overloading responses suggest an important role of ECM in the adaptation of myofibrillar structures in adult muscle. Development of overuse injury in tendons involve morphological and biochemical changes including altered collagen typing and fibril size, hypervascularization zones, accumulation of nociceptive substances, and impaired collagen degradation activity. Counteracting these phenomena requires adjusted loading rather than absence of loading in the form of immobilization. Full understanding of these physiological processes will provide the physiological basis for understanding of tissue overloading and injury seen in both tendons and muscle with repetitive work and leisure time physical activity.

1,365 citations

Journal ArticleDOI
TL;DR: The basic architectural properties of human upper and lower extremity muscles are described and the ability of muscles to change their architecture in response to immobilization, eccentric exercise, and surgical tendon transfer is reviewed.
Abstract: Skeletal muscle architecture is the structural property of whole muscles that dominates their function. This review describes the basic architectural properties of human upper and lower extremity muscles. The designs of various muscle groups in humans and other species are analyzed from the point of view of optimizing function. Muscle fiber arrangement and motor unit arrangement is discussed in terms of the control of movement. Finally, the ability of muscles to change their architecture in response to immobilization, eccentric exercise, and surgical tendon transfer is reviewed. Future integrative physiological studies will provide insights into the mechanisms by which such adaptations occur. It is likely that muscle fibers transduce both stress and strain and respond by modifying sarcomere number in a way more suited to the new biomechanical environment.

1,015 citations

Journal ArticleDOI
TL;DR: The focus of this paper is on the details involved in the first two steps of forward dynamic neuromusculoskeletal modeling, since these are the most challenging to the biomechanician.
Abstract: This paper provides an overview of forward dynamic neuromusculoskeletal modeling The aim of such models is to estimate or predict muscle forces, joint moments, and/or joint kinematics from neural signals This is a four-step process In the first step, muscle activation dynamics govern the transformation from the neural signal to a measure of muscle activation—a time varying parameter between 0 and 1 In the second step, muscle contraction dynamics characterize how muscle activations are transformed into muscle forces The third step requires a model of the musculoskeletal geometry to transform muscle forces to joint moments Finally, the equations of motion allow joint moments to be transformed into joint movements Each step involves complex nonlinear relationships The focus of this paper is on the details involved in the first two steps, since these are the most challenging to the biomechanician The global process is then explained through applications to the study of predicting isometric elbow moments and dynamic knee kinetics

780 citations


Cites methods from "Architectural and functional featur..."

  • ...Kawakami et al. (1998) used ultrasound to show that the medial gastrocnemius muscle can change its pennation angle from 22° to 67°, depending on joint angles and amount of muscle activation....

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Journal ArticleDOI
TL;DR: Two important features emerged: the muscle contracted near–isometrically in the stance phase, with the fascicles operating at ca.
Abstract: In the present study we investigated in vivo length changes in the fascicles and tendon of the human gastrocnemius medialis (GM) muscle during walking. The experimental protocol involved real-time ultrasound scanning of the GM muscle, recording of the electrical activity of the muscle, measurement of knee- and ankle-joint rotations, and measurement of ground reaction forces in six men during walking at 3 km h(-1) on a treadmill. Fascicular lengths were measured from the sonographs recorded. Musculotendon complex length changes were estimated from anatomical and joint kinematic data. Tendon length changes were obtained combining the musculotendon complex and fascicular length-change data. The fascicles followed a different length-change pattern from those of the musculotendon complex and tendon throughout the step cycle. Two important features emerged: (i) the muscle contracted near-isometrically in the stance phase, with the fascicles operating at ca. 50 mm; and (ii) the tendon stretched by ca. 7 mm during single support, and recoiled in push-off. The behaviour of the muscle in our experiment indicates consumption of minimal metabolic energy for eliciting the contractile forces required to support and displace the body. On the other hand, the spring-like behaviour of the tendon indicates storage and release of elastic-strain energy. Either of the two mechanisms would favour locomotor economy

593 citations

Journal ArticleDOI
TL;DR: The findings suggest that the elastic recoil takes place not as a spring-like bouncing but as a catapult action in natural human walking.
Abstract: The present study was designed to explore how the interaction between the fascicles and tendinous tissues is involved in storage and utilization of elastic energy during human walking. Eight male subjects walked with a natural cadence (1.4 ± 0.1 m/s) on a 10-m-long force plate system. In vivo techniques were employed to record the Achilles tendon force and to scan real-time fascicle lengths for two muscles (medial gastrocnemius and soleus). The results showed that tendinous tissues of both medial gastrocnemius and soleus muscles lengthened slowly throughout the single-stance phase and then recoiled rapidly close to the end of the ground contact. However, the fascicle length changes demonstrated different patterns and amplitudes between two muscles. The medial gastrocnemius fascicles were stretched during the early single-stance phase and then remained isometrically during the late-stance phase. In contrast, the soleus fascicles were lengthened until the end of the single-stance phase. These findings suggest that the elastic recoil takes place not as a spring-like bouncing but as a catapult action in natural human walking. The interaction between the muscle fascicles and tendinous tissues plays an important role in the process of release of elastic energy, although the leg muscles, which are commonly accepted as synergists, do not have similar mechanical behavior of fascicles in this catapult action.

444 citations

References
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Journal ArticleDOI
TL;DR: In this paper, the mean fibre type proportions of each muscle were examined and the spatial distribution of the fibre types was examined in order to determine whether this was random or not, and the number of closed fibers observed in the actual samples was compared statistically with the number expected to occur in a hexagonal lattice model, assuming a random distribution.

2,114 citations

Journal ArticleDOI
TL;DR: The architectural features of the major knee extensors and flexors and ankle plantarflexors and dorsiflexors were determined in three human cadavers and grouped according to whether they showed a predilection for tension or velocity of shortening.
Abstract: The architectural features of the major knee extensors and flexors and ankle plantar flexors and dorsiflexors were determined in three human cadavers. There was marked uniformity of fiber length throughout a given muscle and a trend toward similar fiber lengths within muscles of a synergistic group.

923 citations


"Architectural and functional featur..." refers background in this paper

  • ...This means that the number of sarcomeres in series is the largest for this muscle, which illustrates eminent velocity potential of LG, as suggested previously (11, 12, 32)....

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  • ...Although it has been shown that there is marked uniformity in fiber length (4, 32) and fascicle length (4, 24) throughout a muscle, some studies have reported heterogeneity of fascicle angles (24) and even fascicle lengths (11, 21) along the length of the muscle....

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  • ...The triceps surae muscles are the main synergists for plantar flexion (6, 18), but they have different architectural properties, such as muscle length, fascicle length, and pennation angles (3, 4, 32)....

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  • ...Attempts have been made to determine the geometric arrangement of muscle fibers or fascicles (muscle architecture) in humans, and many attemtps have been based on measurements of cadaver specimens (3, 4, 11, 12, 29, 32)....

    [...]

  • ...Furthermore, many of the previous reports have been based on cadaver specimens (3, 4, 11, 12, 29, 32), and little data are available on muscle architecture in living human muscles, especially during contraction....

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Journal ArticleDOI
TL;DR: Intra-subject variability of joint moment patterns over the stride period was high at the knee and hip, but low at the ankle and in a recently defined total limb pattern, called support moment.

779 citations


"Architectural and functional featur..." refers background in this paper

  • ...In the stance phase of walking (foot contact-push-off), the knee joint angle changes between 0 and 30°, and the ankle joint angle ranges between 15° dorsiflexion and 0° plantar flexion (33)....

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Journal ArticleDOI
TL;DR: Rations of wet weight to predicted maximal tetanic tension for each muscle and group were calculated to compare the relative priority of muscle force versus muscle length‐velocity for a given mass of muscle, suggesting that velocity and/or displacement is a priority for the hamstrings, whereas force is apriority for the quadriceps and lower leg muscles.
Abstract: Force, velocity, and displacement properties of a muscle are determined in large part by its architectural design. The relative effect of muscle architecture on these physiological variables was studied by determining muscle weight, fiber length, average sarcomere length, and approximate angle of pinnation of 24 cat hind limb muscles. Muscle lengths ranged from 28.3 to 144 mm, whereas fiber lengths ranged from 8.4 to 105.5 mm. Generally, fiber to muscle length ratios were similar throughout a muscle. Estimated angles of pinnation of muscle fibers varied from 0 to 21 degrees with most having an angle of less than 10 degrees. The cross-sectional area of the knee extensors was similar to the knee flexors (16.43 vs. 16.83 cm2) whereas the cross-sectional area of the ankle extensors was more than six times greater than the ankle flexors (18.59 vs. 2.83 cm2). There was a 6.7-fold difference in the maximal force between muscles, when normalized to a constant weight, that could be attributed to architectural features. Ratios of wet weight to predicted maximal tetanic tension for each muscle and muscle group were calculated to compare the relative priority of muscle force versus muscle length-velocity for a given mass of muscle. These ratios varied from 0.4 to 4.84. The ratios suggest that velocity and/or displacement is a priority for the hamstrings, whereas force is a priority for the quadriceps and lower leg muscles. As much as a 12.6-fold difference in maximal velocity between muscles can be attributed to differences in fiber lengths. This can be compared to approximately a 2.5-fold difference in maximal velocity reported to occur as a result of biochemical (intrinsic) differences.

571 citations


"Architectural and functional featur..." refers background in this paper

  • ...Previous studies have not found a clear relationship between muscle architecture and fiber composition (2, 21), but the variation in force-generating capabilities among limb muscles is influenced more by differences in their architecture than those in their fiber types (1, 2, 23)....

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Journal ArticleDOI
TL;DR: Sina no study reports systematically colkctcd muscle liber length in all lower limb muscles, including hip muscles, so the following work is conducted.

544 citations


"Architectural and functional featur..." refers background in this paper

  • ...Although it has been shown that there is marked uniformity in fiber length (4, 32) and fascicle length (4, 24) throughout a muscle, some studies have reported heterogeneity of fascicle angles (24) and even fascicle lengths (11, 21) along the length of the muscle....

    [...]

  • ...The triceps surae muscles are the main synergists for plantar flexion (6, 18), but they have different architectural properties, such as muscle length, fascicle length, and pennation angles (3, 4, 32)....

    [...]

  • ...Attempts have been made to determine the geometric arrangement of muscle fibers or fascicles (muscle architecture) in humans, and many attemtps have been based on measurements of cadaver specimens (3, 4, 11, 12, 29, 32)....

    [...]

  • ...In many cases, when investigators refer to muscle fiber length, they are actually referring to fascicle length (4, 11, 12, 24, 25, 29), although some muscle fibers have been shown to terminate midfascicularly (17, 31)....

    [...]

  • ...Furthermore, many of the previous reports have been based on cadaver specimens (3, 4, 11, 12, 29, 32), and little data are available on muscle architecture in living human muscles, especially during contraction....

    [...]