A comparison of knee extensor strength curves obtained theoretically and experimentally

Hasler, E.M.; Abrahamse, Sheila K.

doi:10.1249/00005768-199101000-00016

Cited by 35 publications

(29 citation statements)

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“…Additionally, the lumped parameter muscle model assumes that all fibres within a muscle operate at the same length. The fibres of these muscles may be distributed over a range of lengths [15,[55][56][57]. In this case, the fibres within a muscle may occupy different regions of the force-length curve or operate at varying velocities.…”

Section: Discussionmentioning

confidence: 99%

“…force-velocity effects and musculotendon compliance). Other studies have estimated fibre or fascicle lengths over a range of motion for a single joint [12][13][14][15][16][17][18] or during a movement [19] using imaging technology or mathematical modelling. Fukunaga et al [19], for example, used ultrasound measurements to examine muscle fascicle lengths and tendon lengths of medial gastrocnemius.…”

Section: Introductionmentioning

confidence: 99%

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Fibre operating lengths of human lower limb muscles during walking

Arnold

Delp

2011

Phil. Trans. R. Soc. B

111

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Muscles actuate movement by generating forces. The forces generated by muscles are highly dependent on their fibre lengths, yet it is difficult to measure the lengths over which muscle fibres operate during movement. We combined experimental measurements of joint angles and muscle activation patterns during walking with a musculoskeletal model that captures the relationships between muscle fibre lengths, joint angles and muscle activations for muscles of the lower limb. We used this musculoskeletal model to produce a simulation of muscle-tendon dynamics during walking and calculated fibre operating lengths (i.e. the length of muscle fibres relative to their optimal fibre length) for 17 lower limb muscles. Our results indicate that when musculotendon compliance is low, the muscle fibre operating length is determined predominantly by the joint angles and muscle moment arms. If musculotendon compliance is high, muscle fibre operating length is more dependent on activation level and force-length -velocity effects. We found that muscles operate on multiple limbs of the force -length curve (i.e. ascending, plateau and descending limbs) during the gait cycle, but are active within a smaller portion of their total operating range.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fibre operating lengths of human lower limb muscles during walking

Arnold

Delp

2011

Phil. Trans. R. Soc. B

111

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“…This suggests that the working ranges (widths) of the force-length relationship of the Vastii are similar for old and young adults. Consequently, the observed age-related differences in muscle strength of the Vastii would be reduced at short fascicle lengths (extended knee joint) because of the parabolic curve of the force-length relationship of the Vastii (Herzog et al, 1991). (3) Finally, the age-related patterns observed for the knee extension moment at different joint angle configurations might be caused by a modulation of the EMGactivity.…”

Section: Lower Extremity Muscle-tendon Unit Propertiesmentioning

confidence: 99%

Mechanical and morphological properties of different muscle–tendon units in the lower extremity and running mechanics: effect of aging and physical activity

Karamanidis

Arampatzis

2005

Journal of Experimental Biology

130

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SUMMARY The objectives of this work were (i) to investigate whether chronic endurance running is a sufficient stimulus to counteract the age-related changes in the mechanical and morphological properties of human triceps surae(TS) and quadriceps femoris (QF) muscle–tendon units (MTUs) by comparing runners and non-active subjects at different ages (young and old), (ii) to identify adaptational phenomena in running mechanics due to age-related changes in the mechanical and morphological properties of the TS and QF MTUs,and finally (iii) to examine whether chronic endurance-running exercise is associated with adaptational effects on running characteristics in old and young adults. The investigation was conducted on 30 old and 19 young adult males divided into two subgroups according to their running activity: endurance-runners vs non-active. To analyse the properties of the MTUs, all subjects performed isometric maximal voluntary (MVC) ankle plantarflexion and knee extension contractions at 11 different MTU lengths on a dynamometer. The activation of the TS and QF during MVC was estimated by surface electromyography. The gastrocnemius medialis and the vastus lateralis and their distal aponeuroses were visualized by ultrasonography at rest and during MVC, respectively. Ground reaction forces and kinematic data were recorded during running trials at 2.7 m s–1. The TS and QF MTU capacities were reduced with aging (lower muscle strength and lower tendon stiffness). Runners and non-active subjects had similar MTU properties, suggesting that chronic endurance-running exercise does not counteract the age-related degeneration of the MTUs. Runners showed a higher mechanical advantage for the QF MTU while running (lower gear ratio) compared to non-active subjects, indicating a task-specific adaptation even at old age. Older adults reacted to the reduced capacities of their MTUs by increasing running safety (higher duty factor, lower flight time) and benefitting from a mechanical advantage for the TS MTU, lower rate of force generation and force generation per meter distance. We suggest that the improvement in running mechanics in the older adults happens due to a perceptual motor recalibration and a feed-forward adaptation of the motor task aimed at decreasing the disparity between the reduced capacity of the MTUs and the running effort.

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“…The reliability of this device is documented elsewhere (Tredinnick & Duncan, 1988). The experimental protocol was similar to the one used by Herzog, Hasler, and Abrahamse (1991). The warm-up consisted of a series of submaximal dynamic contractions on the dynamometer, two stretch exercises, and three submaximal isometric contractions.…”

Section: Subjects and Experimental Protocolmentioning

confidence: 99%

“…The subjects were asked to gradually build up to a maximal contraction and to maintain this for at least 1 s to ensure that the contraction was truly isometric (i.e., that muscle moment and thus muscle fiber length were more or less constant) (Herzog, Hasler, & Abrahamse, 1991). At each knee angle, the passive moment was measured at rest, and the maximum voluntary moment was determined by averaging the moment over the plateau phase.…”

Section: Subjects and Experimental Protocolmentioning

confidence: 99%

The Isometric Knee Extension Moment-Angle Relationship: Experimental Data and Predictions Based on Cadaver Data

Meijer¹,

Bosch²,

Bobbert³

et al. 1998

Journal of Applied Biomechanics

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The influence of parameter values (i.e., fiber optimum lengths and moment arms) and simplification of the geometry of a Hill-type muscle model on the prediction of normalized maximal isometric knee extension moment to knee joint angle relationship was studied. For that purpose, the geometry of m. quadriceps femoris was modeled in considerable detail, and all parameter values were determined on one set of cadaver specimens that had been selected for muscular appearance. The predicted relationship was compared to that measured in human subjects over the full range of physiological knee angles, and a good correspondence was found (r = .96). The good correspondence could be attributed to the substitution of realistic parameter values into the model. Incorporating complex muscle geometry into the model resulted in a small additional improvement of the prediction. It was speculated that the variation in results of cadaver measurements among studies reflects true differences caused by individuals' levels of physical activity in the period preceding death.Key Words: m. quadriceps femoris, muscle model, geometry, human cadavers Insight into the factors determining performance of motor tasks will benefit practitioners in athletics and rehabilitation. It is generally recognized that performance depends on properties of the musculoskeletal system and on control, with the effects of control being determined by the stimulation patterns that the nervous system sends to the muscles. In order to gain insight into the importance of system properties and control, it is necessary to systematically manipulate these factors and monitor the effects on performance. Unfortunately, system properties cannot be changed in living subjects for obvious reasons, and subjects are unable to systematically manipulate their control. For that reason, researchers have turned to models of the neuromusculoskeletal system. These models may be constructed such that the input consists of muscle stimulation patterns and the output is the movement and therewith the performance on the task (Levine,

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A comparison of knee extensor strength curves obtained theoretically and experimentally

Cited by 35 publications

References 0 publications

Fibre operating lengths of human lower limb muscles during walking

Fibre operating lengths of human lower limb muscles during walking

Mechanical and morphological properties of different muscle–tendon units in the lower extremity and running mechanics: effect of aging and physical activity

The Isometric Knee Extension Moment-Angle Relationship: Experimental Data and Predictions Based on Cadaver Data

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