Should tendon and aponeurosis be considered in series?

Epstein, Marcelo; Wong, Max; Herzog, Walter

doi:10.1016/j.jbiomech.2005.06.011

Cited by 53 publications

(55 citation statements)

References 5 publications

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“…The arrangement of passive elastic structures with respect to the contractile apparatus is complex and unlikely to be of a strictly 'inseries' nature (Epstein et al, 2006). Accordingly, our estimate of mean SEE stiffness may not have encapsulated the stiffening and rearrangement of all passive force-transmitting structures.…”

Section: Discussionmentioning

confidence: 91%

Effects of series elastic compliance on muscle force summation and the rate of force rise

Mayfield

Cresswell

Lichtwark

2016

Journal of Experimental Biology

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Compliant tendons permit mechanically unfavourable fascicle dynamics during fixed-end contractions. The purpose of this study was to reduce the effective compliance of tendon and investigate how small reductions in active shortening affect twitch kinetics and contractile performance in response to a second stimulus. The series elastic element (SEE) of the human triceps surae (N=15) was effectively stiffened by applying a 55 ms rotation to the ankle, through a range of 5 deg, at the onset of twitch and doublet [interstimulus interval (ISI) of 80 ms] stimulation. Ultrasonography was employed to quantify lateral gastrocnemius and soleus fascicle lengths. Rotation increased twitch torque (40-75%), rate of torque development (RTD; 124-154%) and torque-time integral (TTI; 70-110%) relative to constant-length contractions at the initial and final joint positions, yet caused only modest reductions in shortening amplitude and velocity. The torque contribution of the second pulse increased when stimulation was preceded by rotation, a finding unable to be explained on the basis of fascicle length or SEE stiffness during contraction post-rotation. A further increase in torque contribution was not demonstrated, nor was an increase in doublet TTI, when the second pulse was delivered during rotation and shortly after the initial pulse (ISI of 10 ms). The depressant effect of active shortening on subsequent torque generation suggests that compliant tendons, by affording large length changes, may limit torque summation. Our findings indicate that changes in tendon compliance shown to occur in response to resistance training or unloading are likely sufficient to considerably alter contractile performance, particularly maximal RTD.

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Section: Discussionmentioning

confidence: 91%

Effects of series elastic compliance on muscle force summation and the rate of force rise

Mayfield

Cresswell

Lichtwark

2016

Journal of Experimental Biology

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“…Tension is not distributed uniformly in the extramuscular and intramuscular parts of the tendon, nor is it distributed uniformly in muscle fascicles and intramuscular tendon (Epstein et al, 2006). Thus, the length-tension curves do not show the relationship between the length of each element (muscle fascicles or tendons) and the tension in that element.…”

Section: Discussionmentioning

confidence: 92%

Passive mechanical properties of human gastrocnemius muscle–tendon units, muscle fascicles and tendonsin vivo

Hoang

Herbert

Todd

et al. 2007

Journal of Experimental Biology

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SUMMARY This study provides the first in vivo measures of the passive length–tension properties of relaxed human muscle fascicles and their tendons. A new method was used to derive passive length–tension properties of human gastrocnemius muscle–tendon units from measures of ankle stiffness obtained at a range of knee angles. Passive length–tension curves of the muscle–tendon unit were then combined with ultrasonographic measures of muscle fascicle length and pennation to determine passive length–tension curves of the muscle fascicles and tendons. Mean slack lengths of the fascicles, tendons and whole muscle–tendon units were 3.3±0.5 cm, 39.5±1.6 cm and 42.3±1.5 cm, respectively (means ± s.d., N=6). On average, the muscle–tendon units were slack (i.e. their passive tension was zero) over the shortest 2.3±1.2 cm of their range. With combined changes of knee and ankle angles, the maximal increase in length of the gastrocnemius muscle–tendon unit above slack length was 6.7±1.9 cm, of which 52.4±11.7% was due to elongation of the tendon. Muscle fascicles and tendons underwent strains of 86.4±26.8% and 9.2±4.1%, respectively, across the physiological range of lengths. We conclude that the relaxed human gastrocnemius muscle–tendon unit falls slack over about one-quarter of its in vivo length and that muscle fascicle strains are much greater than tendon strains. Nonetheless, because the tendons are much longer than the muscle fascicles, tendons contribute more than half of the total compliance of the muscle–tendon unit.

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“…van Ingen Schenau et al 1997). Although there is little doubt that such an in-series arrangement exists between muscle fibers and the external tendon, the mechanics of force transmission in aponeuroses appears infinitely more complex (Epstein et al 2006). For example, Zuurbier et al (1994) reported that the aponeurosis in the rat gastrocnemius shortens with active force production, which is in complete contrast to what would happen were the aponeurosis in series with the muscle's contractile element.…”

Section: Tendon Elongation [Mm] Aponeurosis Elongation [Mm]mentioning

confidence: 99%

“…Similarly, in a theoretical study of force transmission in aponeuroses of unipennate muscles, Epstein et al (2006) showed that assuming aponeurosis to be arranged in series with the contractile elements leads to vast overestimation of energy recovery from passive muscle elements, even leading to positive work production in tendons and aponeuroses, which defies the laws of thermodynamics. A similar result was found by Chi et al (2010) who showed that small pennation angles can produce shortening in parts of the aponeuroses upon force production in unipennate muscles.…”

Section: Tendon Elongation [Mm] Aponeurosis Elongation [Mm]mentioning

confidence: 99%

Length changes of human tibialis anterior central aponeurosis during passive movements and isometric, concentric, and eccentric contractions

Tilp¹,

Steib

Herzog

2011

Eur J Appl Physiol

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The behavior of aponeuroses during voluntary contractions is still poorly understood and results provided in the literature are controversial. Therefore, the aim of this study was to investigate the behavior of the tibialis anterior aponeurosis during passive movements and active isometric, concentric, and eccentric contractions in vivo. Based on previous findings, we hypothesized that the aponeurosis exhibits behavior that is not consistent with a serial alignment with the contractile element of the muscle. Nine subjects participated in the study and performed contractions on a Biodex-dynamometer. Two ultrasound probes were used to visualize the proximal and distal ends of the tibialis anterior aponeurosis from which length changes were calculated. The main findings were that: (1) During isometric contractions, aponeurosis lengths increased and decreased with increasing and decreasing forces by about 2.8 (±1.5) mm while tendon length changes were much greater and averaged 15 (±3.3) mm, (2) during passive movements, aponeurosis lengths did not change significantly, and (3) despite similar average torque changes during concentric and eccentric contractions, aponeurosis lengths changed by 2.2 mm in concentric but only by 1.2 mm in eccentric contractions. The results of this study did not provide clear evidence for or against a serial alignment of the aponeurosis with the contractile elements. However, at low activation levels during force ramp contractions, there was a small but consistent shortening of aponeuroses with increasing torque. Our findings suggest that aponeurosis length changes do not depend on force alone but depend critically on activation level and the type of contraction.

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Should tendon and aponeurosis be considered in series?

Cited by 53 publications

References 5 publications

Effects of series elastic compliance on muscle force summation and the rate of force rise

Effects of series elastic compliance on muscle force summation and the rate of force rise

Passive mechanical properties of human gastrocnemius muscle–tendon units, muscle fascicles and tendonsin vivo

Length changes of human tibialis anterior central aponeurosis during passive movements and isometric, concentric, and eccentric contractions

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