Dynamic creep and pre-conditioning of the Achilles tendon in-vivo

Hawkins, David; Lum, C.; Gaydos, Diane; Dunning, Russell

doi:10.1016/j.jbiomech.2009.08.023

Cited by 67 publications

(62 citation statements)

References 6 publications

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“…The total scan time was ~8-12 s, which equated to an approximate average scan speed of 20 mm s −1 and hence an average distance between frames of 0.5 mm. The distance between the tendon insertion on the calcaneous and the soleus muscle-tendon junction was determined as a straight line between the most distal aspect of the notch in the calcaneous at the osteo-tendinous junction (Hawkins et al, 2009) and most distal point of the soleus muscle-tendon junction (MTJ). This length is defined as the free tendon henceforth.…”

Section: Freehand 3dus Scans and Measurementsmentioning

confidence: 99%

“…However, after the fifth contraction the net strain did not change. Similarly, low intensity (25% MVC) cyclic contractions have been shown to induce an increase in tendon strain relative to force after immobilisation; but this effect plateaued after 5 min (Hawkins et al, 2009). In contrast, when repeated isometric or isokinetic contractions are applied through the Achilles tendon after conditioning contractions, no change in tendon elongation in response to force has been found (Mademli et al, 2006), suggesting little tendon fatigue.…”

Section: Introductionmentioning

confidence: 99%

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Effects of running on human Achilles tendon length-tension properties in the free and gastrocnemius components

Lichtwark

Cresswell

Newsham-West

2013

Journal of Experimental Biology

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SUMMARYThe elastic properties of the human Achilles tendon are important for locomotion; however, in vitro tests suggest that repeated cyclic contractions lead to tendon fatigue -an increase in length in response to stress applied. In vivo experiments have not, however, demonstrated mechanical fatigue in the Achilles tendon, possibly due to the limitations of using two-dimensional ultrasound imaging to assess tendon strain. This study used freehand three-dimensional ultrasound (3DUS) to determine whether the free Achilles tendon (calcaneus to soleus) or the gastrocnemius tendon (calcaneus to gastrocnemius) demonstrated tendon fatigue after running exercise. Participants (N=9) underwent 3DUS scans of the Achilles tendon during isometric contractions at four ankle torque levels (passive, and 14, 42 and 70 N m) before and after a 5 km run at a self-selected pace (10-14 km h −1). Running had a significant main effect on the length of the free Achilles tendon (P<0.01) with a small increase in length across the torque range. However, the mean lengthening effect was small (<1%) and was not accompanied by a change in free tendon stiffness. There was no significant change in the length of the gastrocnemius tendon or the free tendon cross-sectional area. While the free tendon was shown to lengthen, the lack of change in stiffness suggests the tendon exhibited mechanical creep rather than fatigue. These effects were much smaller than those predicted from in vitro experiments, possibly due to the different loading profile encountered and the ability of the tendon to repair in vivo.

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Section: Freehand 3dus Scans and Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of running on human Achilles tendon length-tension properties in the free and gastrocnemius components

Lichtwark

Cresswell

Newsham-West

2013

Journal of Experimental Biology

View full text Add to dashboard Cite

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“…Studies using this ultrasound-based approach have focused primarily on characterizing in vivo function of the Achilles tendon, 1,2,31,37,46,50,58,61,88,90 quadriceps/patellar tendons, 34,60,78,87,97 and tibialis anterior tendons. 21,[51][52][53] Several studies, for example, have focused on characterizing strains, estimated forces, or mechanical properties in the Achilles tendon during maximum isometric contractions.…”

Section: Ultrasound Imagingmentioning

confidence: 99%

“…21,[51][52][53] Several studies, for example, have focused on characterizing strains, estimated forces, or mechanical properties in the Achilles tendon during maximum isometric contractions. 1,2,31,46,50,58,88 The effects of low-strain vs high-strain exercise protocols, 1 an 8-week strengthening program, 90 a warm-up protocol, 37 maximum isometric plantarflexion, 46 whereas Muramatsu et al 58 reported maximum Achilles tendon displacements of 4 to 16 mm, depending on torque level. In general, maximum Achilles tendon strains have been reported to be 2% to 9%.…”

Section: Ultrasound Imagingmentioning

confidence: 99%

“…In general, maximum Achilles tendon strains have been reported to be 2% to 9%. 37,58,61,90 Recently, Kim et al 41 used an ultrasound-based approach to document strains in the rotator cuff supraspinatus tendon. Ultrasound images were collected during isometric and isotonic abduction, and longitudinal strains were calculated in the superficial, middle, and deep regions of the supraspinatus tendon with an automated tracking technique.…”

Section: Ultrasound Imagingmentioning

confidence: 99%

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Measurement of in vivo tendon function

Bey

Derwin

2012

Journal of Shoulder and Elbow Surgery

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Engineering hybrid textile braids for tendon and ligament repair application

Peixoto

Carneiro

Fangueiro

et al. 2021

J of Applied Polymer Sci

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Challenges involving tendon and ligament repair have motivated the investigation of new strategies to improve clinical outcomes. These have been mainly based on polymer constructs, which may be non-biodegradable or biodegradable. The former typically fails due to lack of device integration and the latter demands a complex balance between biodegradability and tissue ingrowth, often failing due to insufficient mechanical properties. This work presents the development of hybrid braids based on polyethylene terephthalate (PET) and polylactic acid (PLA) yarns. A textile technique was used to fabricate braids based on 16 multifilament yarns of varying PLA/PET composition. The composition was varied to maximize biodegradability while ensuring mechanical performance. The braids' morphology, physical and mechanical properties were characterized. As production parameters and architecture were maintained, the braids exhibited similar porosity and wicking ability. The breaking force and stiffness decreased significantly as the number of PLA yarns increased, although strain levels remained constant. Braids containing 10 and 12 PET yarns (out of the total 16 yarns) demonstrated good creep and force-relaxation behavior, as well as resistance to cyclic loading. These compositions were selected for future work, to be assembled into more elaborate structures to mimic the fibrous organization and tensile properties of different tendons/ ligaments.

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Dynamic creep and pre-conditioning of the Achilles tendon in-vivo

Cited by 67 publications

References 6 publications

Effects of running on human Achilles tendon length-tension properties in the free and gastrocnemius components

Effects of running on human Achilles tendon length-tension properties in the free and gastrocnemius components

Measurement of in vivo tendon function

Engineering hybrid textile braids for tendon and ligament repair application

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