Method and strain rate dependence of Achilles tendon stiffness

Theis, Nicola; Mohagheghi, Amir A.; Korff, Thomas

doi:10.1016/j.jelekin.2012.06.004

Cited by 31 publications

(28 citation statements)

References 28 publications

(48 reference statements)

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“…The current study found a difference in strain (1.2%) between participants with IAT and controls that was similar in magnitude to that of previous studies comparing participants with midportion Achilles tendinopathy to controls (Arya and Kulig, 5 0.8%; Child et al, 8 1.8%). Methodological differences, such as a passive or active task, 32 range of ankle excursion, 18 and determining the tendon length, 7 can affect values when comparing across studies. For example, it would be anticipated that during an isometric contraction, as performed in the studies of Arya and Kulig 5 and Child et al, 8 the strain would be greater than during a passive task, 32 as performed in the current study.…”

Section: Discussionmentioning

confidence: 99%

“…Methodological differences, such as a passive or active task, 32 range of ankle excursion, 18 and determining the tendon length, 7 can affect values when comparing across studies. For example, it would be anticipated that during an isometric contraction, as performed in the studies of Arya and Kulig 5 and Child et al, 8 the strain would be greater than during a passive task, 32 as performed in the current study. Nonetheless, the similar group effects across different methodologies and types of Achilles tendinopathy support the idea that tendon strain is increased in this population.…”

Section: Discussionmentioning

confidence: 99%

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Altered Tendon Characteristics and Mechanical Properties Associated With Insertional Achilles Tendinopathy

Chimenti¹,

Flemister²,

Tome³

et al. 2014

J Orthop Sports Phys Ther

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A cross-sectional image was obtained 2 cm proximal to the tendon insertion. Echogenicity was quantified as the mean grayscale value for the central 1 cm of the entire depth of the tendon cross-section (FIGURES 1C and 1D). The grayscale value for a pixel could range from 0 (black) to 255 (white). The mean grayscale value for all pixels in the region of interest was quantified using ImageJ, with a lower value indicating greater pathology. All ultrasound images had the same gain setting of 56 and were collected at a 3-cm depth, so that differences in ultrasound settings would not influence the mean grayscale values between participants. Tendon Mechanical PropertiesThe combination of ultrasound imaging and dynamometry was used to measure tendon mechanical properties (strain, stiffness). Each participant's ankle was positioned and secured in a Biodex System 4 (Biodex Medical Systems, Inc, Shirley, NY) in sitting, with the seatback reclined to 45°, the chair height adjusted so that the tibia was parallel to the floor, and the hip in neutral adduction/abduction (FIGURE 2A). The participant's ankle was moved in the sagittal plane from 10° of plantar flexion to 10° of dorsiflexion at a rate of 5°/s, and the passive plantar flexion torque was recorded at a rate of 1000 Hz. Similar to previous studies, 5,8,18 ultrasound imaging was used to track the linear displacement of the gastrocnemius muscle-Achilles tendon junction (MTJ), with the probe at a fixed point on the calf (FIGURES 2B and 2C). A first set of 6 rotations was used for preconditioning, followed by a second set of 6 rotations, from which images were used to calculate tendon mechanical properties. B-mode ultrasound images were collected when the ankle was in (1) 10° of plantar flexion at the start and end of the second set and (2) 10° of dorsiflexion during the third, fourth, and fifth repetitions. The location of the MTJ in each ankle position was averaged, so that distance between the MTJ locations in 10° of plantar flexion and 10° of dorsiflexion could be calculated. A video was taken on the second repetition to confirm that the images captured the full range of MTJ displacement. Passive torque values from the third, fourth, and fifth repetitions of the second set were used for analysis. Participants were instructed to relax as the foot plate moved the ankle. To ensure that the condition was passive, the activity of the medial gastrocnemius and the anterior tibialis muscles was monitored by a 2-channel Bagnoli desktop electromyography system (Delsys Inc, Natick, MA). Single-differential surface electrodes (input impedance greater than 1015 Ω // 0.2 pF; common-mode rejection ratio, -92 dB; noise, 1.2 μV; preamplifier gain, 10 V/V  1%) were used. The contact material was 99.9% Ag, in the shape of 2 bars with contact dimensions of 10 × 1 mm and spaced 1 cm apart. The electrodes were placed over the motor point of the medial gastrocnemius and the anterior tibialis muscles. The raw electromyography signal was viewed using a 2-channel digitizing oscilloscope (Tektr...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Altered Tendon Characteristics and Mechanical Properties Associated With Insertional Achilles Tendinopathy

Chimenti¹,

Flemister²,

Tome³

et al. 2014

J Orthop Sports Phys Ther

View full text Add to dashboard Cite

show abstract

“…Nonetheless, RFD also remained unchanged, indicating that changes in tendon stiffness of the magnitude elicited by the current training (ϳ29%) were not sufficient to affect RFD, which left little rationale for further exploring the relationship between changes in RFD and changes in tendon stiffness. The fact that RFD remained unchanged also negated the need to adjust tendon stiffness estimates for changes in force application, which may have increased with loading rate due to the tendon's rate-dependent properties (49,59). It should be noted, however, that the relationship reported previously (63) was demonstrated over a broad range of tendon stiffness values (ϳ500% difference in tendon stiffness between the least and most stiff children).…”

mentioning

confidence: 86%

Effects of resistance training on tendon mechanical properties and rapid force production in prepubertal children

Waugh

Korff

Fath

et al. 2014

Journal of Applied Physiology

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Children develop lower levels of muscle force, and at slower rates, than adults. Although strength training in children is expected to reduce this differential, a synchronous adaptation in the tendon must be achieved to ensure forces continue to be transmitted to the skeleton with efficiency while minimizing the risk of strain-related tendon injury. We hypothesized that resistance training (RT) would alter tendon mechanical properties in children concomitantly with changes in force production characteristics. Twenty prepubertal children (age 8.9 ± 0.3 yr) were equally divided into control (nontraining) and experimental (training) groups. The training group completed a 10-wk RT intervention consisting of 2-3 sets of 8-15 plantar flexion contractions performed twice weekly on a recumbent calf-raise machine. Achilles tendon properties (cross-sectional area, elongation, stress, strain, stiffness, and Young's modulus), electromechanical delay (EMD; time between the onset of muscle activity and force), rate of force development (RFD; slope of the force-time curve), and rate of electromyographic (EMG) increase (REI; slope of the EMG time curve) were measured before and after RT. Tendon stiffness and Young's modulus increased significantly after RT in the experimental group only (∼29% and ∼25%, respectively); all other tendon properties were not significantly altered, although there were mean decreases in both peak tendon strain and strain at a given force level (14% and 24%, respectively; not significant) which may have implications for tendon injury risk and muscle fiber mechanics. A decrease of ∼13% in EMD was found after RT for the experimental group, which paralleled the increase in tendon stiffness (r = -0.59); however, RFD and REI were unchanged. The present data show that the Achilles tendon adapts to RT in prepubertal children and is paralleled by a change in EMD, although the magnitude of this change did not appear to be sufficient to influence RFD. These findings are of importance within the context of the efficiency and execution of movement.

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“…Muscle-tendon mechanical configuration depends on the dynamics between the produced force and compliance of the series elastic component (SEC; Narici et al 1996;Reeves & Narici 2003). SEC stiffness is dependent on the applied force magnitude and velocity (Fukunaga et al 1997;Pearson et al 2007;Theis et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Effects of muscle action type on corticospinal excitability and triceps surae muscle-tendon mechanics

Valadão

Kurokawa

Finni

et al. 2018

Journal of Neurophysiology

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Valadão, Pedro Frederico, 2012. Effects of muscle action type on corticospinal excitability and triceps surae muscle-tendon mechanics. Department of Biology of Physical Activity, University of Jyväskylä. Master's Thesis in Biomechanics. 105 pp.The present study was designed to investigate corticospinal excitability modulation during maximum isometric and eccentric muscle actions with two different velocities. Moreover, the study aimed to clarify the effect of muscle action type on muscle-tendon mechanical behavior in order to shed light into the possible role of sensory information in modulating corticospinal excitability during different muscle actions. We compared motor evoked potentials (MEPs) to transcranial magnetic stimulation and Hoffman reflexes (H-reflex) in soleus muscle during isometric, slow eccentric (25 deg/s) and fast eccentric (100 deg/s) muscle actions. Concomitantly, ultrasonography was utilized to access soleus and medial gastrocnemius fascicle behavior, characterized by fascicle length, velocity and pennation angle.The main finding was that soleus H-reflex was depressed (P < 0.001) during both fast and slow eccentric protocols as compared to isometric, while no differences in fascicle length (P = 0.569) and pennation angle (P = 0.293) were found among the three protocols.Furthermore, although the fast eccentric protocol had a greater fascicle velocity than slow eccentric (P < 0.05), there were no differences in H-reflex (P > 0.05). No differences in MEP sizes were found among the three protocols (P = 0.750), while absolute silent period was significantly shorter (P = 0.009) for both eccentric protocols as compared to isometric.Taken together, the present results corroborates with the idea that the central nervous system has an unique activation strategy during eccentric muscle actions , Enoka 1996, and further refutes the hypothesis that sensory information plays an important role in modulating these actions.

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Method and strain rate dependence of Achilles tendon stiffness

Cited by 31 publications

References 28 publications

Altered Tendon Characteristics and Mechanical Properties Associated With Insertional Achilles Tendinopathy

Altered Tendon Characteristics and Mechanical Properties Associated With Insertional Achilles Tendinopathy

Effects of resistance training on tendon mechanical properties and rapid force production in prepubertal children

Effects of muscle action type on corticospinal excitability and triceps surae muscle-tendon mechanics

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