A Simplified Method for Considering Achilles Tendon Curvature in the Assessment of Tendon Elongation

Kharazi, Mohamadreza; Theodorakis, Christos; Mersmann, Falk; Arampatzis, Adamantios; Böhm, Sebastian

doi:10.3390/s21217387

Cited by 2 publications

(1 citation statement)

References 29 publications

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“…However, in this study, the free tendon was measured as a straight line, which could have affected the accuracy of the results. Kharazi et al found that Achilles tendons measured using a straight line underestimated the length by 0.1 to 4.3 mm during the walking gait cycle [ 50 ] Since this straight-line technique was used for all patients, both cases and controls, the comparison of the free tendon lengths is justifiable. There was no significant difference in tibiotalar angle between the two groups ( Table 1 ).…”

Section: Discussionmentioning

confidence: 99%

The Distal Free Achilles Tendon Is Longer in People with Tendinopathy than in Controls: A Retrospective Case-Control Study

Callow

Cresswell

Damji

et al. 2022

Translational Sports Medicine

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Objectives. The free Achilles tendon is defined as the region of tendon distal to the soleus which is “unbuttressed,” i.e., unsupported by muscular tissue. We reasoned that a relative lack of distal buttressing could place the tendon at a greater risk for developing Achilles tendinopathy. Therefore, our primary goal was to compare the free Achilles tendon length between those with midportion or insertional Achilles tendinopathy and healthy controls. Design. This is a retrospective case-control study. Setting. Hospital in Vancouver, Canada. Participants. 66 cases with Achilles tendinopathy (25 insertional, 41 midportion) consecutively drawn from a hospital database within a 5-year period and matched to 66 controls (without tendinopathy) based on sex, age, and weight. Main outcome measures. Odds ratio of the risk of developing Achilles tendinopathy given the length of free tendon, defined anatomically on MRI, after adjustment for confounders. Results. MRI-defined free Achilles tendon length is a statistically significant predictor of having midportion Achilles tendinopathy (odds ratio = 0.53, 95% confidence interval 1.13 to 2.07). Midportion Achilles tendinopathy cases had significantly longer free tendons (Mdn = 51.2 mm, IQR = 26.9 mm) compared to controls (Mdn = 40.8 mm, IQR = 20.0 mm), p = 0.007 . However, there was no significant difference between the free Achilles tendon lengths in insertional AT cases (Mdn = 47.9 mm, IQR = 15.1 mm) and controls (Mdn = 39.2 mm, IQR = 17.9 mm), p = 0.158 . Free Achilles tendon length was also correlated with the tendon thickness among those with Achilles tendinopathy, rτ = 0.25, and p = 0 .003 . Conclusions. The MRI-defined length of the free Achilles tendon is positively associated with the risk of midportion Achilles tendinopathy. A relative lack of distal muscular buttressing of the Achilles tendon may therefore influence the development of tendinopathy.

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Section: Discussionmentioning

confidence: 99%

The Distal Free Achilles Tendon Is Longer in People with Tendinopathy than in Controls: A Retrospective Case-Control Study

Callow

Cresswell

Damji

et al. 2022

Translational Sports Medicine

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Decoupling of muscle‐tendon unit and fascicle velocity contributes to the in vivo stretch‐shortening cycle effect in the male human triceps surae muscle

Holzer,

Hahn,

Schwirtz

et al. 2024

Physiological Reports

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During the shortening of stretch‐shortening cycles (SSCs), muscle force output is enhanced compared with pure shortening (SHO), referred to as the SSC‐effect. In general, muscle‐tendon unit (MTU), muscle belly, muscle fascicle, and tendon length changes can be decoupled during contraction, which affects force generation and elastic recoil. We researched whether MTU decoupling contributes to the SSC‐effect. Participants performed electrically stimulated submaximal fixed‐end, SSC, and SHO plantar‐flexions on a dynamometer at two velocities (40, 120°/s) and two ranges of motion (15, 25°). Fascicle and tendon length changes of the gastrocnemius medialis, and ankle joint kinematics were assessed by ultrasound and motion capture, respectively. During SSC shortening, ankle joint torque and work, MTU force and work, and fascicle force were increased by 12%–22% compared with SHO, confirming a SSC‐effect. Further, fascicle length change and velocity during SSCs were significantly reduced compared with SHO condition, and SSC fascicle work was decreased by ~35%. Our results indicate that MTU decoupling leads to a reduction in fascicle shortening amplitude and velocity, thereby increasing the muscle's force capacity while reducing its work output during SSC shortening. MTU decoupling therefore contributes to the SSC‐effect and underlines the limited transferability of joint work measurements to estimated muscle work.

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A Simplified Method for Considering Achilles Tendon Curvature in the Assessment of Tendon Elongation

Cited by 2 publications

References 29 publications

The Distal Free Achilles Tendon Is Longer in People with Tendinopathy than in Controls: A Retrospective Case-Control Study

The Distal Free Achilles Tendon Is Longer in People with Tendinopathy than in Controls: A Retrospective Case-Control Study

Decoupling of muscle‐tendon unit and fascicle velocity contributes to the in vivo stretch‐shortening cycle effect in the male human triceps surae muscle

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