Relationship Between Achilles Tendon Mechanical Properties and Gastrocnemius Muscle Function

1993 ◽  
Vol 115 (3) ◽  
pp. 225-230 ◽  
Author(s):  
C. L. Trestik ◽  
R. L. Lieber

Strain was measured along the length of frog (Rana pipiens) gastrocnemius muscle-tendon units (MTU). Maximum muscle tension (P0) was measured, and the MTU was passively loaded to P0. Strain at P0 was measured at eight intervals along the tendon and aponeurosis and was approximately two percent for all regions except the aponeurosis region closest to the muscle fibers where it was about six percent. A computer model predicted sarcomere shortening of up to 0.5 μm due to tendon lengthening which demonstrates that tendons provide a more complex physiological function than simply transmitting muscle force to bones.

2001 ◽  
Vol 90 (5) ◽  
pp. 1671-1678 ◽  
Author(s):  
Tadashi Muramatsu ◽  
Tetsuro Muraoka ◽  
Daisuke Takeshita ◽  
Yasuo Kawakami ◽  
Yuichi Hirano ◽  
...  

Load-strain characteristics of tendinous tissues (Achilles tendon and aponeurosis) were determined in vivo for human medial gastrocnemius (MG) muscle. Seven male subjects exerted isometric plantar flexion torque while the elongation of tendinous tissues of MG was determined from the tendinous movements by using ultrasonography. The maximal strain of the Achilles tendon and aponeurosis, estimated separately from the elongation data, was 5.1 ± 1.1 and 5.9 ± 1.6%, respectively. There was no significant difference in strain between the Achilles tendon and aponeurosis. In addition, no significant difference in strain was observed between the proximal and distal regions of the aponeurosis. The results indicate that tendinous tissues of the MG are homogenously stretched along their lengths by muscle contraction, which has functional implications for the operation of the human MG muscle-tendon unit in vivo.


2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Yangjing Lin ◽  
Jin Cao ◽  
Changgui Zhang ◽  
Liu Yang ◽  
Xiaojun Duan

Background. Both percutaneous Achilles tendon lengthening by triple hemisection and the traditional open Z-lengthening are effective methods for Achilles tendon contracture. This study aims to evaluate the efficacy and safety of this new therapeutic method, which is based on the percutaneous sliding technique with three hemi-cuts in the tendon, as compared with the traditional open Z-lengthening. Methods. Retrospective analysis of the Achilles tendon contracture cases in our hospital between January 2010 and September 2016 was conducted. Twenty-five cases received percutaneous Achilles tendon lengthening (group A), and 30 patients who underwent open Z-lengthening during the same period were in the control group (group B). Operative time and hospital stay were statistically analyzed. Incision complication, equinus recurrence rate and Achilles tendon rupture morbidity were recorded. The function was assessed by American Orthopaedic Foot & Ankle Society (AOFAS) score. All cases in group A received Magnetic Resonance Imaging (MRI) of ankle preoperatively and in the follow-ups. Results. The mean follow-up period was 42.04 months in group A and 61.7 months in group B. The entire operative time and the mean hospitalization days were lower in group A than in group B. No incision and infection complication occurred in group A. The infection rate in group B was 3.3%. Equinus recurrence rate was 4% in group A and the equinus recurrence rate in group B was 21.4%. In group A, the mean AOFAS score increased from 64 ± 10.16 points preoperatively to 96.08 ± 3.17 at final follow-up, while the score in group B increased from 63.48 ± 6.2 points to 85.4 ± 10.3. MRI showed continuity of the Achilles tendon and homogeneous signal in group A. Conclusion. Modified surgery can significantly reduce the risk of Achilles tendon rupture, provide better balance in soft tissue strength between ankle dorsiflexion and ankle plantarflexion, helping to avoid recurrence of the deformity.


Life ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 569
Author(s):  
Liqin Deng ◽  
Xini Zhang ◽  
Songlin Xiao ◽  
Baofeng Wang ◽  
Weijie Fu

This study aims to explore whether gender differences exist in the architectural and mechanical properties of the medial gastrocnemius–Achilles tendon unit (gMTU) in vivo. Thirty-six healthy male and female adults without training experience and regular exercise habits were recruited. The architectural and mechanical properties of the gMTU were measured via an ultrasonography system and MyotonPRO, respectively. Independent t-tests were utilized to quantify the gender difference in the architectural and mechanical properties of the gMTU. In terms of architectural properties, the medial gastrocnemius (MG)’s pennation angle and thickness were greater in males than in females, whereas no substantial gender difference was observed in the MG’s fascicle length; the males possessed Achilles tendons (ATs) with a longer length and a greater cross-sectional area than females. In terms of mechanical properties, the MG’s vertical stiffness was lower and the MG’s logarithmic decrement was greater in females than in males. Both genders had no remarkable difference in the AT’s vertical stiffness and logarithmic decrement. Gender differences of individuals without training experience and regular exercise habits exist in the architectural and mechanical properties of the gMTU in vivo. The MG’s force-producing capacities, ankle torque, mechanical efficiency and peak power were higher in males than in females. The load-resisting capacities of AT were greater and the MG strain was lesser in males than in females. These findings suggest that males have better physical fitness, speed and performance in power-based sports events than females from the perspective of morphology and biomechanics.


2009 ◽  
Vol 106 (4) ◽  
pp. 1249-1256 ◽  
Author(s):  
Anthony D. Kay ◽  
Anthony J. Blazevich

The effects of static stretch on muscle and tendon mechanical properties and muscle activation were studied in fifteen healthy human volunteers. Peak active and passive moment data were recorded during plantar flexion trials on an isokinetic dynamometer. Electromyography (EMG) monitoring of the triceps surae muscles, real-time motion analysis of the lower leg, and ultrasound imaging of the Achilles-medial gastrocnemius muscle-tendon junction were simultaneously conducted. Subjects performed three 60-s static stretches before being retested 2 min and 30 min poststretch. There were three main findings in the present study. First, peak concentric moment was significantly reduced after stretch; 60% of the deficit recovered 30 min poststretch. This was accompanied by, and correlated with ( r = 0.81 ; P < 0.01) reductions in peak triceps surae EMG amplitude, which was fully recovered at 30 min poststretch. Second, Achilles tendon length was significantly shorter during the concentric contraction after stretch and at 30 min poststretch; however, no change in tendon stiffness was detected. Third, passive joint moment was significantly reduced after stretch, and this was accompanied by significant reductions in medial gastrocnemius passive muscle stiffness; both measures fully recovered by 30 min poststretch. These data indicate that the stretching protocol used in this study induced losses in concentric moment that were accompanied by, and related to, reductions in neuromuscular activity, but they were not associated with alterations in tendon stiffness or shorter muscle operating length. Reductions in passive moment were associated with reductions in muscle stiffness, whereas tendon mechanics were unaffected by the stretch. Importantly, the impact on mechanical properties and neuromuscular activity was minimal at 30 min poststretch.


2021 ◽  
Vol 120 ◽  
pp. 110384
Author(s):  
Sujata Khandare ◽  
Molly Smallcomb ◽  
Bailey Klein ◽  
Colby Geary ◽  
Julianna C. Simon ◽  
...  

1996 ◽  
Vol 271 (2) ◽  
pp. C563-C570 ◽  
Author(s):  
G. J. Lutz ◽  
L. C. Rome

We determined the influence of temperature on muscle function during jumping to better understand how the frog muscular system is designed to generate a high level of mechanical power. Maximal jumping performance and the in vivo operating conditions of the semimembranosus muscle (SM), a hip extensor, were measured and related to the mechanical properties of the isolated SM in the accompanying paper [Muscle function during jumping in frogs. II. Mechanical properties of muscle: implication for system design. Am. J. Physiol. 271 (Cell Physiol. 40): C571-C578, 1996]. Reducing temperature from 25 to 15 degrees C caused a 1.75-fold decline in peak mechanical power generation and a proportional decline in aerial jump distance. The hip and knee joint excursions were nearly the same at both temperatures. Accordingly, sarcomeres shortened over the same range (2.4 to 1.9 microns) at both temperatures, corresponding to myofilament overlap at least 90% of maximal. At the low temperature, however, movements were made more slowly. Angular velocities were 1.2- to 1.4-fold lower, and ground contact time was increased by 1.33-fold at 15 degrees C. Average shortening velocity of the SM was only 1.2-fold lower at 15 degrees C than at 25 degrees C. The low Q10 of velocity is in agreement with that predicted for muscles shortening against an inertial load.


Author(s):  
Xini Zhang ◽  
Liqin Deng ◽  
Songlin Xiao ◽  
Lu Li ◽  
Weijie Fu

Background: Patients with Achilles tendon (AT) injuries are often engaged in sedentary work because of decreasing tendon vascularisation. Furthermore, men are more likely to be exposed to AT tendinosis or ruptures. These conditions are related to the morphological and mechanical properties of AT, but the mechanism remains unclear. This study aimed to investigate the effects of sex on the morphological and mechanical properties of the AT in inactive individuals. Methods: In total, 30 inactive healthy participants (15 male participants and 15 female participants) were recruited. The AT morphological properties (cross-sectional area, thickness, and length) were captured by using an ultrasound device. The AT force–elongation characteristics were determined during isometric plantarflexion with the ultrasonic videos. The AT stiffness was determined at 50%–100% maximum voluntary contraction force. The AT strain, stress, and hysteresis were calculated. Results: Male participants had 15% longer AT length, 31% larger AT cross-sectional area and 21% thicker AT than female participants (p < 0.05). The plantarflexion torque, peak AT force, peak AT stress, and AT stiffness were significantly greater in male participants than in female participants (p < 0.05). However, no significant sex-specific differences were observed in peak AT strain and hysteresis (p > 0.05). Conclusions: In physically inactive adults, the morphological properties of AT were superior in men but were exposed to higher stress conditions. Moreover, no significant sex-specific differences were observed in peak AT strain and hysteresis, indicating that the AT of males did not store and return elastic energy more efficiently than that of females. Thus, the mechanical properties of the AT should be maintained and/or improved through physical exercise.


2021 ◽  
Vol 6 (4) ◽  
pp. 247301142110505
Author(s):  
Justin C. Haghverdian ◽  
Christopher E. Gross ◽  
Andrew R. Hsu

Chronic Achilles tendon ruptures can result in tendon lengthening and significant functional deficits including gait abnormalities and diminished push-off strength. Surgical intervention is typically required to restore Achilles tension and improve ankle plantarflexion strength. A variety of surgical reconstruction techniques exist depending on the size of the defect and amount of associated tendinosis. For smaller tendon defects 2 to 3 cm in size, primary end-to-end repair using an open incision and multiple locking sutures is an established technique. However, a longer skin incision and increased soft tissue dissection is required, and failure at the suture-tendon interface has been reported that can result in postoperative tendon elongation and persistent weakness. In this report, we describe a novel technique to reconstruct chronic midsubstance Achilles tendon ruptures using a small incision with knotless repair of the tendon secured directly to the calcaneus. This technique minimizes wound healing complications, increases construct fixation strength, and allows for early range of motion and rehabilitation. Level of Evidence: Level V, Expert Opinion.


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