scholarly journals Effect of chronic unloading and rehabilitation on human Achilles tendon properties: a velocity-encoded phase-contrast MRI study

2008 ◽  
Vol 105 (4) ◽  
pp. 1179-1186 ◽  
Author(s):  
Dongsuk Shin ◽  
Taija Finni ◽  
Sinyeob Ahn ◽  
John A. Hodgson ◽  
Hae-Dong Lee ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Muscle Strength ◽  
Achilles Tendon ◽  
Phase Contrast ◽  
Transition Point ◽  
Force Production ◽  
Triceps Surae ◽  
Cross Sectional ◽  
Triceps Surae Muscles ◽  
Mri Study

The objective of this study was to measure and monitor changes in Achilles tendon mechanical properties and force production capability of triceps surae muscles after 4 wk of limb suspension and 6 wk of physical rehabilitation. Five healthy volunteers underwent unilateral lower limb suspension followed by weekly physiotherapy. A velocity-encoded, phase-contrast magnetic resonance imaging (VE-PC-MRI) technique was used to estimate the tendon strain as a function of force produced during the submaximal isometric contractions. After limb suspension, triceps surae muscle strength decreased to 53.2 ± 15.6% (mean ± SD) of the presuspension level ( P < 0.05). Young's modulus, estimated from the slope of the tendon stress-strain relationship, decreased by 17.1% (from 140.50 ± 29.33 to 119.95 ± 36.07 MPa, P < 0.05), while the tendon transition point, reflecting the “toe region,” increased by 55.7% (from 2.2 ± 1.0% to 3.4 ± 1.24%). Muscle strength, tendon stiffness, and transition point recovered to presuspension levels by the end of 6 wk of rehabilitation. Calcaneus movement was significant during the “isometric” contraction, accounting for 52.13 ± 7.63% of the tendon displacement. Tendon cross-sectional area determined from anatomic magnetic resonance axial images remained unchanged, suggesting that the altered tendon elastic modulus and transition point were largely due to material deterioration. The increase in the transition point following chronic unloading as measured by the VE-PC-MRI technique has not been previously reported and offers new insights into the biomechanical changes that may occur in the tendon crimp structure.

scholarly journals Temperature Increases in the Human Achilles Tendon During Ultrasound Treatments With Commercial Ultrasound Gel and Full-Thickness and Half-Thickness Gel Pads

2010 ◽  
Vol 45 (4) ◽  
pp. 333-337 ◽  
Author(s):  
David O. Draper ◽  
Clinton G. Edvalson ◽  
Kenneth L. Knight ◽  
Dennis Eggett ◽  
Joseph Shurtz
Keyword(s):  
Achilles Tendon ◽  
Outcome Measure ◽  
Cross Sectional Study ◽  
Triceps Surae ◽  
Therapeutic Modality ◽  
Sectional Study ◽  
Cross Sectional ◽  
Main Outcome Measure ◽  
Internal Structures ◽  
Half Thickness

Abstract Context: Although originally manufactured for use in diagnostic imaging of internal structures, 2-cm-thick gel pads are also used as conducting media for therapeutic ultrasound over areas with bony prominences. Research on the ability of these pads to conduct enough energy to adequately heat tissues has provided mixed results. However, this research has mainly been performed on the triceps surae muscle, an area over which gel pads are not typically used. We wondered how much heating might be produced if a thinner pad was used over a tendon. Objective: To compare temperature rises in the human Achilles tendon during ultrasound treatments using ultrasound gel, a 2-cm-thick pad, and a 1-cm-thick pad. Design: Cross-sectional study. Setting: University therapeutic modality laboratory. Patients or Other Participants: Forty-eight healthy volunteers (24 women, 24 men). Intervention(s): We inserted a rigid thermocouple 1 cm deep into the Achilles tendon. Ultrasound was delivered at the following settings: 3 MHz, continuous, 1 W/cm2, 10 minutes. Main Outcome Measure(s): Temperature was recorded every 30 seconds for 10 minutes. Results: Temperature increased the most in the ultrasound gel group (increase  =  13.3°C, peak  =  42°C). The 1-cm-thick pad resulted in higher tendon temperature (increase  =  9.3°C, peak  =  37.8°C) than the 2-cm-thick pad (increase  =  6.5°C, peak  =  4.8°C). The 1-cm pad produced approximately 30% more heating than the 2-cm pad (SE  =  0.72, P &lt; .03). Conclusions: The thinner pad transmitted ultrasound more efficiently than the thicker pad. Thus, a gel pad of less than 1-cm thickness might be useful for superficial areas, such as the hands and ankles.

scholarly journals Ankle morphology amplifies calcaneus movement relative to triceps surae muscle shortening

2013 ◽  
Vol 115 (4) ◽  
pp. 468-473 ◽  
Author(s):  
R. Csapo ◽  
J. Hodgson ◽  
R. Kinugasa ◽  
V. R. Edgerton ◽  
S. Sinha
Keyword(s):  
Magnetic Resonance ◽  
Achilles Tendon ◽  
Ankle Joint ◽  
Sagittal Plane ◽  
Triceps Surae ◽  
Myotendinous Junction ◽  
Joint Movement ◽  
Center Of Rotation ◽  
Moment Arms ◽  
Plantarflexor Muscles

The present study investigated the mechanical role of the dorsoventral curvature of the Achilles tendon in the conversion of the shortening of the plantarflexor muscles into ankle joint rotation. Dynamic, sagittal-plane magnetic resonance spin-tagged images of the ankle joint were acquired in six healthy subjects during both passive and active plantarflexion movements driven by a magnetic resonance compatible servomotor-controlled foot-pedal device. Several points on these images were tracked to determine the 1) path and deformation of the Achilles tendon, 2) ankle's center of rotation, and 3) tendon moment arms. The degree of mechanical amplification of joint movement was calculated as the ratio of the displacements of the calcaneus and myotendinous junction. In plantarflexion, significant deflection of the Achilles tendon was evident in both the passive (165.7 ± 7.4°; 180° representing a straight tendon) and active trials (166.9 ± 8.8°). This bend in the dorsoventral direction acts to move the Achilles tendon closer to the ankle's center of rotation, resulting in an ∼5% reduction of moment arm length. Over the entire range of movement, the overall displacement of the calcaneus exceeded the displacement of the myotendinous junction by ∼37%, with the mechanical gains being smaller in dorsi- and larger in plantarflexed joint positions. This is the first study to assess noninvasively and in vivo using MRI the curvature of the Achilles tendon during both passive and active plantarflexion movements. The dorsoventral tendon curvature amplifies the shortening of the plantarflexor muscles, resulting in a greater displacement of the tendon's insertion into the calcaneus compared with its origin.

scholarly journals Effects of long-term athletic training on muscle morphology and tendon stiffness in preadolescence: association with jump performance

2020 ◽  
Vol 120 (12) ◽  
pp. 2715-2727
Author(s):  
Nikolaos Pentidis ◽  
Falk Mersmann ◽  
Sebastian Bohm ◽  
Erasmia Giannakou ◽  
Nickos Aggelousis ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Achilles Tendon ◽  
Muscle Hypertrophy ◽  
Muscle Thickness ◽  
Pennation Angle ◽  
Triceps Surae ◽  
Plantar Flexors ◽  
Tendon Stiffness ◽  
Jumping Performance

Abstract Purpose Evidence on training-induced muscle hypertrophy during preadolescence is limited and inconsistent. Possible associations of muscle strength and tendon stiffness with jumping performance are also not investigated. We investigated the thickness and pennation angle of the gastrocnemius medialis muscle (GM), as indicators for potential muscle hypertrophy in preadolescent athletes. Further, we examined the association of triceps surae muscle–tendon properties with jumping performance. Methods Eleven untrained children (9 years) and 21 similar-aged artistic gymnastic athletes participated in the study. Muscle thickness and pennation angle of the GM were measured at rest and muscle strength of the plantar flexors and Achilles tendon stiffness during maximum isometric contractions. Jumping height in squat (SJ) and countermovement jumps (CMJ) was examined using a force plate. We evaluated the influence of normalised muscle strength and tendon stiffness on jumping performance with a linear regression model. Results Muscle thickness and pennation angle did not differ significantly between athletes and non-athletes. In athletes, muscle strength was greater by 25% and jumping heights by 36% (SJ) and 43% (CMJ), but Achilles tendon stiffness did not differ between the two groups. The significant predictor for both jump heights was tendon stiffness in athletes and normalised muscle strength for the CMJ height in non-athletes. Conclusion Long-term artistic gymnastics training during preadolescence seems to be associated with increased muscle strength and jumping performance but not with training-induced muscle hypertrophy or altered tendon stiffness in the plantar flexors. Athletes benefit more from tendon stiffness and non-athletes more from muscle strength for increased jumping performance.

scholarly journals Depth-dependent variations in Achilles tendon deformations with age are associated with reduced plantarflexor performance during walking

2015 ◽  
Vol 119 (3) ◽  
pp. 242-249 ◽  
Author(s):  
Jason R. Franz ◽  
Darryl G. Thelen
Keyword(s):  
Achilles Tendon ◽  
Soleus Muscle ◽  
Triceps Surae ◽  
Inverse Dynamic ◽  
Joint Kinetics ◽  
Old Adults ◽  
Age Related ◽  
Dynamic Ultrasound ◽  
The Difference ◽  
Triceps Surae Muscles

The anatomical arrangement of the Achilles tendon (AT), with distinct fascicle bundles arising from the gastrocnemius and soleus muscles, may facilitate relatively independent behavior of the triceps surae muscles. A reduced capacity for sliding between adjacent tendon fascicles with age may couple gastrocnemius and soleus muscle behavior, thereby potentially contributing to diminished plantarflexor performance commonly observed in old adults. Nine healthy young (mean age, 23.9 yr) and eight healthy old (69.9 yr) adults walked at three speeds (0.75, 1.00, and 1.25 m/s) on a force-sensing treadmill. We coupled dynamic ultrasound imaging of the free AT with motion capture and inverse dynamic analyses to compute, in part: 1) depth-dependent variations in AT tissue displacements and elongations and 2) net ankle joint kinetics during push-off. The difference in displacements between superficial and deep AT regions, and in their corresponding elongations, did not differ between old and young adults at the slower two walking speeds ( P > 0.61). However, old adults walked with 41% smaller depth-dependent variations in free AT displacements and elongations at 1.25 m/s ( P = 0.02). These more uniform tendon deformations in old adults most strongly correlated with reduced peak ankle moment ( R2= 0.40), but also significantly correlated with reduced peak power generation ( R2= 0.15) and positive ankle work during push-off ( R2= 0.19) ( P > 0.01). Our findings: 1) demonstrate a potential role for nonuniform AT deformations in governing gastrocnemius and soleus muscle-tendon function and 2) allude to altered tendon behavior that may contribute to the age-related reduction in plantarflexor performance during walking.

scholarly journals Monitoring Muscle-Tendon Adaptation Over Several Years of Athletic Training and Competition in Elite Track and Field Jumpers

2020 ◽  
Vol 11 ◽  
Author(s):  
Kiros Karamanidis ◽  
Gaspar Epro
Keyword(s):  
Muscle Strength ◽  
Athletic Training ◽  
Track And Field ◽  
Triceps Surae ◽  
Overuse Injuries ◽  
Cross Sectional ◽  
Tendon Stiffness ◽  
Adaptive Changes ◽  
Tendon Strain ◽  
Over Time

Differences in muscle and tendon responsiveness to mechanical stimuli and time courses of adaptive changes may disrupt the interaction of the musculotendinous unit (MTU), increasing the risk for overuse injuries. We monitored training-induced alterations in muscle and tendon biomechanical properties in elite jumpers over 4 years of athletic training to detect potential non-synchronized adaptations within the triceps surae MTU. A combined cross-sectional and longitudinal investigation over 4 years was conducted by analyzing triceps surae MTU mechanical properties in both legs via dynamometry and ultrasonography in 67 elite track and field jumpers and 24 age-matched controls. Fluctuations in muscle and tendon adaptive changes over time were quantified by calculating individual residuals. The cosine similarity of the relative changes of muscle strength and tendon stiffness between sessions served as a measure of uniformity of adaptive changes. Our cross-sectional study was unable to detect clear non-concurrent differences in muscle strength and tendon stiffness in elite jumpers. However, when considering the longitudinal data over several years of training most of the jumpers demonstrated greater fluctuations in muscle strength and tendon stiffness and hence tendon strain compared to controls, irrespective of training period (preparation vs. competition). Moreover, two monitored athletes with chronic Achilles tendinopathy showed in their affected limb lower uniformity in MTU adaptation as well as higher fluctuations in tendon strain over time. Habitual mechanical loading can affect the MTU uniformity in elite jumpers, leading to increased mechanical demand on the tendon over an athletic season and potentially increased risk for overuse injuries.

scholarly journals Relationship Between Muscle Strength, Power and Stiffness and Running Economy in Trained Male Runners

2010 ◽  
Vol 5 (2) ◽  
pp. 249-261 ◽  
Author(s):  
Charles L. Dumke ◽  
Christopher M. Pfaffenroth ◽  
Jeffrey M. McBride ◽  
Grant O. McCauley
Keyword(s):  
Muscle Strength ◽  
Lactate Threshold ◽  
Force Production ◽  
Muscle Stiffness ◽  
Running Economy ◽  
Triceps Surae ◽  
Vo2 Max ◽  
Training Techniques ◽  
Stage 4 ◽  
Oscillation Method

Purpose:In this study, a comparison was made between muscle strength, power and muscle and tendon (km and kt respectively) stiffness of the triceps surae muscle group and running economy (RE) in trained male runners.Methods:Twelve well-trained male runners (age = 21 + 2.7 y, height = 178.1 ± 7.1 cm, body mass = 66.7 + 3.2 kg, VO2 max = 68.3 + 4.3 mLkg–1min–1, 5000-m time = 15:04 min:s) underwent passive stiffness testing using a free oscillation method. Muscle strength was determined via a maximal isometric squat test and power determined via a maximal countermovement jump (CMJ). On a separate day, subjects performed an incremental treadmill test and their RE, lactate threshold, and VO2 max were determined. Fingertip blood lactate was determined at the end of each 3-min stage. Lactate threshold was defined as a nonlinear increase in lactate accumulation.Results:A statistically significant correlation was found between k m and VO at stage 6 (r = -0.69, P = .01). In addition, statistically significant correlations were observed between CMJ peak force production and VO2 at stage 2 (r = .66, P = .02), stage 3 (r = .70, P = .01), and stage 4 (r = .58, P = .04). No other statistically significant correlations were observed.Conclusion:These data suggest that greater muscle stiffness and less power are associated with greater RE. Future study in this area should focus on determining the mechanisms behind this relationship and how to best apply them to a running population through training techniques.

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