Age-related differences in Achilles tendon properties and triceps surae muscle architecture in vivo

2012 ◽  
Vol 113 (10) ◽  
pp. 1537-1544 ◽  
Author(s):  
Lauri Stenroth ◽  
Jussi Peltonen ◽  
Neil J. Cronin ◽  
Sarianna Sipilä ◽  
Taija Finni
Keyword(s):  
Achilles Tendon ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Cross Sectional Area ◽  
Triceps Surae ◽  
Sectional Area ◽  
Cross Sectional ◽  
Tendon Stiffness ◽  
Triceps Surae Muscle ◽  
Age Related

This study examined the concurrent age-related differences in muscle and tendon structure and properties. Achilles tendon morphology and mechanical properties and triceps surae muscle architecture were measured from 100 subjects [33 young (24 ± 2 yr) and 67 old (75 ± 3 yr)]. Motion analysis-assisted ultrasonography was used to determine tendon stiffness, Young's modulus, and hysteresis during isometric ramp contractions. Ultrasonography was used to measure muscle architectural features and size and tendon cross-sectional area. Older participants had 17% lower ( P < 0.01) Achilles tendon stiffness and 32% lower ( P < 0.001) Young's modulus than young participants. Tendon cross-sectional area was also 16% larger ( P < 0.001) in older participants. Triceps surae muscle size was smaller ( P < 0.05) and gastrocnemius medialis muscle fascicle length shorter ( P < 0.05) in old compared with young. Maximal plantarflexion force was associated with tendon stiffness and Young's modulus ( r = 0.580, P < 0.001 and r = 0.561, P < 0.001, respectively). Comparison between old and young subjects with similar strengths did not reveal a difference in tendon stiffness. The results suggest that regardless of age, Achilles tendon mechanical properties adapt to match the level of muscle performance. Old people may compensate for lower tendon material properties by increasing tendon cross-sectional area. Lower tendon stiffness in older subjects might be beneficial for movement economy in low-intensity locomotion and thus optimized for their daily activities.

scholarly journals Triceps surae muscle-tendon properties in older endurance- and sprint-trained athletes

2016 ◽  
Vol 120 (1) ◽  
pp. 63-69 ◽  
Author(s):  
Lauri Stenroth ◽  
Neil J. Cronin ◽  
Jussi Peltonen ◽  
Marko T. Korhonen ◽  
Sarianna Sipilä ◽  
...  
Keyword(s):  
Achilles Tendon ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Muscle Architecture ◽  
Triceps Surae ◽  
Training Experience ◽  
Tendon Stiffness ◽  
Triceps Surae Muscle ◽  
Age Related ◽  
Tendon Properties

Previous studies have shown that aging is associated with alterations in muscle architecture and tendon properties (Morse CI, Thom JM, Birch KM, Narici MV. Acta Physiol Scand 183: 291–298, 2005; Narici MV, Maganaris CN, Reeves ND, Capodaglio P. J Appl Physiol 95: 2229–2234, 2003; Stenroth L, Peltonen J, Cronin NJ, Sipila S, Finni T. J Appl Physiol 113: 1537–1544, 2012). However, the possible influence of different types of regular exercise loading on muscle architecture and tendon properties in older adults is poorly understood. To address this, triceps surae muscle-tendon properties were examined in older male endurance (OE, n = 10, age = 74.0 ± 2.8 yr) and sprint runners (OS, n = 10, age = 74.4 ± 2.8 yr), with an average of 42 yr of regular training experience, and compared with age-matched [older control (OC), n = 33, age = 74.8 ± 3.6 yr] and young untrained controls (YC, n = 18, age = 23.7 ± 2.0 yr). Compared with YC, Achilles tendon cross-sectional area (CSA) was 22% ( P = 0.022), 45% ( P = 0.001), and 71% ( P < 0.001) larger in OC, OE, and OS, respectively. Among older groups, OS had significantly larger tendon CSA compared with OC ( P = 0.033). No significant between-group differences were observed in Achilles tendon stiffness. In older groups, Young's modulus was 31-44%, and maximal tendon stress 44–55% lower, than in YC ( P ≤ 0.001). OE showed shorter soleus fascicle length than both OC ( P < 0.05) and YC ( P < 0.05). These data suggest that long-term running does not counteract the previously reported age-related increase in tendon CSA, but, instead, may have an additive effect. The greatest Achilles tendon CSA was observed in OS followed by OE and OC, suggesting that adaptation to running exercise is loading intensity dependent. Achilles tendon stiffness was maintained in older groups, even though all older groups displayed larger tendon CSA and lower tendon Young's modulus. Shorter soleus muscle fascicles in OE runners may be an adaptation to life-long endurance running.

Effects of cross-sessional area and aspect ratio coupled with orientation on mechanical properties and deformation behavior of Cu nanowires

2021 ◽  
Author(s):  
Hui Cao ◽  
Wenke Chen ◽  
Zhiyuan Rui ◽  
Changfeng Yan
Keyword(s):  
Mechanical Properties ◽  
Aspect Ratio ◽  
Yield Stress ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Cu Nanowires ◽  
The Cross

Abstract Metal nanomaterials exhibit excellent mechanical properties compared with corresponding bulk materials and have potential applications in various areas. Despite a number of studies of the size effect on Cu nanowires mechanical properties with square cross-sectional, investigations of them in rectangular cross-sectional with various sizes at constant volume are rare, and lack of multifactor coupling effect on mechanical properties and quantitative investigation. In this work, the dependence of mechanical properties and deformation mechanisms of Cu nanowires/nanoplates under tension on cross-sessional area, aspect ratio of cross-sectional coupled with orientation were investigated using molecular dynamics simulations and the semi-empirical expressions related to mechanical properties were proposed. The simulation results show that the Young’s modulus and the yield stress sharply increase with the aspect ratio except for the <110>{110}{001} Cu nanowires/nanoplates at the same cross-sectional area. And the Young’s modulus increases while the yield stress decreases with the cross-sectional area of Cu nanowires. However, both of them increase with the cross-sectional area of Cu nanoplates. Besides, the Young’s modulus increases with the cross-sectional area at all the orientations. The yield stress shows a mildly downward trend except for the <111> Cu nanowires with increased cross-sectional area. For the Cu nanowires with a small cross-sectional area, the surface force increases with the aspect ratio. In contrast, it decreases with the aspect ratio increase at a large cross-sectional area. At the cross-sectional area of 13.068 nm2, the surface force decreases with the aspect ratio of the <110> Cu nanowires while it increases at other orientations. The surface force is a linearly decreasing function of the cross-sectional area at different orientations. Quantitative studies show that Young’s modulus and yield stress to the aspect ratio of the Cu nanowires satisfy exponent relationship. In addition, the main deformation mechanism of Cu nanowires is the nucleation and propagation of partial dislocations while it is the twinning-dominated reorientation for Cu nanoplates.

Tendinopathy alters mechanical and material properties of the Achilles tendon

2010 ◽  
Vol 108 (3) ◽  
pp. 670-675 ◽  
Author(s):  
Shruti Arya ◽  
Kornelia Kulig
Keyword(s):  
Achilles Tendon ◽  
Young’S Modulus ◽  
Material Properties ◽  
Young's Modulus ◽  
Treatment Strategies ◽  
Achilles Tendinopathy ◽  
Cross Sectional ◽  
Tendon Stiffness ◽  
And Gender

The purpose of this study was to investigate the in vivo material and mechanical properties of the human Achilles tendon in the presence of tendinopathy. Real-time ultrasound imaging and dynamometry were used to assess Achilles tendon stiffness, Young's modulus, stress, strain, and cross-sectional area (CSA) in 12 individuals with Achilles tendinopathy and 12 age- and gender-matched controls. The results of this study suggest that tendinopathy weakens the mechanical and material properties of the tendon. Tendinopathic tendons had greater CSA, lower tendon stiffness, and lower Young's modulus. These alterations in mechanical characteristics may put the Achilles tendon at a higher risk to sustain further injury and prolong the time to recovery. Results from this study may be used to design treatment strategies that specifically target these deficits, leading to faster and permanent recovery from tendinopathy.

scholarly journals MRI-based quantification of ophthalmic changes in healthy volunteers during acute 15° head-down tilt as an analogue to microgravity

2021 ◽  
Vol 18 (177) ◽  
Author(s):  
Stuart H. Sater ◽  
Austin M. Sass ◽  
Akari Seiner ◽  
Gabryel Conley Natividad ◽  
Dev Shrestha ◽  
...  
Keyword(s):  
Optic Nerve ◽  
Young’S Modulus ◽  
Structural Changes ◽  
Young's Modulus ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Fluid Shifts ◽  
Magnetic Resonance Imaging Mri ◽  
Ophthalmic Changes

Spaceflight is known to cause ophthalmic changes in a condition known as spaceflight-associated neuro-ocular syndrome (SANS). It is hypothesized that SANS is caused by cephalad fluid shifts and potentially mild elevation of intracranial pressure (ICP) in microgravity. Head-down tilt (HDT) studies are a ground-based spaceflight analogue to create cephalad fluid shifts. Here, we developed non-invasive magnetic resonance imaging (MRI)-based techniques to quantify ophthalmic structural changes under acute 15° HDT. We specifically quantified: (i) change in optic nerve sheath (ONS) and optic nerve (ON) cross-sectional area, (ii) change in ON deviation, an indicator of ON tortuosity, (iii) change in vitreous chamber depth, and (iv) an estimated ONS Young's modulus. Under acute HDT, ONS cross-sectional area increased by 4.04 mm 2 (95% CI 2.88–5.21 mm 2 , p < 0. 000), while ON cross-sectional area remained nearly unchanged (95% CI −0.12 to 0.43 mm 2 , p = 0.271). ON deviation increased under HDT by 0.20 mm (95% CI 0.08–0.33 mm, p = 0.002). Vitreous chamber depth decreased under HDT by −0.11 mm (95% CI −0.21 to −0.03 mm, p = 0.009). ONS Young's modulus was estimated to be 85.0 kPa. We observed a significant effect of sex and BMI on ONS parameters, of interest since they are known risk factors for idiopathic intracranial hypertension. The tools developed herein will be useful for future analyses of ON changes in various conditions.

Harder than Diamond: Determining the Cross-Sectional Area and Young's Modulus of Molecular Rods

2005 ◽  
Vol 117 (45) ◽  
pp. 7598-7601 ◽  
Author(s):  
Lior Itzhaki ◽  
Eli Altus ◽  
Harold Basch ◽  
Shmaryahu Hoz
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
The Cross
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