Effect of a 5‐week static stretching program on hardness of the gastrocnemius muscle

Akagi, Ryota; Takahashi, Hideyuki

doi:10.1111/sms.12111

Cited by 105 publications

(110 citation statements)

References 35 publications

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“…There are several possible explanations for this discrepancy; anisotropic properties in the human skeletal muscle may be a cause in addition to the differences in modulus and devices used for the measurements. 18,[22][23][24] With the use of the MRE, the shear moduli measured in the direction parallel to the muscle fibre were greater than those measured in the direction perpendicular to the fibre, whereas the values themselves were very different from those reported in earlier studies. 25 In the present study, therefore, we did not express the masseter muscle elasticity in kilopascal using the Young's moduli because the aim of present study was to verify the correlation between the EI ratios and the elasticity of the muscle phantoms.…”

Section: Discussioncontrasting

confidence: 50%

Evaluation of the masseter muscle elasticity with the use of acoustic coupling agents as references in strain sonoelastography

Nakayama

Ariji²,

Nishiyama³

et al. 2015

Dentomaxillofacial Radiology

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Objectives: To verify the use of a single coupling agent as a reference to obtain the elasticity index (EI) ratios and to investigate the EI ratios of the masseter muscles of healthy volunteers. Methods: Muscle phantoms with known elasticity (20, 40 and 60 kPa in the Young's modulus) were examined by strain-type sonoelastography using a coupling agent as the reference. Eight examiners tested soft (with 7 kPa) and hard (with 40 kpa) reference coupling agents separately. The correlation coefficients were determined between the EI ratio and Young's modulus of muscle phantoms. The interclass correlation coefficients were calculated for inter-and intraexaminer agreement. Results: Strong correlations were found between the EI ratios and Young's modulus for both soft and hard references. The variations of the EI ratios were larger with soft coupling agents than those with hard coupling agents, and they increased in phantoms with 60 kPa elasticity. There were no differences in the EI ratios of the masseter muscle at rest between males and females or between the right and left sides. The ratio increased during clenching. Conclusions: The hard reference coupling agent was suitable for obtaining EI ratio of the masseter muscle. No differences were found in the EI ratios of the masseter muscle either between sexes or between the right and left sides at rest, and the ratios increased with the widening of their variations during clenching.

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Section: Discussioncontrasting

confidence: 50%

Evaluation of the masseter muscle elasticity with the use of acoustic coupling agents as references in strain sonoelastography

Nakayama

Ariji²,

Nishiyama³

et al. 2015

Dentomaxillofacial Radiology

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“…A few studies have explored the ability of SWE to evaluate the physiological responses of resting muscles (i.e., muscles that are not contracting or stretching during measurement) to short-term active or passive muscular solicitation [21,22] using eccentric injury models and plantar flexor [23,24] or elbow flexor eccentric contraction models [25]. Green et al [23] explored the effects of downward running on a treadmill on the plantar flexor muscles under experimental conditions using magnetic resonance elastography (MRE).…”

Section: Introductionmentioning

confidence: 99%

Shear-Wave Elastography Assessments of Quadriceps Stiffness Changes prior to, during and after Prolonged Exercise: A Longitudinal Study during an Extreme Mountain Ultra-Marathon

et al. 2016

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In sports medicine, there is increasing interest in quantifying the elastic properties of skeletal muscle, especially during extreme muscular stimulation, to improve our understanding of the impact of alterations in skeletal muscle stiffness on resulting pain or injuries, as well as the mechanisms underlying the relationships between these parameters. Our main objective was to determine whether real-time shear-wave elastography (SWE) can monitor changes in quadriceps muscle elasticity during an extreme mountain ultra-marathon, a powerful mechanical stress model. Our study involved 50 volunteers participating in an extreme mountain marathon (distance: 330 km, elevation: +24,000 m). Quantitative SWE velocity and shear modulus measurements were performed in most superficial quadriceps muscle heads at the following 4 time points: before the race, halfway through the race, upon finishing the race and after recovery (+48 h). Blood biomarker levels were also measured. A significant decrease in the quadriceps shear modulus was observed upon finishing the race (3.31±0.61 kPa) (p<0.001) compared to baseline (3.56±0.63 kPa), followed by a partial recovery +48 h after the race (3.45±0.6 kPa) (p = 0.002) across all muscle heads, as well as for each of the following three muscle heads: the rectus femoris (p = 0.003), the vastus medialis (p = 0.033) and the vastus lateralis (p = 0.001). Our study is the first to assess changes in muscle stiffness during prolonged extreme physical endurance exercises based on shear modulus measurements using non-invasive SWE. We concluded that decreases in stiffness, which may have resulted from quadriceps overuse in the setting of supra-physiological stress caused by the extreme distance and unique elevation of the race, may have been responsible for the development of inflammation and muscle swelling. SWE may hence represent a promising tool for monitoring physiologic or pathological variations in muscle stiffness and may be useful for diagnosing and monitoring muscle changes.

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“…Increases in muscle modulus due to exercise have been seen previously (Kovanen et al 1984). Conversely, muscle modulus has been shown to decrease after stretching interventions (Akagi and Takahashi 2014). Our study used both increased eccentric loading and passive stretching as part of the intervention protocol.…”

Section: Effects Of Nordic Hamstring Strength Training On Muscle Archmentioning

confidence: 82%

The effect of Nordic hamstring strength training on muscle architecture, stiffness, and strength

et al. 2017

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This is an author-produced, peer-reviewed version of this article. The final, definitive version of this document can be found online at Hamstring strain injury is a frequent and serious injury in competitive and recreational sports. While Nordic hamstring (NH) eccentric strength training is an effective hamstring injury prevention method, the protective mechanism of this exercise is not understood. Strength training increases muscle strength, but also alters muscle architecture and stiffness; all three factors may be associated with reducing muscle injuries. The purpose of this study was to examine the effects of NH eccentric strength training on hamstring muscle architecture, stiffness, and strength.Methods: Twenty healthy participants were randomly assigned to an eccentric training group or control group. Control participants performed static stretching, while experimental participants performed static stretching and NH training for 6 weeks. Pre-and post-intervention measurements included: hamstring muscle architecture and stiffness using ultrasound imaging and elastography, and maximal hamstring strength measured on a dynamometer. Results:The experimental group, but not the control group, increased volume (131.5 vs. 145.2 cm 3 , p<0.001) and physiological cross-sectional area (16.1 vs. 18.1 cm 2 , p=0.032). There were no significant changes to muscle fascicle length, stiffness, or eccentric hamstring strength. Conclusions:The NH intervention was an effective training method for muscle hypertrophy, but, contrary to common literature findings for other modes of eccentric training, did not increase fascicle length. The data suggest the mechanism behind NH eccentric strength training mitigating hamstring injury risk could be increasing volume rather than increasing muscle length. Future research is therefore warranted to determine if muscle hypertrophy induced by NH training lowers future hamstring strain injury risk.

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Effect of a 5‐week static stretching program on hardness of the gastrocnemius muscle

Cited by 105 publications

References 35 publications

Evaluation of the masseter muscle elasticity with the use of acoustic coupling agents as references in strain sonoelastography

Evaluation of the masseter muscle elasticity with the use of acoustic coupling agents as references in strain sonoelastography

Shear-Wave Elastography Assessments of Quadriceps Stiffness Changes prior to, during and after Prolonged Exercise: A Longitudinal Study during an Extreme Mountain Ultra-Marathon

The effect of Nordic hamstring strength training on muscle architecture, stiffness, and strength

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