Effects of Isometric Plantar-Flexion on the Lower Limb Muscle and Lumbar Tissue Stiffness

Abstract

Purpose: This study investigated the effects of isometric plantar-flexion against different resistances on the thoracolumbar fascia (TLF), erector spinae (ES), and gastrocnemius stiffness by shear wave elastography (SWE). The purpose was to explore the interaction between the lower limb muscle and lumbar tissue in the myofascial tensegrity network.Methods: Twenty healthy young female were recruited in this study. The stiffness of the TLF, ES, medial gastrocnemius (MG), and lateral gastrocnemius (LG) was measured by SWE under four isometric plantar-flexion resistance conditions. The resistance conditions involved 0% maximum voluntary isometric contraction (MVIC), 20% MVIC, 40% MVIC, and 60% MVIC.Results: There was a strong correlation between the stiffness change of MG and that of TLF (r = 0.768–0.943, p < 0.001) and ES (r = 0.743–0.930, p < 0.001), while it was moderate to strong correlation between MG and that of LG (r = 0.588–0.800, p < 0.001). There was no significant difference in the stiffness between the nondominant and dominant sides of TLF and ES under the resting position (p > 0.05). The increase in stiffness of the TLF, ES, MG, and LG, with MVIC percentage (p < 0.05), and the stiffness of TLF and ES on the nondominant side is much higher than that on the dominant side.Conclusions: Our data shows that isometric plantar-flexion has a significant effect on the stiffness of the lumbar soft tissue and gastrocnemius. The gastrocnemius has a strong correlation with the stiffness changes of TLF and ES, which provides preliminary evidence for exploring the myofascial tensegrity network between the dorsal side of the lower limb muscle and lumbar tissue.

Is thoracolumbar fascia shear‐wave modulus affected by active and passive knee flexion?

“…The present TLF SWE modulus values at rest were much lower than those reported in a series of studies by Chen et al (2020Chen et al ( , 2021Chen et al ( , 2022) (~40 kPa). This is because we did not multiply the shear-wave velocity by a factor of 3, while Chen et al (2020Chen et al ( , 2021Chen et al ( , 2022 used the values obtained by the device. Further, Chen et al (2020Chen et al ( , 2021Chen et al ( , 2022 quantified stiffness by placing the probe axially relative to the long axis of the body, whereas we acquired images in the longitudinal orientation with the probe along the long axis of the body.…”

“…Very few studies report SWE modulus values of the TLF in healthy individuals (Chen et al, 2020(Chen et al, , 2021(Chen et al, , 2022. The present TLF SWE modulus values at rest were much lower than those reported in a series of studies by Chen et al (2020Chen et al ( , 2021Chen et al ( , 2022) (~40 kPa). This is because we did not multiply the shear-wave velocity by a factor of 3, while Chen et al (2020Chen et al ( , 2021Chen et al ( , 2022 used the values obtained by the device.…”

“…This is because we did not multiply the shear-wave velocity by a factor of 3, while Chen et al (2020Chen et al ( , 2021Chen et al ( , 2022 used the values obtained by the device. Further, Chen et al (2020Chen et al ( , 2021Chen et al ( , 2022 quantified stiffness by placing the probe axially relative to the long axis of the body, whereas we acquired images in the longitudinal orientation with the probe along the long axis of the body. It is known that elastography measures largely depend on the orientation of the probe relative to the fibers of the underlying tissue (Gennisson et al, 2010).…”

“…An in vivo experimental study has also reported that evaluation of TLF SWE modulus shows high reliability and that TLF modulus increases as the trunk flexion angle increases (Chen et al., 2020 ). Moreover, there is evidence that the SWE modulus of the posterior thigh muscles can be influenced by pelvic movement which, in turn, can affect TLF function (Nakamura et al., 2016 ) while isometric plantar flexion influences the stiffness of the paraspinal and gastrocnemius muscles, which implies that there is a connection between fascia and muscles of the “superficial back line” (Chen et al., 2022 ). To the best of our knowledge, the changes in lumbar fascia and posterior thigh fascia stiffness during passive knee stretches using SWE have not been previously examined.…”

Effects of Knee Joint Angle and Contraction Intensity on the Triceps Surae Stiffness

“…A effect size of 3.69 was calculated by the sample size calculator G∗Power 3.1.9.2, alongside a power of 95% and a significance level of 0.05. The experience of our previous study has also been taken into account (n = 20; Chen et al, 2022 ).…”