Shear elastic modulus is a reproducible index reflecting the passive mechanical properties of medial gastrocnemius muscle belly

Abstract

BackgroundPassive mechanical properties are important in muscle function because they are related to the muscle extensibility. Recently, the assessment of muscle shear elastic modulus using shear-wave elastographic (SWE) imaging was developed. However, reliability and validity of shear elastic modulus measurements during passive stretching remain undefined.PurposeTo investigate the reproducibility and validity of the shear elastic modulus measured by SWE imaging during passive stretching.Material and MethodsTen healthy men volunteered for this study. The shear elastic modulus of medial gastrocnemius (MG) muscle belly was measured using ultrasonic SWE imaging during passive dorsiflexion. To assess the intra-session and inter-day reliabilities, the protocol was performed twice by the same investigator with a 5-min rest period between measurement sessions and twice on two different days by the same investigator with a 1–2-week interval between the two sessions. To assess the inter-investigator reliability, the protocol was performed on the same day by two investigators with a 5-min rest between measurement sessions. In addition, B-mode ultrasonography was used to determine the displacement of myotendinous junction (MTJ) of MG during passive ankle dorsiflexion.ResultsThe intra-session, inter-day, and inter-investigator reliabilities of the method was confirmed on the basis of acceptably low coefficient of variations and substantially high intraclass correlation coefficients. In addition, a significant correlation was found between MTJ displacement and shear elastic modulus.ConclusionThese results suggested that shear elastic modulus measured using SWE imaging is a reproducible index reflecting the passive mechanical properties.

Stiffness mapping of lower leg muscles during passive dorsiflexion

“…Because of the within-muscle variability of the shear modulus, it is important that the measurements are performed within muscle region such that results can be compared between participants and studies. For the GM muscle, reliability was similar to that obtained by Nakamura et al (2016) (CV between 5 and 10%) and was slightly better than that reported by Freitas et al (2015) (SEM of 14.8 kPa for GM at 75% of ankle maximum ROM in dorsiflexion). The novelty of the present study is the assessment of the inter-day reliability of the other plantar flexor muscles.…”

“…Previous studies estimated the passive behavior of plantar flexors by measuring the shear modulus of the gastrocnemius medialis (GM) muscle during passive dorsiflexion using shear wave elastography (e.g. Ma€ ısetti et al 2012;Chernak et al 2013;Hug et al 2013;Chino & Takahashi, 2015;Freitas et al 2015;Hirata et al 2015Hirata et al , 2016Taniguchi et al 2015;Nakamura et al 2016). To our knowledge, only two studies completed the investigation on the three heads of the triceps surae [GM, the gastrocnemius lateralis (GL) and the soleus (SOL)] (Hirata et al 2015(Hirata et al , 2016.…”

Age‐related changes in muscle elasticity and thickness of the lower extremities are associated with physical functions among community‐dwelling older women

“…TUG and FSST are known as the major methods for evaluating dynamic balance, and they are well correlated with gait speed . A previous study reported that the elasticity of the MG was related to its flexibility . Menz et al showed that ankle flexibility measured on the modified weight‐bearing lunge test was an independent predictor of dynamic balance ability and gait speed .…”

“…18,27 A previous study reported that the elasticity of the MG was related to its flexibility. 11 Menz et al showed that ankle flexibility measured on the modified weight-bearing lunge test was an independent predictor of dynamic balance ability and gait speed. 12 Furthermore, several studies reported that improvements of hip and ankle flexibility were associated with increased gait speed.…”

“…The muscle thickness of the quadriceps femoris is correlated with knee extension strength, gait speed and Timed Up and Go test (TUG) score . Meanwhile, the muscle elasticity is associated with muscle flexibility, and the ankle plantar flexor flexibility is a predictor of dynamic balance ability and gait speed . Furthermore, several authors reported that improvements of the ankle plantar flexor and hip flexor flexibility led to increased gait speed .…”