The aim of the present study was to assess reliability shear elastic modulus measurements performed using supersonic imaging (SSI) in nine resting muscles (i.e. gastrocnemius medialis, tibialis anterior, vastus lateralis, rectus femoris, triceps brachii, biceps brachioradialis, adductor pollicis obliquus and abductor digiti minimi) different architectures typologies. Thirty healthy subjects were randomly assigned intra-session (n = 20), inter-day 21) inter-observer 16) experiments. Muscle...

This pilot study was designed to determine whether the shear elastic modulus measured using supersonic imaging can be used accurately estimate muscle activity level. Using direct visual feedback of torque, six healthy subjects were asked perform two incremental isometric elbow flexions, consisting linear torque ramps 30 s from 0 40% maximal voluntary contraction. Both electromyographic (EMG) and continuously in biceps brachii during ramps. There significant regression (P<0.001) between EMG...

Background Estimation of an individual muscle force still remains one the main challenges in biomechanics. In this way, present study aimed: (1) to determine whether elastography technique called Supersonic Shear Imaging (SSI) could be used estimate force, (2) compare estimation that provided by surface electromyography (EMG), and (3) effect pennation fibers on accuracy estimation. Methods Results Eleven subjects participated two experimental sessions; was devoted shear elastic modulus...

The aim of this study was to determine the effects 14 wk plyometric training on mechanical properties Achilles tendon. Nineteen subjects were randomly assigned trained or control group. Cross-sectional area (CSA), stiffness, and dissipation coefficient tendon measured before after period. In group, a decrease in (-35.0%; P<0.05) an upward trend stiffness (+24.1%) found, without any changes CSA (P>0.05). Plyometric enhances muscular tension transmission mainly through reduction energy...

Electromechanical delay (EMD) represents the time lag between muscle activation and force production is used to assess function in healthy pathological subjects. There no experimental methodology quantify actual contribution of each series elastic component structures that together contribute EMD. We designed present study determine, using very high frame rate ultrasound (4 kHz), onset fascicles tendon motion induced by electrical stimulation. Nine subjects underwent two bouts composed five...

Changes in muscle stiffness after exercise-induced damage have been classically inferred from passive torque-angle curves. Elastographic techniques can be used to estimate the shear modulus of a localized muscular area. This study aimed quantify changes elastic different regions elbow flexors eccentric exercise and their relation length.Shear transverse relaxation time (T2 ) were measured biceps brachii brachialis muscles sixteen participants, before, 1 h, 48 h 21 days three sets ten maximal...

To compare tendon elastic and structural properties of healthy individuals with those Achilles or patellar tendinopathy. Sixty-seven participants (22 tendinopathy, 17 28 controls) were recruited between March 2015 2016. Shear wave velocity (SWV), an index tissue modulus, thickness measured bilaterally at mid-tendon insertional regions tendons by examiner blinded to group. Analysis covariance, adjusted for age, body mass index, sex was used differences in SWV the two tendinopathy groups...

Assessment of muscle mechanical properties may provide clinically valuable information for follow-up patients with Duchenne muscular dystrophy (DMD) through the course their disease. In this study we aimed to assess effect DMD on stiffness relaxed muscles using elastography (supersonic shear imaging).Fourteen and 13 control subjects were studied. Six measured at 2 lengths (shortened stretched): gastrocnemius medialis (GM); tibialis anterior (TA); vastus lateralis (VL); biceps brachii (BB);...

This study aimed at evaluating the effects of mental and muscle fatigue on table tennis performance. Mental (MF) was induced by completion 90 minutes AX-CPT; an eccentric exercise performed with elbow flexors (biceps fatigue, BF) or knee extensors (quadriceps QF). The control condition consisted watching a movie. Stroke parameters (speed accuracy ball), as well feelings force production capacity (BF, MF conditions) (QF condition), were assessed pre post protocols. Feelings increased Force...

Abstract It is challenging to differentiate the mechanical properties of synergist muscles in vivo . Shear wave elastography can be used quantify shear modulus (i.e. an index stiffness) a specific muscle. This study assessed passive behavior lower leg during dorsiflexion performed with knee fully extended (experiment 1, n = 22) or flexed at 90° 2, 20). The measurements were repeated twice experiment 1 assess inter‐day reliability. During both experiments, following plantar flexors was...

The present study was designed to determine whether fatigue alters the ability estimate an index of individual muscle force from shear elastic modulus measurements (experiment I), and test this technique highlight changes in load sharing within a redundant group during isometric fatiguing task II). Twelve subjects participated experiment I, which consisted smooth linear torque ramps 0 80% maximal voluntary contraction (MVC) performed before after protocol, beginning at 40% MVC stopped when...

The present study aimed to investigate the effects of selective fatigue (i.e., one muscle quadriceps) on load sharing strategies during submaximal knee extensions. Shear wave elastography was used measure shear elastic modulus, as this is considered be an index individual force. Sixteen participants attended two experimental sessions that each involved six 10-s extensions at 20% maximal voluntary contraction (MVC) followed by a sustained isometric extension MVC, until task failure (Tlim)....

The mechanical properties of hamstring muscles are usually inferred from global passive torque/angle relationships, in combination with adjoining tissues crossing the joint investigated. Shear modulus measurement provides an estimate changes muscle-tendon stiffness and tension. This study aimed to assess individual behavior each muscle different stretching positions using shear wave elastography.The was measured during a standardized slow knee extension (PKE, 80% maximal range motion) on...

Eccentric training is a mechanical loading classically used in clinical environment to rehabilitate patients with tendinopathies. In this context, eccentric supposed alter tendon properties but interaction the other components of muscle-tendon complex remains unclear. The aim study was determine specific effects 14 wk on muscle and assessed active passive conditions vivo. Twenty-four subjects were randomly divided into trained group ( n = 11) control 13). Stiffness parts series elastic...