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...

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...

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 investigated the effects of active and/or passive warm-up tasks on hamstring muscles stiffness through elastography and torque measurements. On separate occasions, fourteen males randomly completed four protocols comprising Control, Cycling, Foam rolling, or Cycling plus rolling (Mixed). The was assessed shear wave elastography, along with torque-angle relationship maximal range motion (ROM) before, 5, 30 minutes after each experimental condition. At 5 minutes, Mixed decreased...

Redundancy of the neuromuscular system theoretically allows for a redistribution neural drive across muscles (i.e., between-muscle compensation) during fatiguing contraction. Our results suggest that high level common input between (e.g., vastus lateralis and medialis) represents constraint making it less likely to redistribute these muscles. In this way, was only observed share little synaptic gastrocnemius medialis).

Using ultrasound shear wave elastography, the aims of this study were: (a) to evaluate effect massage on stiffness medial gastrocnemius ( MG ) muscle and (b) determine whether (if any) persists over a short period rest. A 7‐min protocol was performed unilaterally in 18 healthy volunteers. Measurements elastic modulus (stiffness) were bilaterally (control massaged leg) moderately stretched position at three time points: before (baseline), directly after (follow‐up 1), following 3 min rest 2)....

Defining the origins of muscle injury has important rehabilitation and exercise applications. However, current knowledge damage mechanics in human remains unclear vivo. This study aimed to determine relationships between muscle-tendon unit during maximal eccentric contractions extent subsequent functional impairments induced by damage.The length unit, fascicles tendinous tissues was continuously measured on gastrocnemius medialis using ultrasonography, time with torque, 10 sets 30 plantar...

Background Electromechanical delay is the time lag between onsets of muscle activation and force production reflects both electro-chemical processes mechanical processes. The aims present study were two-fold: to experimentally determine slack length each head biceps brachii using elastography influence on electromechanical its electro-chemical/mechanical very high frame rate ultrasound. Methods/Results First, 12 participants performed two passive stretches evaluate change in tension for...

Ankle joint range of motion ( ROM ) is notably influenced by the position hip joint. However, this result remains unexplained. Thus, aim study was to test if ankle passive torque and gastrocnemius muscle tension are affected head positions. The shear elastic modulus (measured elastography estimate tension) were collected in nine participants during dorsiflexions performed four conditions (by combining flexion at 90 or 150°, flexed neutral). maximum dorsiflexion angle significantly decreased...

Little is known about the factors that influence coordination of synergist muscles act across same joint, even during single-joint isometric tasks. The overall aim this study was to determine nature relationship between distribution activation and force-generating capacity among three heads triceps surae (soleus [SOL], gastrocnemius medialis [GM] lateralis [GL]). Twenty volunteers performed plantarflexions which GM, GL SOL estimated using electromyography (EMG). Functional muscle...

Although it is known that the muscle activation patterns used to produce even simple movements can vary between individuals, these differences have not been considered prove existence of individual strategies (or signatures). We a machine learning approach (support vector machine) test hypothesis each has unique signatures. Eighty participants performed series pedaling and gait tasks, 53 second experimental session on subsequent day. Myoelectrical activity was measured from eight muscles:...

This study demonstrates that the mechanical properties of plantar flexor muscles and sciatic nerve can adapt mechanically to long-term stretching programs. Although interventions targeting muscular or nonmuscular structures are both effective at increasing maximal range motion, changes in tissue (stiffness) specific structure being preferentially stretched by each program. We provide first vivo evidence stiffness peripheral nerves adapts loading stimuli using appropriate nerve-directed stretching.

ABSTRACT Purpose The application of horizontal resistance is key in sprint training to modulate velocity and promote adaptations. However, the interaction between on muscle excitation remains insufficiently studied. This study assessed electromyographic (EMG) activity thigh gluteal muscles response varying during sprinting. Methods Thirty-seven elite athletes (27 females 10 males) performed two trials under three conditions: a 40-meter maximal without resisted sprints applied by robotic...

Eccentric exercise training is believed to induce an increase in muscle fascicle length. However, the mechanisms underlying this adaptation are not fully understood. This study aimed determine if gastrocnemius medialis length following 8-week eccentric linked changes tissue and joint mechanical properties. Thirty-three physically active young adults were assigned one of two protocols targeting plantar flexors: at 1) long-muscle or 2) short-muscle Fascicle shear modulus assessed using...

Abstract Purpose This study evaluated the effects of eccentric resistance training on hamstring muscles properties in women using oral contraceptives (OC) and naturally menstruating women. Methods Before after intervention, we measured maximal isometric moment knee flexor muscles, thickness shear wave velocity (SWV) biceps femoris long head (BFlh), semitendinosus (ST) semimembranosus (SM) BFlh fascicle length ultrasonography dynamometry. Results The 12-week intervention resulted a modest but...

Abstract It is a long held belief that maximal joint range of motion (ROM) restricted by muscle tension. However, it exists indirect evidence suggesting this assumption may not hold true for some configurations where non-muscular structures, such as the peripheral nerves, are stretched. Direct evidences lacking. This study aimed to determine whether static stretching aiming load sciatic nerve without stretch within plantar flexors effective to: (i) alter stiffness; and (ii) increase ankle’s...

Although cold application (ie, cryotherapy) may be useful to treat sports injuries and prevent muscle damage, it is unclear whether has adverse effects on mechanical properties. This study aimed determine the effect of air‐pulsed cryotherapy stiffness estimated using ultrasound shear wave elastography. Myoelectrical activity, ankle passive torque, modulus (an index stiffness), temperature gastrocnemius medialis were measured before, during an (−30°C) treatment four sets 4 minutes with...

The effect of training on hamstring flexibility has been widely assessed through the measurement maximal range motion or passive torque. However, these global measures do not provide direct information muscle mechanical properties individual muscle. This characterization is crucial to better understand interventions as selective adaptations may occur among synergist muscles. Taking advantage shear wave elastography, we aimed determine whether elite sport athletes exhibit different modulus...

There is growing evidence that each individual has unique movement patterns, or signatures. The exact origin of these signatures, however, remains unknown. We developed an approach can identify muscle activation signatures during two locomotor tasks (walking and pedalling). A linear support vector machine was used to classify 78 participants based on their electromyographic (EMG) patterns measured eight lower limb muscles. To provide insight into decision-making by the learning...