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...

Previous studies have reported no changes on muscle architecture (MA) after static stretching interventions; however, authors argued that duration and intensity may not been sufficient. A high-intensity intervention targeting the knee flexors with an 8-week was conducted to observe effects biceps femoris long head (BF) architecture. Participants (n = 5) performed average of 3.1 assisted-stretching sessions per week, whereas a control group did perform stretching. The extension passive...

Summary Information regarding the effects of stretching intensity on joint torque–angle response is scarce. The present study examined three static protocols with different intensities and durations passive knee extension seventeen male participants (age ± SD : 23·9 3·6 years, height: 177·0 7·2 cm, BMI 22·47 1·95 kg·m 2 ). was determined according to maximal tolerable torque first repetition: fifty per cent (P50), seventy‐five (P75) maximum without pain (P100). Five repetitions were...

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...

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.

To assess the repeatability of, and measurement agreement between, four sonographic techniques used to quantify biceps femoris long head (BFlh) architecture: (i) static-image with linear extrapolation; extended field-of-view (EFOV) ultrasound probe path (linear-EFOV), using either (ii) straight or (iii) segmented analyses; (iv) EFOV nonlinear analysis (nonlinear-EFOV) follow complex fascicle trajectories.Twenty individuals (24.4 ± 5.7 yr; 175 0.8 cm; 73 9.0 kg) without history of hamstrings...

Abstract To identify biomarkers that precede the decline of human function and independence during lifespan, two important concepts have been introduced in recent decades: sarcopenia dynapenia. While former is originally focused on skeletal muscle loss, latter maximal strength loss. Although dynapenia concept implies inclusion power, practical terms, this has not specifically addressed. For instance, only 2 out 220 studies published between 2008 2023 directly measured power to classify...

Martínez-Serrano, A, Radaelli, R, Trindade de Freitas, T, Alcaraz, PE, and SR. Hamstring muscle stiffness during isometric contractions until task failure in footballers with without injury history. J Strength Cond Res XX(X): 000-000, 2024-Despite various proposed prevention strategies, the incidence of hamstring injuries modern soccer is still elevated. Recent research has focused on exploring how tissue behaves under fatigue conditions as a potential risk factor. This study aimed to...

Abstract Structural muscle properties are critical in health and athletic settings, with magnetic resonance imaging considered the gold standard assessment procedure under static conditions due to its reliability objectivity. Practical limitations, including cost accessibility, have led increasing use of ultrasound as an alternative for skeletal morphological parameters. However, measurements sensitive evaluation assessor experience, which has not been sufficiently explored, yet. Therefore,...

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...

Two experiments (n = 10) were conducted to determine the effects of roller massager (RM) on ankle plantar flexor muscle recovery after exercise-induced damage (EIMD). Experiment 1 examined both functional [i.e., flexion maximal isometric contraction and submaximal (30%) sustained force; dorsiflexion range motion resistance stretch; medial gastrocnemius pain pressure threshold] morphological [cross-sectional area, thickness, fascicle length, angle] variables, before immediately, 1, 24, 48, 72...

Objectives Biceps femoris long‐head architectural assessment using ultrasonography (US) has not been previously described in detail for both acquisition (image capture) and digitization measurement) processes, the effect of US window width is unknown. This study aimed to describe reliability test‐retest minimum detectable difference US‐based biceps measurements. Methods Muscle length was determined by marking muscle‐tendon junction distances. Sonograms were acquired with a 6‐cm image cropped...

This study examined whether a high-intensity, moderate-duration bout of stretching would produce the same acute effects as low-intensity, long-duration stretching. 17 volunteers performed 2 knee-flexor protocols: high-intensity stretch (i. e., 100% maximum tolerable passive torque) with moderate duration (243.5±69.5-s); and low-intensity (50% long (900-s). Passive torque at given sub-maximal angle, peak torque, maximal range motion (ROM), muscle activity were assessed before after each...