Abstract High strain magnitude and low frequency are important stimuli for tendon adaptation. Increasing the rate duration of applied may enhance adaptive responses. Therefore, our purpose was to investigate effect on Achilles The study included two experimental groups (n=14 n=12) a control group (n=13). participants exercised (14 weeks, 4x/week) according reference protocol, featuring high (~6.5%) (0.17 Hz, 3 s loading/3 relaxation) one leg with either higher (one-legged jumps) or longer...

According to the force–length–velocity relationships, muscle force potential is determined by operating length and velocity, which affects energetic cost of contraction. During running, human soleus produces mechanical work through active shortening provides majority propulsion. The trade-off between production alterations force–length force–velocity potentials (i.e. fraction maximum according curves) might mediate running. By mapping velocity fascicles onto experimentally assessed curves,...

Abstract According to the force-length-velocity relationships, muscle force potential during locomotion is determined by operating fibre length and velocity. We measured fascicle muscle-tendon unit velocity as well activity of human vastus lateralis (VL) walking running. Furthermore, we VL force-length relationship experimentally calculated force-velocity potentials (i.e. fraction maximum according curves) for both gaits. During active state stance phase, fascicles showed significantly (p...

Wolf M, Böhm S, Brand Kreymann G. Proinflammatory cytokines interleukin 1β and tumor necrosis factor α inhibit growth hormone stimulation of insulin-like I synthesis receptor mRNA levels in cultured rat liver cells. Eur J Endocrinol 1996;135:729–37. ISSN 0804–4643 Low (IGF-I) critical illness are observed despite increased or normal (GH). The mechanisms for this apparent GH resistance have not been elucidated. As many the acute inflammatory responses mediated by proinflammatory (IL-1β)...

The human body is an outstandingly complex machine including around 1000 muscles and joints acting synergistically. Yet, the coordination of enormous amount degrees freedom needed for movement mastered by our one brain spinal cord. idea that some synergistic neural components exist was already suggested at beginning 20th century. Since then, it has been widely accepted central nervous system might simplify production avoiding control each muscle individually. Instead, be controlling in...

The purpose of the current study was to assess in vivo Achilles tendon (AT) mechanical loading and strain energy during locomotion. We measured AT length considering its curve-path shape. Eleven participants walked at 1.4 m/s ran 2.5 3.5 on a treadmill. defined as distance between origin gastrocnemius medialis myotendinous junction (MTJ) calcaneal insertion. MTJ tracked using ultrasonography projected reconstructed skin surface account for misalignment. Skin-to-bone displacements were...

Muscle synergies as functional low-dimensional building blocks of the neuromotor system regulate activation patterns muscle groups in a modular structure during locomotion. The purpose current study was to explore how older adults organize locomotor counteract unpredictable and predictable gait perturbations perturbed steps recovery steps. Sixty-three healthy (71.2±5.2 years) participated study. Mediolateral anteroposterior walking were introduced using treadmill. extracted from...

Although symmetry of A chilles tendon ( AT ) properties between legs is commonly assumed in research and clinical settings, different loading profiles both daily life (i.e., foot dominance) may affect the a side‐depended manner. Therefore, were examined with regard to legs. Thirty‐six male healthy adults (28 ± 4 years), who physically active but not involved sports featuring dissimilar leg load participated. Mechanical morphological non‐dominant dominant measured by means ultrasound,...

There is evidence that a non‐uniform adaptation of muscle and tendon in young athletes results increased stress during mid‐adolescence. The present longitudinal study investigated the development morphological mechanical properties volleyball time period 2 years from mid‐adolescence to late adolescence. Eighteen elite participated magnetic resonance imaging ultrasound‐dynamometry sessions determine quadriceps femoris strength, vastus lateralis, medialis intermedius morphology, patellar (16 ±...

The purpose of this study was to assess the effectiveness a specific exercise intervention mechanisms control dynamic postural stability under unstable conditions in old adults. Forty‐seven adults (65‐80 years) were assigned 2 experimental groups (muscle strength group, n = 15; perturbation‐based 16) and group (n 16). performed resistance exercises for leg trunk muscles, while exercised conditions. training duration 14 weeks, with sessions twice week 1.5 hours. Muscle strength, balance...

Humans achieve greater jump height during a counter-movement (CMJ) than in squat (SJ). However, the crucial difference is mean mechanical power output propulsion phase, which could be determined by intrinsic neuro-muscular mechanisms for production. We measured M. vastus lateralis (VL) fascicle length changes and activation patterns assessed force–length, force–velocity power–velocity potentials jumps. Compared with SJ, VL fascicles operated on more favourable portion of force–length curve...

With the double stimulus of mechanical loading and maturation acting on muscle-tendon unit, adolescent athletes might be at increased risk developing imbalances muscle strength tendon properties. This longitudinal study aims to provide detailed information how athletic training affects time course adaptation during adolescence. In 12 elite (A) 8 similar-aged controls (C), knee extensor patellar properties were measured over 1 yr in 3-mo intervals. A linear mixed-effects model was used...

The interaction of muscle and tendon is major importance for movement performance a balanced development strength stiffness could protect athletes from overuse injury. However, do not necessarily adapt in uniform manner during training process. diagnostic routine to assess both the capacity mechanical properties tendons would enable detection muscle-tendon imbalances, indicate if should target or allow precise prescription loads optimize adaptation. This perspective article discusses...

Imbalances between muscle strength and tendon stiffness influence the mechanical demand on (i.e., strain) may increase injury risk. The purpose of this study was to identify muscle-tendon imbalances promote a more balanced musculotendinous adaptation through personalized assessment exercise prescription concept in female adolescent handball athletes (13-16 years). At four measurement time points during competitive season, we used dynamometry ultrasonography assess knee extensor strength,...

Our objective was to explore how the potential for energy transfer between ankle and knee joint via biarticular gastrocnemii muscles is modulated during unpredictable adapted trip-like drop-like gait perturbations. Using kinematic parameters of joints, two joints determined as fraction contact time when angles are in-phase. Additionally, electromyographic activity gastrocnemius medialis lateralis were captured The increased 1.6-fold in 2.5-fold perturbations compared unperturbed walking,...

Introduction Diversity of activation patterns within synergistic muscles can be important for stability control in challenging conditions. This study investigates the similarity triceps surae and quadriceps femoris effects unstable surface during a visually guided postural task. Methods Eighteen healthy adults performed anteroposterior tracking task on both stable surfaces. Electromyographic activity (gastrocnemius medialis, gastrocnemius lateralis, soleus) (vastus vastus rectus femoris) was...