Search results for "eccentric"
showing 10 items of 182 documents
The effects of the Nordic hamstring exercise on sprint performance and eccentric knee flexor strength: A systematic review and meta-analysis of inter…
2021
Objectives: The primary aim of this study was to investigate the effects of the Nordic hamstring exercise (NHE) on sprint performance (i.e., 5, 10 and 20 m) and explore associations between study characteristics and sprint outcomes in team sport players. Secondary aims were to (1) investigate the effects of the NHE on eccentric strength of the knee flexors (ESKF) with categorical subgroup analysis to determine differences between recreationally, well-trained individuals and young athletes, (2) determine the relation between ESKF and sprint performance in team sport players, and (3) explore the effect of study characteristics (i.e., weekly volume, time duration and body mass) on ESKF.Methods…
Modulation of spinal excitability by a sub-threshold stimulation of M1 area during muscle lengthening
2013
Abstract It is well known that the H-reflex amplitude decreases during passive muscle lengthening in comparison with passive shortening. However, this decrease in spinal synaptic efficacy observed during passive lengthening seems to be lesser during eccentric voluntary contraction. The aim of the present study was to examine whether spinal excitability during lengthening condition could be modulated by magnetic brain stimulation. H reflexes of the triceps surae muscles were elicited on 10 young healthy subjects, and conditioned by a sub-threshold transcranial magnetic stimulation (TMS). The conditioning stimulation was applied over the M1 area of triceps surae muscles at an intensity below …
Blood-Borne Markers of Fatigue in Competitive Athletes – Results from Simulated Training Camps
2016
Assessing current fatigue of athletes to fine-tune training prescriptions is a critical task in competitive sports. Blood-borne surrogate markers are widely used despite the scarcity of validation trials with representative subjects and interventions. Moreover, differences between training modes and disciplines (e.g. due to differences in eccentric force production or calorie turnover) have rarely been studied within a consistent design. Therefore, we investigated blood-borne fatigue markers during and after discipline-specific simulated training camps. A comprehensive panel of blood-born indicators was measured in 73 competitive athletes (28 cyclists, 22 team sports, 23 strength) at 3 time…
Effects of electromyostimulation versus voluntary isometric training on elbow flexor muscle strength.
2007
The purpose of this study was to determine whether 7 weeks of standardized (same number and duration of repetitions, sets and rest strictly identical) electromyostimulation training of the elbow flexor muscles would induce strength gains equivalent to those of voluntary isometric training in isometric, eccentric and concentric contractions. Twenty-five males were randomly assigned to an electromyostimulated group (EMS, n=9), a voluntary isometric group (VOL, n=8), or a control group (CON, n=8). Maximal voluntary isometric, eccentric and concentric strength, electromyographic (EMG) activity of the biceps and triceps brachii muscles, elbow flexor muscle activation (twitch interpolation techni…
Acute elevations in serum hormones are attenuated after chronic training with traditional isoinertial but not accentuated eccentric loads in strength…
2017
It has been proposed that the maintenance of acute hormonal responses reveal an efficacy of a training stimulus to evoke ongoing increases in strength and muscle mass. We previously observed that maximum strength continued to improve throughout a 10‐week period in an accentuated eccentric loading group (AEL) but not a traditional isoinertial loading (ISO) group. Therefore, this study investigated whether the magnitude of acute hormonal responses was greater (i.e., maintained) in AEL compared to ISO at the end of the training period. Subjects in AEL (eccentric load = concentric load + 40%) and ISO performed experimental loading tests (three sets of 10 repetitions in the leg press and knee ex…
Comparison of Electromyographic Activity During Hip Extension Exercises Under Gravitational or Inertial Loading Conditions.
2021
Background: Hamstring injury prevention programs include strengthening, especially eccentric exercises using both gravitational and inertial loading. Inertial exercises are characterized by eccentric contractions of high intensity and velocity. This study aimed to analyze the muscular activation of the biceps femoris (BF), semitendinosus (ST), gluteus maximus (GM), and gracilis (GC) muscles during hip extension (HE) exercises performed under both gravitational and inertial loading conditions. Hypothesis: Inertial training would generate a greater activation of HE muscles than gravitational training. Study Design: Cross-sectional study. Level of Evidence: Level 4. Methods: Fifteen resistance…
Adaptive changes in motor control of rhythmic movement after maximal eccentric actions.
2007
Effects of an exhaustive eccentric exercise (EE) on the motor control of maximal velocity rhythmic elbow extension/flexion movement (RM) were examined in eight male students. The exhaustive EE consisted of 100 maximal eccentric actions of the elbow flexor muscles. Movement range was 40-170 degrees in EE at an angular velocity of 2rads(-1). A directive scaled RM of 60 degrees with visual feedback was performed in a sitting position, with the right forearm fixed to the lever arm in horizontal plane above protractor. Surface electromyographic activity (EMG) was recorded from the biceps brachii (BB) and triceps brachii (TB) muscles. Maximal isokinetic eccentric and concentric tests and RM test …
Assessment of Neuromuscular Function After Different Strength Training Protocols Using Tensiomyography
2015
The purpose of the study was to analyze tensiomyography (TMG) sensitivity to changes in muscle force and neuromuscular function of the muscle rectus femoris (RF) using TMG muscle properties after 5 different lower-limb strength training protocols (multiple sets; DS = drop sets; eccentric overload; FW = flywheel; PL = plyometrics). After baseline measurements, 14 male strength trained athletes completed 1 squat training protocol per week over a 5-week period in a randomized controlled order. Maximal voluntary isometric contraction (MVIC), TMG measurements of maximal radial displacement of the muscle belly (Dm), contraction time between 10 and 90% of Dm (Tc), and mean muscle contraction veloc…
Corticospinal Modulations during Motor Imagery of Concentric, Eccentric, and Isometric Actions
2019
PURPOSE It is not known yet whether the neurophysiological specificity of eccentric, concentric, and isometric contractions can also be observed when these are mentally simulated. Therefore, our aim was to assess corticospinal excitability during motor imagery (MI) of different contraction types and to test whether a passive movement during MI could have additional effects. METHODS Twelve young participants imagined contractions of the wrist flexors, firstly with the arm motionless (static mode) and second, with a congruent passive movement (wrist extension during eccentric MI and wrist flexion during concentric MI). Motor-evoked potentials (MEP) and H-reflexes were elicited in flexor carpi…
Changes in cortico-spinal excitability following uphill versus downhill treadmill exercise
2017
International audience; An acute bout of aerobic exercise induces neuroplasticity in the motor cortex. Moreover, paired associative stimulation (PAS) is known to induce neuroplasticity in M1. However, the possible influence of the type of exercise on the neuroplastic changes remains unknown. The present study investigated the effects of two different modes of muscle contraction produced during locomotor exercise on changes in corticospinal (CS) excitability. Subjects performed two 30-min treadmill exercises at an intensity corresponding to 60% of their maximal heart rate with either a +10% (uphill) or -10% (downhill) slope. These exercises were followed or not by paired associative stimulat…