Search results for "Muscle activation"

2020

Limited data are available regarding strength and endurance training adaptations to occupational physical performance during deployment. This study assessed acute training-induced changes in neuromuscular (electromyography; EMG) and metabolic (blood lactate, BLa) responses during a high-intensity military simulation test (MST), performed in the beginning (PRE) and at the end (POST) of a six-month crisis-management operation. MST time shortened (145 ± 21 vs. 129 ± 16 s, −10 ± 7%, p < 0.001) during the operation. Normalized muscle activity increased from PRE to POST in the hamstring muscles by 87 ± 146% (116 ± 52 vs. 195 ± 139%EMGMVC, p < 0.001) and in the quadriceps by 54 ± 81% (26 ± 8…

Nordic walking influence on biomechanical parameters: a systematic review

2020

INTRODUCTION Nordic walking (NW) as a form of physical activity has been shown to have benefits in various domains, but little is known about the effect of NW on more specific biomechanical parameters. The purpose is to determine the impact of NW on the following parameters: walking speed/distance, muscle activation, spatiotemporal parameters, kinematics and ground reaction force. EVIDENCE ACQUISITION A literature search was carried out in different databases from October 2008 to October 2018. This review was conducted and reported in accordance with the PRISMA statement. Finally, 42 studies with a median PEDro Score of 5.5/10 were included. EVIDENCE SYNTHESIS The included studies reported …

Initiating running barefoot: Effects on muscle activation and impact accelerations in habitually rearfoot shod runners

2016

Runners tend to shift from a rearfoot to a forefoot strike pattern when running barefoot. However, it is unclear how the first attempts at running barefoot affect habitually rearfoot shod runners. Due to the inconsistency of their recently adopted barefoot technique, a number of new barefoot-related running injuries are emerging among novice barefoot runners. The aim of this study was therefore to analyse the influence of three running conditions (natural barefoot [BF], barefoot with a forced rearfoot strike [BRS], and shod [SH]) on muscle activity and impact accelerations in habitually rearfoot shod runners. Twenty-two participants ran at 60% of their maximal aerobic speed while foot strik…

Age-related muscle activation profiles and joint stiffness regulation in repetitive hopping

2011

Abstract It is well documented that increasing effort during exercise is characterized by an increase in electromyographic activity of the relevant muscles. How aging influences this relationship is a matter of great interest. In the present study, nine young and 24 elderly subjects did repetitive hopping with maximal effort as well as with 50%, 65%, 75% and 90% intensities. During hopping joint kinematics were measured together with electromyographic activity (EMG) from the soleus, gastrocnemius medialis, gastrocnemius lateralis and tibialis anterior muscles. The results showed that agonist activation increased in both age groups with increasing intensity. The highest jumping efficiency (E…

''Alterations with Movement Duration in the Kinematics of a Whole Body Pointing Movement''

2013

Casteran, Matthieu | Manckoundia, Patrick | Pozzo, Thierry | Thomas, Elizabeth; International audience; ''Our aim was to investigate how the organization of a whole body movement is altered when movement duration (MD) is varied. Subjects performed the same whole body pointing movement over long, normal and short MDs. The kinematic trajectories were then analyzed on a normalized time base. A principal components analysis (PCA) revealed that the degree of coordination between the elevation angles of the body did not change with MD. This lack of significant differences in the coordination was interesting given that small spatial and temporal differences were observed in the individual kinemati…

Potentiation of the mechanical behavior of the human skeletal muscle through prestretching

1979

Force-velocity and power-velocity curves in a vertical jump involving movements around several joints were derived from vertical ground reaction forces and knee angular velocities. The jumps were performed with weights from 10 to 160 kg added on the shoulders. The obtained curves from a semi-squatting static starting position resembled those reported for isolated muscles or single muscle groups. Vertical jumps were also performed in the conditions where the shortening of the leg extensors was preceded by prestretching of the active muscles either through a preparatory counter-movement or dropping down on the force-platform from the various heights ranging from 20 to 100 cm. Prestretching mo…

Dominant vs. nondominant arm advantage in mentally simulated actions in right handers

2013

Although plentiful data are available regarding mental states involving the dominant-right arm, the evidence for the nondominant-left arm is sparse. Here, we investigated whether right-handers can generate accurate predictions with either the right or the left arm. Fifteen adults carried out actual and mental arm movements in two directions with varying inertial resistance (inertial anisotropy phenomenon). We recorded actual and mental movement times and used the degree of their similarity as an indicator for the accuracy of motor imagery/prediction process. We found timing correspondences (isochrony) between actual and mental right arm movements in both rightward (low inertia resistance) …

Can Graduated Compressive Stockings Reduce Muscle Activity During Running?

2017

Purpose: Graduated compressive stockings (GCS) have been suggested to influence performance by reducing muscle oscillations and improving muscle function and efficiency. However, no study to date has analyzed the influence of GCS on muscle activity during running. The objective of the study was to analyze the influence of GCS on the perception of comfort and muscle activation of the main muscles of the lower leg during running. Method: Thirty-six participants ran on a treadmill with (GCS) or without (control) GCS. The running tests consisted of a 10-min warm-up followed by a 20-min intense run at 75% of the athlete’s maximal aerobic speed. Surface electromyography of the tibialis anterior, …

Muscle activation during cycling at different cadences: Effect of maximal strength capacity

2007

International audience; The purpose of this study was to examine the influence of maximal strength capacity on muscle activation, during cycling, at three selected cadences: a low cadence (50 rpm), a high cadence (110 rpm) and the freely chosen cadence (FCC). Two groups of trained cyclists were selected on the basis of the different maximal isokinetic voluntary contraction values (MVCi) of their lower extremity muscles as follow: Fmin (lower MVCi group) and Fmax (higher MVCi group). All subjects performed three 4-min cycling exercises at a power output corresponding to 80 % of the ventilatory threshold under the three cadences. Neuromuscular activity of vastus lateralis (VL), rectus femoris…

Relationship between Skin Temperature, Electrical Manifestations of Muscle Fatigue, and Exercise-Induced Delayed Onset Muscle Soreness for Dynamic Co…

2020

Delayed onset muscle soreness (DOMS) indicates the presence of muscle damage and impairs force production and control. Monitorization of DOMS is useful to improving recovery intervention plans. The magnitude of DOMS may relate to muscle fatigue, which can be monitored by surface electromyography (EMG). Additionally, growing interest has been expressed in determining whether the skin temperature over a muscle group during exercise to fatigue could be a non-invasive marker for DOMS. Here we determine whether skin temperature and manifestations of muscle fatigue during exercise are correlated and can predict DOMS after concentric&ndash