Influence of preceding muscle activity on perceptually guided force production during superimposed ballistic contraction

2020 ◽  
Vol 222 ◽  
pp. 112933 ◽  
Author(s):  
Takeshi Miyamoto ◽  
Tomohiro Kizuka ◽  
Seiji Ono
Keyword(s):  
Muscle Activity ◽  
Force Production ◽  
Ballistic Contraction

Alternate muscle activity observed between knee extensor synergists during low-level sustained contractions

2002 ◽  
Vol 93 (2) ◽  
pp. 675-684 ◽  
Author(s):  
Motoki Kouzaki ◽  
Minoru Shinohara ◽  
Kei Masani ◽  
Hiroaki Kanehisa ◽  
Tetsuo Fukunaga
Keyword(s):  
Muscle Activity ◽  
Vastus Lateralis ◽  
Force Production ◽  
Knee Extensor ◽  
Rectus Femoris ◽  
Quadriceps Muscle ◽  
Knee Extension ◽  
Voluntary Contraction ◽  
Low Level ◽  
Integrated Emg

To determine quantitatively the features of alternate muscle activity between knee extensor synergists during low-level prolonged contraction, a surface electromyogram (EMG) was recorded from the rectus femoris (RF), vastus lateralis (VL), and vastus medialis (VM) in 11 subjects during isometric knee extension exercise at 2.5% of maximal voluntary contraction (MVC) for 60 min ( experiment 1). Furthermore, to examine the relation between alternate muscle activity and contraction levels, six of the subjects also performed sustained knee extension at 5.0, 7.5, and 10.0% of MVC ( experiment 2). Alternate muscle activity among the three muscles was assessed by quantitative analysis on the basis of the rate of integrated EMG sequences. In experiment 1, the number of alternations was significantly higher between RF and either VL or VM than between VL and VM. Moreover, the frequency of alternate muscle activity increased with time. In experiment 2, alternating muscle activity was found during contractions at 2.5 and 5.0% of MVC, although not at 7.5 and 10.0% of MVC, and the number of alternations was higher at 2.5 than at 5.0% of MVC. Thus the findings of the present study demonstrated that alternate muscle activity in the quadriceps muscle 1) appears only between biarticular RF muscle and monoarticular vasti muscles (VL and VM), and its frequency of alternations progressively increases with time, and 2) emerges under sustained contraction with force production levels ≤5.0% of MVC.

scholarly journals Sprint Specificity of Isolated Hamstring-Strengthening Exercises in Terms of Muscle Activity and Force Production

2021 ◽  
Vol 2 ◽  
Author(s):  
Caroline Prince ◽  
Jean-Benoît Morin ◽  
Jurdan Mendiguchia ◽  
Johan Lahti ◽  
Kenny Guex ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Production Capacity ◽  
Force Production ◽  
Electromyographic Activity ◽  
Horizontal Force ◽  
Hamstring Muscle ◽  
Strengthening Exercises ◽  
Hip Flexion ◽  
Production Capacities ◽  
Hip Extension

To train hamstring muscle specifically to sprint, strengthening programs should target exercises associated with horizontal force production and high levels of hamstring activity. Therefore, the objectives of this study were to analyze the correlation between force production capacities during sprinting and hamstring strengthening exercises, and to compare hamstring muscle activity during sprinting and these exercises. Fourteen track and field regional level athletes performed two maximal 50-m sprints and six strengthening exercises: Nordic hamstring exercises without and with hip flexion, Upright-hip-extension in isometric and concentric modalities, Standing kick, and Slide-leg-bridge. The sprinting horizontal force production capacity at low (F0) and high (V0) speeds was computed from running velocity data. Hamstring muscle performances were assessed directly or indirectly during isolated exercises. Hamstring muscle electromyographic activity was recorded during all tasks. Our results demonstrate substantially large to very large correlations between V0 and performances in the Upright-hip-extension in isometric (rs = 0.56; p = 0.040), Nordic hamstring exercise without hip flexion (rs = 0.66; p = 0.012) and with 90° hip flexion (rs = 0.73; p = 0.003), and between F0 and Upright-hip-extension in isometric (rs = 0.60; p = 0.028) and the Nordic hamstring exercise without hip flexion (rs = 0.59; p = 0.030). However, none of the test exercises activated hamstring muscles more than an average of 60% of the maximal activation during top-speed sprinting. In conclusion, training programs aiming to be sprint-specific in terms of horizontal force production could include exercises such as the Upright-hip-extension and the Nordic hamstring exercise, in addition to maximal sprinting activity, which is the only exercise leading to high levels of hamstring muscle activity.

scholarly journals Phase-Dependent Modulation of Auxiliary Swimmeret Muscle Activity in the Equilibrium Reactions of the Norway Lobster, Nephrops Norvegicus L

1986 ◽  
Vol 126 (1) ◽  
pp. 157-179
Author(s):  
DOUGLAS M. NEIL ◽  
JALEEL A. MIYAN
Keyword(s):  
Muscle Activity ◽  
Force Production ◽  
Pattern Generator ◽  
Nephrops Norvegicus ◽  
Motor Activation ◽  
Norway Lobster ◽  
Equilibrium Reactions ◽  
Body Roll ◽  
Muscle Groups ◽  
Stimulation Of

1. The activity of swimmeret muscles of the lobster Nephrops norvegicus during beating in the upright and tilted animal has been examined. The responses to tilt are produced primarily by stimulation of the statocysts. 2. The anatomy of the swimmeret muscles is described. Although essentially similar to previous descriptions, important new aspects are presented. 3. The arrangement of the main powerstroke and returnstroke muscle groups in relation to the peg-and-hook articulation of the swimmeret produces a segregation of action, with different muscles contributing progressively to force production. 4. The auxiliary muscles of the basipodite, M9, M10 and M13 act to twist the swimmeret laterally. The auxiliary muscle Ml 1–12–14–15 acts to maintain a rearward powerstroke. 5. The innervation of swimmeret muscles and the location of their motoneurone cell bodies in the abdominal ganglia have been revealed by cobalt staining. There is a clear segregation of powerstroke and returnstroke motoneurones. Intraganglionic fibre tracts as well as four interganglionic fibres are identified. 6. Intracellular studies on the twister muscles show that M9 receives at least three excitatory units, and M10 at least six. No inhibitory activity was ever recorded in these muscles. M9 and the medial bundle of M10 receive tonic excitatory inputs, while the lateral bundle of M10 receives phasic inputs and is normally silent in the absence of lateral beating. 7. In the absence of swimmeret beating, body roll about the long axis induces tonic motor activation of the lateral twister muscles (M9 and M10) and the returnstroke muscles in the swimmerets on the side tilted upwards. 8. When beating occurs it is predominantly in the swimmerets tilted upwards, and there is an entrainment of phasic activity in M9, M10 and M13 to the powerstroke phase of the beats. Tonic units to the returnstroke muscle remain unaffected. 9. The results are discussed with particular reference to the interaction of descending statocyst information with the central pattern generator for swimmeret beating. Note:

The influence of circadian rhythm on muscle activity and efficient force production during cycling at different pedal rates

2007 ◽  
Vol 17 (2) ◽  
pp. 176-183 ◽  
Author(s):  
N. Bessot ◽  
S. Moussay ◽  
J.P. Clarys ◽  
A. Gauthier ◽  
B. Sesboüé ◽  
...  
Keyword(s):  
Circadian Rhythm ◽  
Muscle Activity ◽  
Force Production

Mutability of Bifunctional Thigh Muscle Activity in Pedaling due to Contralateral Leg Force Generation

2002 ◽  
Vol 88 (3) ◽  
pp. 1308-1317 ◽  
Author(s):  
S. A. Kautz ◽  
D. A. Brown ◽  
H.F.M. Van der Loos ◽  
F. E. Zajac
Keyword(s):  
Muscle Activity ◽  
Isometric Force ◽  
Force Production ◽  
Rectus Femoris ◽  
Force Generation ◽  
Thigh Muscle ◽  
Work Output ◽  
Thigh Muscles ◽  
Sensorimotor Activity ◽  
Bifunctional Muscle

Locomotion requires uninterrupted transitions between limb extension and flexion. The role of contralateral sensorimotor signals in executing smooth transitions is little understood even though their participation is crucial to bipedal walking. However, elucidating neural interlimb coordinating mechanisms in human walking is difficult because changes to contralateral sensorimotor activity also affect the ipsilateral mechanics. Pedaling, conversely, is ideal for studying bilateral coordination because ipsilateral mechanics can be independently controlled. In pedaling, the anterior and posterior bifunctional thigh muscles develop needed anterior and posterior crank forces, respectively, to dominate the flexion-to-extension and extension-to-flexion transitions. We hypothesized that contralateral sensorimotor activity substantially contributes to the appropriate activation of these bifunctional muscles during the limb transitions. Bilateral pedal forces and surface electromyograms (EMGs) from four thigh muscles were collected from 15 subjects who pedaled with their right leg against a right-crank servomotor, which emulated the mechanical load experienced in conventional two-legged coupled-crank pedaling. In one pedaling session, the contralateral (left) leg pseudo-pedaled (i.e., EMG activity and pedal forces were pedaling-like, but pedal force was not allowed to affect crank rotation). In other sessions, the mechanically decoupled contralateral leg was first relaxed and then produced rhythmic isometric force trajectories during either leg flexion or one of the two limb transitions of the pedaling leg. With contralateral force production in the extension-to-flexion transition (predominantly by the hamstrings), rectus femoris activity and work output increased in the pedaling leg during its flexion-to-extension transition, which occurs simultaneously with contralateral extension-to-flexion in conventional pedaling. Similarly, with contralateral force production in the other transition (i.e., flexion-to-extension; predominantly by rectus femoris), hamstrings activity and work output increased in the pedaling leg during its extension-to-flexion transition. Therefore rhythmic isometric force generation in the contralateral leg supported the ongoing bifunctional muscle activity and resulting work output in the pedaling leg. The results suggest that neural interlimb coordinating mechanisms fine-tune bifunctional muscle activity in rhythmic lower-limb tasks to ensure limb flexion/extension transitions are executed successfully.

scholarly journals Advanced Rock Climbers Exhibit Greater Finger Force and Resistance to Fatigue Compared to Novices During Treadwall Climbing

2020 ◽  
Author(s):  
Philip F. Ferrara ◽  
James Becker ◽  
John G. Seifert
Keyword(s):  
Muscle Activity ◽  
Force Plate ◽  
Force Production ◽  
Median Frequency ◽  
Finger Force ◽  
Flexor Muscle ◽  
Significant Group ◽  
Maximum Voluntary Isometric Contraction ◽  
Before And After ◽  
Flexor Digitorum

AbstractBackgroundThe purpose of the study was to investigate the effects of rock climbing experience on time to fatigue (TTF), finger flexor force production relative to body weight (REL FP), and changes in finger flexor muscle activity during tread wall climbing.MethodsEight advanced and seven novice sport rock climbers performed a climbing protocol on a treadwall system. The protocol consisted of climbing for six 5-minute intervals or until voluntary failure. A mounted force plate was used to measure finger force production before and after the climbing protocol. Subjects performed a 20-second maximum voluntary isometric contraction (MVIC) against the force plate with the dominant and non-dominant fingertips in a common climbing hand configuration known as a half crimp. Muscle activity was monitored with electromyographic electrodes placed bilaterally over the subject’s flexor digitorum superficialis. Median frequency (MF) and root mean square (RMS) were analyzed. The treadwall was set at a difficulty of 9 IRCRA/5.9 YDS. It rotated at 7 m/min and was fixed at 7° overhanging.ResultsSignificant group differences were observed in subject characteristics, TTF (30±0 vs. 25.7±3.6 min), REL FP (5.6±1.2 vs. 3.2±0.9 N/kg BW), ΔFP (+1.5±12.3% vs. -31±16%), and ΔMF (+6.3±22.4% vs. -17.6±10.9%).ConclusionThe results of this study demonstrate that advanced climbers possess greater finger flexor force production and resistance to fatigue compared to novices during bouts of climbing on a treadwall system. This may be attributed to physiological changes due to years of training, such as metabolic adaptations and oxygenation capacity in the forearm musculature.

scholarly journals Spatial Reorganization of Myoelectric Activities in Extensor Digitorum for Sustained Finger Force Production

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 555
Author(s):  
Zhixian Gao ◽  
Shangjie Tang ◽  
Xiaoying Wu ◽  
Qiang Fu ◽  
Xingyu Fan ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Electrode Array ◽  
Force Production ◽  
Voluntary Contraction ◽  
Extensor Digitorum ◽  
Topographic Maps ◽  
Regulation Mechanism ◽  
Force Output ◽  
Sustained Contraction ◽  
Spatial Reorganization

The study aims to explore the spatial distribution of multi-tendinous muscle modulated by central nervous system (CNS) during sustained contraction. Nine subjects were recruited to trace constant target forces with right index finger extension. Surface electromyography (sEMG) of extensor digitorum (ED) were recorded with a 32-channel electrode array. Nine successive topographic maps (TM) were obtained. Pixel wise analysis was utilized to extract subtracted topographic maps (STM), which exhibited inhomogeneous distribution. STMs were characterized into hot, warm, and cool regions corresponding to higher, moderate, and lower change ranges, respectively. The relative normalized area (normalized to the first phase) of these regions demonstrated different changing trends as rising, plateauing, and falling over time, respectively. Moreover, the duration of these trends were found to be affected by force level. The rising/falling periods were longer at lower force levels, while the plateau can be achieved from the initial phase for higher force output (45% maximal voluntary contraction). The results suggested muscle activity reorganization in ED plays a role to maintain sustained contraction. Furthermore, the decreased dynamical regulation ability to spatial reorganization may be prone to induce fatigue. This finding implied that spatial reorganization of muscle activity as a regulation mechanism contribute to maintain constant force production.

Imaging of skeletal muscle function using 18FDG PET: force production, activation, and metabolism

2001 ◽  
Vol 90 (1) ◽  
pp. 329-337 ◽  
Author(s):  
George P. Pappas ◽  
Eric W. Olcott ◽  
John E. Drace
Keyword(s):  
Skeletal Muscle ◽  
Muscle Activity ◽  
Fdg Pet ◽  
Biceps Brachii ◽  
Plantar Flexion ◽  
Force Production ◽  
Elbow Flexion ◽  
Skeletal Muscle Function ◽  
Fdg Uptake ◽  
18Fdg Pet

The purpose of this study was to determine whether [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) can be used to evaluate muscle force production, create anatomic images of muscle activity, and resolve the distribution of metabolic activity within exercising skeletal muscle. Seventeen subjects performed either elbow flexion, elbow extension, or ankle plantar flexion after intravenous injection of FDG. PET imaging was performed subsequently, and FDG uptake was measured in skeletal muscle for each task. A fivefold increase in resistance during elbow flexion increased FDG uptake in the biceps brachii by a factor of 4.9. Differences in relative FDG uptake were demonstrated as exercise tasks and loads were varied, permitting differentiation of active muscles. The intramuscular distribution of FDG within exercising biceps brachii varied along the transverse and longitudinal axes of the muscle; coefficients of variation along these axes were 0.39 and 0.23, respectively. These findings suggest FDG PET is capable of characterizing task-specific muscle activity and measuring intramuscular variations of glucose metabolism within exercising skeletal muscle.

Sign in / Sign up

Export Citation Format

Share Document