scholarly journals Core Stability and Electromyographic Activity of the Trunk Musculature in Different Woman’s Sports

2020 ◽  
Vol 12 (23) ◽  
pp. 9880
Author(s):  
Paula Esteban-García ◽  
Jacobo Á. Rubio-Arias ◽  
Javier Abián-Vicen ◽  
Jorge Sánchez-Infante ◽  
José Fernando Jiménez-Díaz
Keyword(s):  
Body Composition ◽  
Maximum Voluntary Contraction ◽  
Sport Performance ◽  
Voluntary Contraction ◽  
Trunk Muscle ◽  
Core Stability ◽  
Electromyographic Activity ◽  
Flexor Muscles ◽  
Volleyball Players ◽  
Rhythmic Gymnasts

Volleyball players and gymnasts need strength training to achieve their optimum sport performance. The aims of this study were to describe body composition, strength, performance, and characteristics of trunk muscle activation in volleyball players and gymnasts, and to analyze the differences between the sports. The sample consisted of 40 female athletes: rhythmic gymnasts (n = 24; age 13.95 ± 2.77 years) and volleyball players (n = 16; age 19.81 ± 5.55 years). Body composition, maximum voluntary contraction (MVC) of isometric tests in an isokinetic dynamometer, McGill core endurance test, and surface electromyography (EMGrms) of the trunk muscle during the McGill test and isometric tests were recorded. Rhythmic gymnasts presented lower body composition values than volleyball players (p < 0.05). The volleyball players presented higher isometric strength than rhythmic gymnasts in terms of MVC in trunk flexion (p < 0.05, d = 1.3) and trunk extension (p < 0.001, d = 1.3). EMGrms from the rhythmic gymnasts were greater for trunk flexor muscles (p < 0.01, d = 0.7) and trunk extensor muscles (p < 0.001, d = 1.3) during McGill endurance tests compared to the volleyball players. In the isometric test, EMGrms from the rhythmic gymnasts were greater for trunk flexor muscles in flexion (p < 0.01, d = 0.9) and extension tests (p < 0.05, d = 0.7). In conclusion, the volleyball players exhibited higher peak strength, despite the fact that the gymnasts showed greater muscle activity during the maximum voluntary contraction.

FORCE SUMMATION AND TWITCH POTENTIATION CAPACITY IN HUMAN ANKLE PLANTAR- AND DORSI-FLEXOR MUSCLES

2014 ◽  
Vol 17 (04) ◽  
pp. 1450015
Author(s):  
Yoichi Ohta ◽  
Kengo Yotani
Keyword(s):  
Muscle Function ◽  
Pulse Train ◽  
Maximum Voluntary Contraction ◽  
Voluntary Contraction ◽  
Twitch Potentiation ◽  
Flexor Muscles ◽  
Human Ankle ◽  
Before And After ◽  
Isometric Torque ◽  
Plantar Flexor Muscles

Purpose: The present study aimed to clarify inter-individual correlation between the magnitudes of force summation and the post-activation potentiation (PAP), in human ankle plantar- and dorsi-flexor muscles. Methods: We analyzed 10 male participants plantar-flexor muscles and the 12 male participants dorsi-flexor muscles using a database from a previous study. Before and after maximum voluntary contraction, we measured the amount of isometric torque evoked by a single, double- and triple-pulse train stimulus. Results: The magnitude of PAP was significantly positively correlated with the magnitude of force summation in both the plantar- and dorsi-flexor muscles. Conclusions: The present study confirmed the correlation between the magnitudes of force summation and PAP in human ankle plantar- and dorsi-flexor muscles. This suggests that muscle characteristics affecting the force summation capacity depend on the PAP, to some degree. These results suggest that the combination of both parameters might enhance the usefulness of evaluating changes in muscle function using intrinsic contractile properties.

scholarly journals Crossfit Practice: An Electromyographic Analysis of Masticatory Muscles

2020 ◽  
Author(s):  
Nayara Soares da Silva ◽  
Marcelo Palinkas ◽  
Evandro Marianetti Fioco ◽  
Edson Donizetti Verri ◽  
Saulo César Vallin Fabrin ◽  
...  
Keyword(s):  
Maximum Voluntary Contraction ◽  
Masticatory Muscles ◽  
Voluntary Contraction ◽  
Control Group ◽  
Electromyographic Activity ◽  
Physical Conditioning ◽  
Striated Muscles ◽  
Functional Changes ◽  
Significant Difference ◽  
The Impact

Abstract Background: CrossFit is a regular high-intensity physical conditioning exercise for skeletal striated muscles, which promotes functional changes in the human body. The aim of this study was to investigate the impact of CrossFit exercise on the electromyographic activity of the masseter and temporalis muscles. Methods: Forty participants were divided into two groups: athletes who practiced CrossFit (n=20) and controls who did not practice sports (n=20). The electromyographic activities of the masseter and temporalis muscles were measured using mandibular tasks at rest, protrusion, right laterality, left laterality, and dental clenching in maximum voluntary contraction and habitual chewing of peanuts and raisins. Both the groups were matched for age, sex, and body mass index. The data were analyzed using the t-test with a 5% significance level. Results: Reduced electromyographic activities were found in all mandibular tasks in the CrossFit group than in the control group, with a significant difference for the right masseter (p=0.01), left masseter (p=0.001), and left temporal muscles (p=0.001) at mandibular rest; right (p=0.001) and left (p=0.001) masseter in chewing of peanuts. Conclusion: The results of this study suggest that CrossFit promotes positive changes in electromyographic activity of the masticatory muscles, especially in the mandibular rest and chewing of hard food. CrossFit exercise practiced within the appropriate technical protocols improves masticatory muscle function.

scholarly journals Effect of Breast Cancer Treatment on the Stomatognathic System

2018 ◽  
Vol 29 (4) ◽  
pp. 368-373
Author(s):  
Danilo Stefani Esposto ◽  
Marcelo Palinkas ◽  
Ligia Maria Napolitano Gonçalves ◽  
Paulo Batista de Vasconcelos ◽  
Vânia Tie Koga Ferreira ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Standard Deviation ◽  
Maximum Voluntary Contraction ◽  
Muscle Thickness ◽  
Voluntary Contraction ◽  
Bite Force ◽  
Electromyographic Activity ◽  
Average Standard Deviation ◽  
Functional Changes ◽  
Unilateral Mastectomy

Abstract Breast cancer is the most common cancer affecting women in the world and provides functional changes in the human body. Evaluate women submitted to unilateral mastectomy, through electromyographic activity (mandibular rest, right and left laterality, protrusion, maximum voluntary contraction with and without Parafilm, habitual and non-habitual mastication) and thickness (rest and maximum voluntary contraction) of the right temporal muscle (RT), left temporal (LT), right masseter (RM) and left masseter (LM), also the molar bite force (right and left) and compare the data with healthy women. Material and Methods: 32 women were divided into two groups: unilateral mastectomy group (MG), average ± standard deviation 56.50±14.50 years (n=16) and without the disease group (CG), average ± standard deviation 56.56±14.15 years (n=16). The normalized electromyographic data, muscle thickness and maximal molar bite force were tabulated and submitted to statistical analysis (SPSS 21.0; student t test, p≤0.05). Significant statistical differences between MG and CG were found in right laterality, for RM (p=0.02); left laterality, for LT (p=0.01); chewing with peanuts, for RM (p=0.04); chewing with raisins, for LM (p=0.04) and right molar bite force (p=0.03). There was no statistically significant difference between MG and CG for muscle thickness. The results of this study suggest that women undergoing unilateral mastectomy may present functional changes, with emphasis on muscular hyperactivity, lower masticatory efficiency and lower maxillary bite force.

ATP synthesis and proton handling in muscle during short periods of exercise and subsequent recovery

2003 ◽  
Vol 94 (6) ◽  
pp. 2391-2397 ◽  
Author(s):  
David Bendahan ◽  
Graham J. Kemp ◽  
Magali Roussel ◽  
Yann Le Fur ◽  
Patrick J. Cozzone
Keyword(s):  
Maximum Voluntary Contraction ◽  
Lactate Production ◽  
Atp Synthesis ◽  
Voluntary Contraction ◽  
Intracellular Water ◽  
Resonance Spectroscopy ◽  
Proton Production ◽  
Finger Flexion ◽  
Flexor Muscles ◽  
Finger Flexor Muscles

We used31P-magnetic resonance spectroscopy to study proton buffering in finger flexor muscles of eight healthy men (25–45 yr), during brief (18-s) voluntary finger flexion exercise (0.67-Hz contraction at 10% maximum voluntary contraction; 50/50 duty cycle) and 180-s recovery. Phosphocreatine (PCr) concentration fell 19 ± 2% during exercise and then recovered with half time = 0.24 ± 0.01 min. Cell pH rose by 0.058 ± 0.003 units during exercise as a result of H+ consumption by PCr splitting, which (assuming no lactate production or H+ efflux) implies a plausible non-Pi buffer capacity of 20 ± 3 mmol · l intracellular water−1 · pH unit−1. There was thus no evidence of significant glycogenolysis to lactate during exercise. Analysis of PCr kinetics as a classic linear response suggests that oxidative ATP synthesis reached 48 ± 2% of ATP demand by the end of exercise; the rest was met by PCr splitting. Postexercise pH recovery was faster than predicted, suggesting “excess proton” production, with a peak value of 0.6 ± 0.2 mmol/l intracellular water at 0.45 min of recovery, which might be due to, e.g., proton influx driven by cellular alkalinization, or a small glycolytic contribution to PCr resynthesis in recovery.

scholarly journals External torque as a factor to modify load in abdominal curl-up exercises

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
Alicja Rutkowska-Kucharska ◽  
Agnieszka Szpala
Keyword(s):  
External Force ◽  
Maximum Voluntary Contraction ◽  
Voluntary Contraction ◽  
Emg Activity ◽  
Electromyographic Activity ◽  
Upper Limbs ◽  
External Torque ◽  
Lever Arm ◽  
Emg Signal ◽  
Ca 50

SummaryStudy aim: the aim of our study was to evaluate electromyography (EMG) activity in exercises where the load to the muscles is determined by the external torque. In a part of the exercises, we changed the value of the external force, while in the other we modified the length of the lever arm at which the force was applied.Material and methods: the study was carried out on a group of 12 subjects (21 ± 2 years, 61 ± 4.8 mass, 172 ± 5 cm height). Electromyographic activity of the rectus abdominis (RA) muscle was evaluated by recording the EMG signal. The length of the lever arm of the external force was changed by using four different positions of the upper limbs, whereas the magnitude of the external force was changed through adding the weights of 0.5, 1.0, and 1.5 kg. The data recorded were normalized with respect to EMG activity measured under maximum voluntary contraction (MVC) conditions.Results: it was found that the change of the lever arm at which the force was applied (any change in the position of the upper limbs) causes a change in EMG activity in each part of the RA muscle from ca. 50% to ca. 100% MVC (p < 0.001). Further, the change in the external load changes statistically significantly the EMG activity only in the left upper part of the RA muscle (p < 0.05).Conclusions: activity in the RA muscle that increased for longer lever arms of the external force, offers opportunities for changing the load used during the exercise in a manner that is safe for the vertebral column.

scholarly journals Electromyographic activity in patient with an inferior implant/tooth-supported overdenture: Clinical Case Report.

2016 ◽  
Vol 19 (2) ◽  
pp. 139
Author(s):  
Caroline Cotes ◽  
José Benedito Oliveira Amorim ◽  
Vanessa Macedo ◽  
Estevao Kimpara ◽  
Tarcísio Paes-Junior
Keyword(s):  
Case Report ◽  
Clinical Case ◽  
Good Condition ◽  
Maximum Voluntary Contraction ◽  
Voluntary Contraction ◽  
Electromyographic Activity ◽  
Masticatory Efficiency ◽  
Pre Treatment ◽  
Electrical Activities ◽  
Viable Treatment

<p>Clinicians can find patients with one mandibular remaining tooth, and it is difficult to decide if the tooth has to be removed. When a clinician decide to maintaining the tooth, it is common to feel doubts about masticatory load distribution divided between the tooth and implant. This paper reports a clinical case of patient with an implant/tooth-supported overdenture and elucidates the masticatory efficiency by electromyography activity analysis. The objective of this case report was to describe a clinical case of a patient with an implant/tooth-supported overdenture and to discuss the muscle response to this treatment. Electrical activities of the masseter and anterior temporal surfaces at maximum voluntary contraction were evaluated by electromyography during pre-treatment, immediately post-treatment, 15 and 60 days after installation. When patient has one remaining tooth in good condition, the implant/tooth-supported overdenture can be recommended, to preserve the periodontal ligament and proprioception, and to minimize bone loss. Electromyography analysis showed that implant/tooth-supported overdenture is a viable treatment alternative, in muscular standpoint, when the patient has a remaining tooth with good osseous support.</p>

Surface Electromyography of the Internal and External Oblique Muscles During Isometric Tasks Targeting the Lateral Trunk

2020 ◽  
pp. 1-6
Author(s):  
Allison L. Kinney ◽  
Matthew Giel ◽  
Brady Harre ◽  
Kyle Heffner ◽  
Timothy McCullough ◽  
...  
Keyword(s):  
Surface Electromyography ◽  
Muscle Activation ◽  
Maximum Voluntary Contraction ◽  
Voluntary Contraction ◽  
Trunk Muscle ◽  
Muscle Performance ◽  
Trunk Muscles ◽  
The Novel ◽  
Rehabilitation Programs ◽  
Hip Abduction

Context: Tasks that activate the lateral trunk muscles are clinically relevant in athletic and rehabilitation programs. However, no electromyography studies have compared tasks aimed at lateral trunk muscle activation. Objective: To compare the activation magnitudes of the internal and external obliques between 4 tasks targeting recruitment of the lateral trunk muscles, including the proposal of a novel assessment. Design: Comparative laboratory study. Setting: University-based biomechanics laboratory. Participants: Sixty-three participants (35 females, age = 23.6 [2.0] y, height = 1.72 [0.10] m, mass = 70.7 [14.4] kg, body mass index = 23.6 [2.86] kg/m2). Intervention(s): Surface electromyography data were recorded bilaterally from the internal and external obliques while the participants performed 2 maximum voluntary contraction tasks followed by 4 isometric tasks. The isometric tasks included feet-elevated side-supported, trunk-elevated side-unsupported, lateral plank, and side-lying hip abduction. Main Outcome Measures: Maximum voluntary contraction-normalized and integrated muscle activities were calculated for targeted and nontargeted muscles in each task. A side-by-task analysis of variance with Bonferroni correction was conducted. Results: The trunk-elevated side-unsupported task strongly activated the internal (199% maximum voluntary contraction) and external (103%) oblique muscles. The feet-elevated side-supported task strongly activated the internal obliques (205%) but not the external obliques (55%). The lateral plank task successfully activated the internal (107%) and external (72%) obliques, but not at the highest levels of the tested tasks. The side-lying hip abduction task was the least effective at activating either the internal (48%) or external (20%) obliques. Conclusions: We recommend the novel trunk-elevated side-unsupported task for assessing lateral trunk muscle performance. For independent exercise, we recommend the lateral plank task, unless arm or shoulder pathologies are present, whereby the feet-elevated side-supported task may be favorable.

Isometric Contraction of Arm Flexor Muscles as a Method of Evaluating Cardiac Vagal Tone in Man

1997 ◽  
Vol 92 (2) ◽  
pp. 175-180 ◽  
Author(s):  
M. Al-Ani ◽  
K. Robins ◽  
A. H. Al-Khalidi ◽  
J. Vaile ◽  
J. Townend ◽  
...  
Keyword(s):  
Heart Rate ◽  
Isometric Contraction ◽  
Maximum Voluntary Contraction ◽  
Young Male ◽  
Vagal Tone ◽  
Voluntary Contraction ◽  
Respiratory Cycle ◽  
Cardiac Vagal Tone ◽  
Flexor Muscles ◽  
Voluntary Contractions

1. We have previously shown that brief voluntary isometric contractions of upper arm flexor muscles performed for one respiratory cycle elicit a significant decrease in the R—R interval. The present study was designed to determine if similar changes are produced by non-voluntary electrically evoked contractions and, if so, to establish the consistency and repeatability of the associated changes in the R—R interval. 2. The heart rate (R—R interval) response to voluntary or non-voluntary brief isometric contraction equivalent to 40% of the maximum voluntary contraction was studied in 10 healthy young male subjects during controlled ventilation at supine rest. 3. The absolute values of R—R intervals occurring in any one of 10 arbitrary phases of a respiratory cycle were measured and plotted by a computer. 4. Both voluntary and non-voluntary contractions elicited similar changes in heart rate and R—R interval, which were greater during expiration than during inspiration. 5. This confirms our previous finding that the magnitude of the R—R interval changes, with brief isometric contraction, is positively related to the degree of cardiac vagal tone. 6. Analysis of the variability between repeated tests initiated in either inspiration or expiration revealed that there was significantly less variability with the electrically induced contraction. 7. It was concluded that electrically induced contractions of 40% maximal voluntary contraction are a viable alternative to voluntary contractions and provide a more controllable means of measuring cardiac vagal withdrawal.

scholarly journals Effect of Computer Keyboard Slope on Wrist Position and Forearm Electromyography of Typists Without Musculoskeletal Disorders

2003 ◽  
Vol 83 (9) ◽  
pp. 816-830 ◽  
Author(s):  
Guy G Simoneau ◽  
Richard W Marklin ◽  
Joseph E Berman
Keyword(s):  
Carpal Tunnel ◽  
Physical Therapists ◽  
Maximum Voluntary Contraction ◽  
Slope Angle ◽  
Voluntary Contraction ◽  
Emg Activity ◽  
Electromyographic Activity ◽  
Wrist Extension ◽  
Computer Keyboard ◽  
Downward Slope

Background and Purpose. Positioning a computer keyboard with a downward slope reduces wrist extension needed to use the keyboard and has been shown to decrease pressure in the carpal tunnel. However, whether a downward slope of the keyboard reduces electromyographic (EMG) activity of the forearm muscles, in particular the wrist extensors, is not known. Subjects and Methods. Sixteen experienced typists participated in this study and typed on a conventional keyboard that was placed on slopes at angles of 7.5, 0, −7.5, and −15 degrees. Electromyographic activity of the extensor carpi ulnaris (ECU), flexor carpi ulnaris (FCU), and flexor carpi radialis (FCR) muscles was measured with surface electrodes, while the extension and ulnar deviation angles of the right and left wrists were measured with electrogoniometers. Results. Wrist extension angle decreased from approximately 12 degrees of extension while typing on a keyboard with a 7.5-degree slope to 3 degrees of flexion with the keyboard at a slope of −15 degrees. Although the differences were in the range of 1% to 3% of maximum voluntary contraction (MVC), amplitude probability distribution function (APDF) of root-mean-square EMG data points from the ECU, FCU, and FCR muscles varied across keyboard slopes. Discussion and Conclusion. Wrist extension decreased as the keyboard slope decreased. Furthermore, a slight decrease in percentage of MVC of the ECU muscle was noted as the keyboard slope decreased. Based on biomechanical modeling and published work on carpal tunnel pressure, both of these findings appear to be positive with respect to comfort and fatigue, but the exact consequences of these findings on the reduction or prevention of injuries have yet to be determined. The results may aid physical therapists and ergonomists in their evaluations of computer keyboard workstations and in making recommendations for interventions with regard to keyboard slope angle.

Trunk muscle activation during moderate- and high-intensity running

2009 ◽  
Vol 34 (6) ◽  
pp. 1008-1016 ◽  
Author(s):  
David G. Behm ◽  
Dario Cappa ◽  
Geoffrey A. Power
Keyword(s):  
Muscle Activation ◽  
Maximum Voluntary Contraction ◽  
Voluntary Contraction ◽  
Trunk Muscle ◽  
Erector Spinae ◽  
Emg Activity ◽  
Emg Signal ◽  
Extension Activity ◽  
Exercise Type ◽  
Main Effects

Time constraints are cited as a barrier to regular exercise. If particular exercises can achieve multiple training functions, the number of exercises and the time needed to achieve a training goal may be decreased. It was the objective of this study to compare the extent of trunk muscle electromyographic (EMG) activity during running and callisthenic activities. EMG activity of the external obliques, lower abdominals (LA), upper lumbar erector spinae (ULES), and lumbosacral erector spinae (LSES) was monitored while triathletes and active nonrunners ran on a treadmill for 30 min at 60% and 80% of their maximum heart rate (HR) reserve, as well as during 30 repetitions of a partial curl-up and 3 min of a modified Biering-Sørensen back extension exercise. The mean root mean square (RMS) amplitude of the EMG signal was monitored over 10-s periods with measures normalized to a maximum voluntary contraction rotating curl-up (external obliques), hollowing exercise (LA), or back extension (ULES and LSES). A main effect for group was that triathletes had greater overall activation of the external obliques (p < 0.05), LA (p = 0.01), and LSES (p < 0.05) than did nonrunners. Main effects for exercise type showed that the external obliques had less EMG activity during 60% and 80% runs, respectively, than with the curl-ups (p = 0.001). The back extension exercise provided less ULES (p = 0.009) and LSES (p = 0.0001) EMG activity than the 60% and 80% runs, respectively. In conclusion, triathletes had greater trunk activation than nonrunners did while running, which could have contributed to their better performance. Back-stabilizing muscles can be activated more effectively with running than with a prolonged back extension activity. Running can be considered as an efficient, multifunctional exercise combining cardiovascular and trunk endurance benefits.

Sign in / Sign up

Export Citation Format

Share Document