scholarly journals Guidelines for Working Heights of the Lower-Limb Exoskeleton (CEX) Based on Ergonomic Evaluations

2021 ◽  
Vol 18 (10) ◽  
pp. 5199
Author(s):  
Yong-Ku Kong ◽  
Chae-Won Park ◽  
Min-Uk Cho ◽  
Seoung-Yeon Kim ◽  
Min-Jung Kim ◽  
...  
Keyword(s):  
Lower Limb ◽  
Muscle Activity ◽  
Biceps Brachii ◽  
Erector Spinae ◽  
Whole Body ◽  
Emg Activity ◽  
Triceps Brachii ◽  
Lower Limb Exoskeleton ◽  
Upper Trapezius ◽  
Subjective Discomfort

The aim of this study was to evaluate the muscle activities and subjective discomfort according to the heights of tasks and the lower-limb exoskeleton CEX (Chairless EXoskeleton), which is a chair-type passive exoskeleton. Twenty healthy subjects (thirteen males and seven females) participated in this experiment. The independent variables were wearing of the exoskeleton (w/ CEX, w/o CEX), working height (6 levels: 40, 60, 80, 100, 120, and 140 cm), and muscle type (8 levels: upper trapezius (UT), erector spinae (ES), middle deltoid (MD), triceps brachii (TB), biceps brachii (BB), biceps femoris (BF), rectus femoris (RF), and tibialis anterior (TA)). The dependent variables were EMG activity (% MVC) and subjective discomfort rating. When wearing the CEX, the UT, ES, RF, and TA showed lower muscle activities at low working heights (40–80 cm) than not wearing the CEX, whereas those muscles showed higher muscle activities at high working heights (100–140 cm). Use of the CEX had a positive effect on subjective discomfort rating at lower working heights. Generally, lower discomfort was reported at working heights below 100 cm when using the CEX. At working heights of 100–140 cm, the muscle activity when wearing the CEX tended to be greater than when not wearing it. Thus, considering the results of this study, the use of the lower-limb exoskeleton (CEX) at a working height of 40–100 cm might reduce the muscle activity and discomfort of whole body and decrease the risk of related disorders.

scholarly journals The Effects of Bench Press Variations in Competitive Athletes on Muscle Activity and Performance

2017 ◽  
Vol 57 (1) ◽  
pp. 61-71 ◽  
Author(s):  
Atle Hole Saeterbakken ◽  
Dag-André Mo ◽  
Suzanne Scott ◽  
Vidar Andersen
Keyword(s):  
Muscle Activity ◽  
Latissimus Dorsi ◽  
Bench Press ◽  
Biceps Brachii ◽  
High Load ◽  
Emg Activity ◽  
International Level ◽  
Triceps Brachii ◽  
Competitive Athletes ◽  
And Performance

AbstractThe aim of the study was to compare the EMG activity performing 6RM competition style bench press (flat bench-wide grip) with 1) medium and narrow grip widths on a flat bench and 1) inclined and declined bench positions with a wide grip. Twelve bench press athletes competing at national and international level participated in the study. EMG activity was measured in the pectoralis major, anterior and posterior deltoid, biceps brachii, triceps brachii and latissimus dorsi. Non-significant differences in activation were observed between the three bench positions with the exception of 58.5-62.6% lower triceps brachii activation, but 48.3-68.7% greater biceps brachii activation in the inclined bench compared with the flat and declined bench position. Comparing the three grip widths, non-significant differences in activations were observed, with the exception of 25.9-30.5% lower EMG activity in the biceps brachii using a narrow grip, compared to the medium and wide grip conditions. The 6-RM loads were 5.8-11.1% greater using a medium and wide grip compared to narrow grip width and 18.5-21.5% lower in the inclined bench position compared with flat and declined. Comparing the EMG activity during the competition bench press style with either the inclined and declined bench position (wide grip) or using a narrow and medium grip (flat bench), only resulted in different EMG activity in the biceps- and triceps brachii. The 6RM loads varied with each bench press variation and we recommend the use of a wide grip on a flat bench during high load hypertrophy training to bench press athletes.

Effect of Arm Cranking Direction on EMG, Kinematic, and Oxygen Consumption Responses

2004 ◽  
Vol 20 (2) ◽  
pp. 129-143 ◽  
Author(s):  
Eadric Bressel ◽  
Gary D. Heise
Keyword(s):  
Oxygen Consumption ◽  
Muscle Activity ◽  
Biceps Brachii ◽  
Emg Activity ◽  
Half Cycle ◽  
Wrist Flexion ◽  
Triceps Brachii ◽  
Arm Cranking ◽  
Video Images ◽  
Consumption Data

The purpose of this study was to compare muscle activity, kinematic, and oxygen consumption characteristics between forward and reverse arm cranking. Twenty able-bodied men performed 5-min exercise bouts of forward and reverse arm cranking while electromyographic (EMG), kinematic, and oxygen consumption data were collected. EMG activity of biceps brachii, triceps brachii, deltoid, and infraspinatus muscles were recorded and analyzed to reflect on-time durations and amplitudes for each half-cycle (first 180° and second 180° of crank cycle). Kinematic data were quantified from digitization of video images, and oxygen consumption was calculated from expired gases. Dependent measures were analyzed with a MANOVA and follow-up univariate procedures; alpha was set at .01. The biceps brachii, deltoid, and infraspinatus muscles displayed greater on-time durations and amplitudes for select half-cycles of reverse arm cranking compared to forward arm cranking (p< 0.01). Peak wrist flexion was 9% less in reverse arm cranking (p< 0.01), and oxygen consumption values did not differ between conditions (p= 0.25). Although there were no differences in oxygen consumption and only minor differences kinematically, reverse arm cranking requires greater muscle activity from the biceps brachii, deltoid, and infraspinatus muscles. These results may allow clinicians to more effectively choose an arm cranking direction that either minimizes or maximizes upper extremity muscle activity depending on the treatment objectives.

scholarly journals Effect of Fatigue Upon Performance and Electromyographic Activity in 6-RM Bench Press

2014 ◽  
Vol 40 (1) ◽  
pp. 57-65 ◽  
Author(s):  
Roland van den Tillaar ◽  
Atle Saeterbakken
Keyword(s):  
Bench Press ◽  
Biceps Brachii ◽  
Erector Spinae ◽  
Emg Activity ◽  
Electromyographic Activity ◽  
Triceps Brachii ◽  
Antagonist Muscle ◽  
Prime Movers ◽  
And Performance ◽  
Single Set

Abstract The aim of this study was to examine the effect of fatigue during one set of 6-RM bench pressing upon the muscle patterning and performance. Fourteen resistance-trained males (age 22.5±2.0 years, stature 1.82±0.07 m, body mass 82.0±7.8 kg) conducted a 6-RM bench press protocol. Barbell kinematics and EMG activity of pectoralis major, deltoid anterior, biceps brachii, triceps brachii, rectus abdominis, oblique external and erector spinae were measured in each repetition during the 6-RM bench press. Total lifting time increased and the velocity in the ascending movement decreased (p≤0.001). However, the kinematics in the descending phase deferred: the time decreased and velocity increased during the 6-RM (p≤0.001). Generally, muscles increased their EMG amplitude during the six repetitions in the ascending movement, while only three of the seven measured muscles showed an increase over the six repetitions in the descending part in 6-RM bench pressing. It was concluded that the bench pressing performance decreased (lower barbell velocities and longer lifting times) with increasing fatigue in the 6-RM execution. Furthermore EMG increased in the prime movers and the trunk stabilizers (abdominal and spine), while the antagonist muscle (biceps) activity was not affected by fatigue during the lifting phase in a single set of 6-RM bench pressing

Shoulder Muscle Activation Levels During the Push-Up-Plus Exercise on Stable and Unstable Surfaces

2017 ◽  
Vol 26 (4) ◽  
pp. 281-286 ◽  
Author(s):  
Rafaela J.B. Torres ◽  
André L.T. Pirauá ◽  
Vinícius Y.S. Nascimento ◽  
Priscila S. dos Santos ◽  
Natália B. Beltrão ◽  
...  
Keyword(s):  
Muscle Activation ◽  
Biceps Brachii ◽  
Emg Activity ◽  
Activity Levels ◽  
Triceps Brachii ◽  
Serratus Anterior ◽  
Upper Trapezius ◽  
Unstable Surface ◽  
Hands And Feet ◽  
Push Up

The aim of this study was to evaluate the acute effect of the use of stable and unstable surfaces on electromyography (EMG) activity and coactivation of the scapular and upper-limb muscles during the push-up plus (with full protraction of the scapula). Muscle activation of anterior deltoid (AD), posterior deltoid (PD), pectoralis major, biceps brachii (BB), triceps brachii (TB), upper trapezius (UT), middle trapezius (MT), lower trapezius (LT), and serratus anterior (SA) levels and coactivation index were determined by surface EMG in 20 young men during push-up plus performed on a stable and unstable condition (2 unstable devices applied to hands and feet). The paired t test and Cohen d were used for statistical analysis. The results showed that during the execution of the push-up plus on the unstable surface an increased EMG activity of the scapular stabilizing muscles (SA, MT, and LT) was observed, while AD and PD muscles showed a decrease. During exercise execution on the unstable surface there was a higher index of coactivation of the scapular muscles (SA–MT and UT–LT pairs). No significant differences were observed in TB–BB and AD–PD pairs. These results suggest that the push-up-plus exercise associated with unstable surfaces produced greater EMG activity levels and coactivation index of the scapular stabilizing muscle. On the other hand, the use of an unstable surface does not promote the same effect for the shoulder muscles.

scholarly journals Effects of Deep Dry Needling on Tremor Severity and Functionality in Stroke: A Case Report

Healthcare ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 5
Author(s):  
José Antonio Ortín ◽  
Elisabeth Bravo-Esteban ◽  
Jaime Ibáñez ◽  
Pablo Herrero ◽  
Julio Gómez-Soriano ◽  
...  
Keyword(s):  
Inertial Sensors ◽  
Biceps Brachii ◽  
Trigger Points ◽  
Emg Activity ◽  
Pinch Strength ◽  
Dry Needling ◽  
Triceps Brachii ◽  
Post Intervention ◽  
Myofascial Trigger Points ◽  
Upper Trapezius

This study aimed to determine the effect of one session of dry needling on the severity of tremor, motor function and skills, and quality of life of a 39-year-old woman with post-stroke tremor. Myofascial trigger points (MTrP) of the following muscles were treated: extensor digitorum, flexor digitorum superficialis and profundus, brachioradialis, short head of biceps brachii, long head of triceps brachii, mid deltoid, infraspinatus, teres minor, upper trapezius, and supraspinatus. Outcomes were assessed via (i) clinical scales (activity of daily living (ADL-T24), a visual analog scale (VAS), and the Archimedes spiral), (ii) a functional test (9-Hole Peg test), and (iii) biomechanical and neurophysiological measurements (inertial sensors, electromyography (EMG), and dynamometry). The subject showed a decrease in the severity of tremor during postural (72.7%) and functional (54%) tasks after treatment. EMG activity decreased after the session and returned to basal levels 4 days after. There was an improvement post-intervention (27.84 s) and 4 days after (32.43 s) in functionality and manual dexterity of the affected limb, measured with the 9-Hole Peg test, as well as in the patient’s hand and lateral pinch strength after the treatment (26.9% and 5%, respectively), that was maintained 4 days later (15.4% and 16.7%, respectively).

Shoulder Muscle Activation Levels During Exercises With Axial and Rotational Load on Stable and Unstable Surfaces

2017 ◽  
Vol 33 (2) ◽  
pp. 118-123 ◽  
Author(s):  
Vinícius Yan Santos Nascimento ◽  
Rafaela Joyce Barbosa Torres ◽  
Natália Barros Beltrão ◽  
Priscila Soares dos Santos ◽  
André Luiz Torres Pirauá ◽  
...  
Keyword(s):  
Muscle Activation ◽  
Bench Press ◽  
Biceps Brachii ◽  
Emg Activity ◽  
Triceps Brachii ◽  
Serratus Anterior ◽  
Upper Trapezius ◽  
Unstable Surface ◽  
Lower Trapezius ◽  
Rotational Load

This study evaluated the effects of instability on the EMG activity of scapular stabilizing and upper limb muscles during exercises with axial and rotational load. Twenty male volunteers (20.9 ± 1.8 years, 174.1 ± 0.04 cm, 73.17 ± 8.77 kg) experienced in strength training participated in a crossover design. Muscle activation of anterior deltoid (AD), posterior deltoid (PD), pectoralis major (PM), biceps brachii (BB), triceps brachii (TB), upper trapezius (UT), middle trapezius (MT), lower trapezius (LT), and serratus anterior (SA) were determined on both conditions. Participants performed a single series of 10 repetitions of bench press and fly exercises on stable (bench) and unstable (proprioceptive disc) conditions at 60% of 1-RM. The Friedman test and post hoc Dunn’s indicated that the unstable condition showed greater EMG activity for AD (P = .001) and BB (P = .002) on the fly exercise, SA (P = .001) and LT (P = .048) on the bench press, and PM (P ≤ .002) on both exercises. These results show that using an unstable surface in exercises with rotational load provides superior EMG activity of the agonist muscles, while in exercise with axial load, the instability favors EMG activity of the scapular stabilizing muscles.

scholarly journals Investigating the Effects of Mental Fatigue on Resistance Exercise Performance

2021 ◽  
Vol 18 (13) ◽  
pp. 6794
Author(s):  
Denver M. Y. Brown ◽  
Amanda Farias Zuniga ◽  
Daanish M. Mulla ◽  
Divya Mendonca ◽  
Peter J. Keir ◽  
...  
Keyword(s):  
Muscle Activation ◽  
Perceived Exertion ◽  
Biceps Brachii ◽  
Experimental Manipulation ◽  
Mental Fatigue ◽  
Erector Spinae ◽  
Future Research ◽  
Dynamic Resistance ◽  
Triceps Brachii ◽  
Upper Trapezius

Mental fatigue can impart negative effects on subsequent physical performance, although the mechanisms underlying these effects are not well understood. This study examined whether mental fatigue confers negative carryover effects on the performance of a set of biceps curls, while also investigating physiological and psychological mechanisms proposed to explain the predicted effect. A randomized, cross-over design was employed. On visit 1, participants (N = 10) performed a barbell biceps curl one-repetition maximum (1RM) test. On visits 2–3, participants performed 20 biceps curls at 50% of their 1RM, followed by their respective 10 min experimental manipulation (high vs. low cognitive exertion) and then a second set of biceps curls to exhaustion. Ratings of perceived exertion and electromyography of the biceps brachii, triceps brachii, upper trapezius, thoracic erector spinae and lumbar erector spinae were recorded during the physical task. The total number of repetitions completed was similar across the conditions. Results also failed to show between-condition differences for muscle activation and perceptions of exertion. Future research is needed to build an adequate knowledge base to determine whether there is an effect of mental fatigue on dynamic resistance-based task performance and, if so, identify the mechanisms explaining how and why.

The effects of whole-body vibration on upper- and lower-body EMG during static and dynamic contractions

2007 ◽  
Vol 32 (6) ◽  
pp. 1156-1163 ◽  
Author(s):  
Tom J. Hazell ◽  
Jennifer M. Jakobi ◽  
Kenji A. Kenno
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Biceps Brachii ◽  
Vastus Lateralis ◽  
Whole Body Vibration ◽  
Stimulus Frequency ◽  
Whole Body ◽  
Emg Activity ◽  
Lower Body ◽  
Body Vibration

Whole-body vibration (WBV) training uses a vertically oscillating platform and reports suggest that this perturbation elicits reflexive muscle contractions that augment muscle activity and contribute to increased strength. No WBV study has measured both upper- and lower-body muscle activation. The purpose of this study was to determine the optimal WBV stimulus (frequency × amplitude) to increase electromyography (EMG) in upper- and lower-body muscles for three distinctive unloaded actions: isometric semi-squat, dynamic leg squats, and static and dynamic bilateral bicep curls. Surface EMG was measured for the vastus lateralis (VL), biceps femoris (BF), biceps brachii (BB), and triceps brachii (TB) in 10 recreationally active male university students (24.4 ± 2.0 years; mean ± SD) when WBV was administered at 2 and 4 mm and at 25, 30, 35, 40, and 45 Hz. EMG changes are reported as the difference between WBV and no WBV EMG root mean square expressed as a percentage of maximum voluntary exertion (%MVE). In static semi-squat, WBV increased muscle activity 2.9%–6.7% in the VL and 0.8%–1.2% in the BF. During dynamic squatting, WBV increased muscle activity in the VL by 3.7%–8.7% and in the BF by 0.4%–2.0%. In a static biceps curl, WBV had no effect on BB EMG, but did increase TB activity 0.3%–0.7%. During dynamic biceps curls, WBV increased BB EMG activity by 0.6%–0.8% and TB activity by 0.2%–1.0%. The higher WBV amplitude (4 mm) and frequencies (35, 40, 45 Hz) resulted in the greatest increases in EMG activity.

scholarly journals Investigating the effects of mental fatigue on resistance exercise performance

2021 ◽  
Author(s):  
Denver M. Y. Brown ◽  
Amanda Farias Zuniga ◽  
Daanish Mulla ◽  
Divya Mendonca ◽  
Peter Keir ◽  
...  
Keyword(s):  
Muscle Activation ◽  
Perceived Exertion ◽  
Biceps Brachii ◽  
Experimental Manipulation ◽  
Mental Fatigue ◽  
Erector Spinae ◽  
Future Research ◽  
Dynamic Resistance ◽  
Triceps Brachii ◽  
Upper Trapezius

Mental fatigue can impart negative effects on subsequent physical performance, although the mechanisms underlying these effects are not well understood. This study examined whether mental fatigue confers negative carryover effects on the performance of a set of biceps curls, while also investigating physiological and psychological mechanisms proposed to explain the predicted effect. A randomized, cross-over design was employed. On Visit 1, participants (N = 10) performed a barbell biceps curl one-repetition maximum (1RM) test. On Visits 2/3, participants performed 20 biceps curls at 50% of their 1RM, followed by their respective 10-minute experimental manipulation (high vs. low cognitive exertion), and then a second set of biceps curls to exhaustion. Ratings of perceived exertion and electromyography of the biceps brachii, triceps brachii, upper trapezius, thoracic erector spinae, and lumbar erector spinae were recorded during the physical task. The total number of repetitions completed was similar across the conditions. Results also failed to show between-condition differences for muscle activation and perceptions of exertion. Future research is needed to build an adequate knowledge base to determine whether there is an effect of mental fatigue on dynamic resistance-based task performance, and if so, identifying the mechanisms explaining how and why.

scholarly journals LOCAL VIBRATION INFLUENCE OF ELECTROMYOGRAPHY PARAMETERS ON ANAEROBIC CAPACITY TEST IN ROWERS

2020 ◽  
Vol 6 ◽  
pp. 115
Author(s):  
Kalvis Ciekurs ◽  
Viesturs Krauksts ◽  
Daina Krauksta ◽  
Juris Grants ◽  
Žermēna Vazne
Keyword(s):  
Biceps Brachii ◽  
Vastus Lateralis ◽  
Anaerobic Capacity ◽  
Erector Spinae ◽  
Mathematical Statistics ◽  
Whole Body ◽  
Control Group ◽  
Triceps Brachii ◽  
Local Vibration ◽  
The Mean

Whole body vibration is a worldwide innovation as a part of training method that helps athletes to regain the power and get ready for next training faster. However less attention is paid to local vibration where an isolated muscle or muscle group is stimulated by the use of a vibration device. For the reason to determine the effect of local vibration on anaerobic capacity of rowers, two research groups were assembled from the students of Murjāņi Sport Gymnasium (MSG). The following methods were used in the study: tests – Concept-2, local vibration (LV) manipulations, electromyography and mathematical statistics. The electromyography was made with Biometric LTD. LV manipulations were done to the muscles erector spinae, latisimus dorsi, teres major, teres minor, trapezius, infraspinatus, deltoideus, slenius capitis, triceps brachii, gluteus maximus, semitendinosus, biceps femoris, semimembranosus, castrocnemius, tendo calcaneus, rectus femoris, vastus lateralis, tensor fascia latae, vastus medialis, sarterius, ligamentum patellae, tibialis anterior, rectus abdominis, pectoralis major un biceps brachii. We using 100 Hz frequency, 2 – 4 mm amplitude and different pressure on the muscles. The total LV application time was 5 to 20 min. The obtained data were processed using mathematical statistics. The results: having stated the result difference before LV and after it. The results testify significant improvement of Concept-2 tests results and electromyography results, what is showed by the difference of the mean results. Comparing the results of the rowers of experimental group (EG) and control group (CG) they have differences in the left side muscle latissimus dorsi after the t-test where p>0.05, but stating the percentage of the mean result difference of this muscle it was found out that p>0.05 what also shows significant changes in the muscle biopotential (mV). 

Sign in / Sign up

Export Citation Format

Share Document