scholarly journals Standing on elevated platform changes postural responses during arm movement

2020 ◽  
Author(s):  
Luis Mochizuki ◽  
Juliana Pennone ◽  
Aline Bigongiari ◽  
Renata Garrido Cosme ◽  
Monique Oliveira Baptista Cajueiro ◽  
...  
Keyword(s):  
Postural Control ◽  
Muscle Activity ◽  
Stable Condition ◽  
Arm Movement ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Surface Emg ◽  
Postural Adjustment ◽  
Postural Responses ◽  
Before And After

AbstractThis study investigated the muscle activity during the preparatory (anticipatory postural adjustment, APA), execution (online postural adjustments, OPA), and compensatory (compensatory postural adjustment, CPA) phases during standing with eyes opened or closed on an elevated platform. Eight healthy young women stood in the upright position, with eyes opened or closed, and did as-fast-as-they-could shoulder flexions on the ground and on 1-m-height-portable-elevated-platform. The surface EMG of trunk (lumbar extensor, and rectus abdominis) and lower limb (rectus femoris, biceps femoris, tibialis anterior and gastrocnemius lateralis) muscles during this task were recorded (1 kHz sampling frequency) and compared during these three phases. Analysis of variance was applied to compare the effects of height (floor and elevated platform), vision (open and closed), and postural adjustment (APA, OPA and CPA) into the activity of each muscle. These muscles were more active during OPA (p<0.0001) and less active during APA. On the elevated platform, these postural muscles presented more activty during APA (p<0.001). During the most stable condition (on the ground with eyes opened), muscle activity during APA and OPA was negatively correlated, and not correlated between OPA and CPA. Our results suggest postural control adapts to sensory, motor, and cognitive conditions. Therefore, the increased demand for postural control, generated due to the height of the support base, provokes the need for greater flexibility of postural synergies and causes a change in muscle activity.Summary StatementWe discuss how postural muscle activity behaves before and after a fast upper arms movement when someone stands on a elevated platform or on the ground.

scholarly journals Leg Muscle Activity and Perception of Effort before and after Four Short Sessions of Submaximal Eccentric Cycling

2020 ◽  
Vol 17 (21) ◽  
pp. 7702
Author(s):  
Pierre Clos ◽  
Romuald Lepers
Keyword(s):  
Muscle Activity ◽  
Peak Power ◽  
Vastus Lateralis ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Peak Power Output ◽  
Leg Muscles ◽  
Perception Of Effort ◽  
Before And After ◽  
Power Outputs

Background: This study tested muscle activity (EMG) and perception of effort in eccentric (ECC) and concentric (CON) cycling before and after four sessions of both. Methods: Twelve volunteers naïve to ECC cycling attended the laboratory six times. On day 1, they performed a CON cycling peak power output (PPO) test. They then carried-out four sessions comprising two sets of 1 to 1.5-min cycling bouts at 5 intensities (30, 45, 60, 75, and 90% PPO) in ECC and CON cycling. On day 2 and day 6 (two weeks apart), EMG root mean square of the vastus lateralis (VL), rectus femoris (RF), biceps femoris (BF), and soleus (SOL) muscles, was averaged from 15 to 30 s within each 1-min bout and perception of effort was asked after 45 s. Results: Before the four cycling sessions, while VL EMG was lower in ECC than CON cycling, most variables were not different. Afterwards, ECC cycling exhibited lower RF EMG at 75 and 90% PPO (all p < 0.02), lower VL and BF EMG at all exercise intensities (all p < 0.02), and inferior SOL EMG (all p < 0.04) except at 45% PPO (p = 0.07). Perception of effort was lower in ECC cycling at all exercise intensities (all p < 0.03) but 60% PPO (p = 0.11). Conclusions: After four short sessions of ECC cycling, the activity of four leg muscles and perception of effort became lower in ECC than in CON cycling at most of five power outputs, while they were similar before.

scholarly journals Investigation of lower limb’s muscles activity during performance of salat between two age groups

2019 ◽  
Vol 14 (2) ◽  
pp. 608
Author(s):  
N. Abdul Malik ◽  
Z. Wahid ◽  
A. F. Zulkipili ◽  
S. Noorjannah Ibrahim ◽  
T. S. Gunawan ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Age Groups ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Surface Emg ◽  
Active Muscle ◽  
Factors Affecting ◽  
Significant Difference ◽  
Result Show ◽  
Two Age Groups

Muscles play an important role in the movement of limbs. They undergo contraction to straighten or to bend a joint for the limbs to move. There are many factors that can affect muscle activity. Age could be one of the possible factors affecting muscle activity. The purpose of this study was to investigate the lower limb’s muscles activity during performance of <em>salat</em> between two age groups. The lower limb’s muscles investigated were Gastrocnemius (GAS), Biceps Femoris (BF), Tibialis Anterior (TA) and Rectus Femoris (RF). The postures involve are standing, bowing, prostrating and sitting. The electromyography (EMG) signals of the muscles were measured using the technique of surface EMG (sEMG). The signals were acquired by using Delsys Bagnoli™ Desktop sEMG system and EMGworks®. Ten healthy subjects from two age groups were recruited in this study. The first group consists of five males aged between 20 to 29 while the second group consists of five males aged above 40. The raw EMG signals acquired were analyzed and the EMG envelopes were developed using MATLAB. The averaged RMS values of EMG for each muscle were also calculated. Analysis of variance (ANOVA) of the EMGs was obtained by using <em>F</em>-test. Further investigation of the variance was performed by using Tukey comparison. From the results, the most active muscle during the performance of <em>salat</em> is BF while the less active muscle is GAS for both age groups. The statistical result show that there is no difference in the muscle activity pattern between the two age groups but there is significant difference among the muscles investigated.

scholarly journals Relationship between Muscular Activity and Postural Control Changes after Proprioceptive Focal Stimulation (Equistasi®) in Middle-Moderate Parkinson’s Disease Patients: An Explorative Study

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 560
Author(s):  
Fabiola Spolaor ◽  
Marco Romanato ◽  
Guiotto Annamaria ◽  
Antonella Peppe ◽  
Leila Bakdounes ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Postural Control ◽  
Quantitative Estimation ◽  
Force Plate ◽  
Muscular Activity ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Eyes Open ◽  
Romberg Test

The aim of this study was to investigate the effects of Equistasi®, a wearable device, on the relationship between muscular activity and postural control changes in a sample of 25 Parkinson’s disease (PD) subjects. Gait analysis was carried out through a six-cameras stereophotogrammetric system synchronized with two force plates, an eight-channel surface electromyographic system, recording the activity of four muscles bilaterally: Rectus femoris, tibialis anterior (TA), biceps femoris, and gastrocnemius lateralis (GL). The peak of the envelope (PoE) and its occurrence within the gait cycle (position of the peak of the envelope, PPoE) were calculated. Frequency-domain posturographic parameters were extracted while standing still on a force plate in eyes open and closed conditions for 60 s. After the treatment with Equistasi®, the mid-low (0.5–0.75) Hz and mid-high (0.75–1 Hz) components associated with the vestibular and somatosensory systems, PoE and PPoE, displayed a shift toward the values registered on the controls. Furthermore, a correlation was found between changes in proprioception (power spectrum frequencies during the Romberg Test) and the activity of GL, BF (PoE), and TA (PPoE). Results of this study could provide a quantitative estimation of the effects of a neurorehabilitation device on the peripheral and central nervous system in PD.

Lower-Extremity Muscle Activity During Aquatic and Land Treadmill Running at the Same Speeds

2014 ◽  
Vol 23 (2) ◽  
pp. 107-122 ◽  
Author(s):  
W. Matthew Silvers ◽  
Eadric Bressel ◽  
D. Clark Dickin ◽  
Garry Killgore ◽  
Dennis G. Dolny
Keyword(s):  
Lower Extremity ◽  
Outcome Measures ◽  
Muscle Activity ◽  
Tibialis Anterior ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Swing Phase ◽  
Treadmill Running ◽  
Vastus Medialis ◽  
Lower Extremity Muscle

Context:Muscle activation during aquatic treadmill (ATM) running has not been examined, despite similar investigations for other modes of aquatic locomotion and increased interest in ATM running.Objectives:The objectives of this study were to compare normalized (percentage of maximal voluntary contraction; %MVC), absolute duration (aDUR), and total (tACT) lower-extremity muscle activity during land treadmill (TM) and ATM running at the same speeds.Design:Exploratory, quasi-experimental, crossover design.Setting:Athletic training facility.Participants:12 healthy recreational runners (age = 25.8 ± 5 y, height = 178.4 ± 8.2 cm, mass = 71.5 ± 11.5 kg, running experience = 8.2 ± 5.3 y) volunteered for participation.Intervention:All participants performed TM and ATM running at 174.4, 201.2, and 228.0 m/min while surface electromyographic data were collected from the vastus medialis, rectus femoris, gastrocnemius, tibialis anterior, and biceps femoris.Main Outcome Measures:For each muscle, a 2 × 3 repeated-measures ANOVA was used to analyze the main effects and environment–speed interaction (P ≤ .05) of each dependent variable: %MVC, aDUR, and tACT.Results:Compared with TM, ATM elicited significantly reduced %MVC (−44.0%) but increased aDUR (+213.1%) and tACT (+41.9%) in the vastus medialis, increased %MVC (+48.7%) and aDUR (+128.1%) in the rectus femoris during swing phase, reduced %MVC (−26.9%) and tACT (−40.1%) in the gastrocnemius, increased aDUR (+33.1%) and tACT (+35.7%) in the tibialis anterior, and increased aDUR (+41.3%) and tACT (+29.2%) in the biceps femoris. At faster running speeds, there were significant increases in tibialis anterior %MVC (+8.6−15.2%) and tACT (+12.7−17.0%) and rectus femoris %MVC (12.1−26.6%; swing phase).Conclusion:No significant environment–speed interaction effects suggested that observed muscle-activity differences between ATM and TM were due to environmental variation, ie, buoyancy (presumed to decrease %MVC) and drag forces (presumed to increase aDUR and tACT) in the water.

scholarly journals Kinematic and EMG Comparison Between Variations of Unilateral Squats Under Different Stabilities

2020 ◽  
Vol 4 (02) ◽  
pp. E59-E66
Author(s):  
Roland van den Tillaar ◽  
Stian Larsen
Keyword(s):  
Muscle Activity ◽  
Rectus Femoris ◽  
Gluteus Medius ◽  
Biceps Femoris ◽  
Peak Force ◽  
Erector Spinae ◽  
Trunk Muscles ◽  
Training Experience ◽  
Free Weight ◽  
Weight Condition

AbstractThe purpose of the study was to compare kinematics and muscle activity between two variations of unilateral squats under different stability conditions. Twelve male volunteers (age: 23±5 years, mass: 80±17 kg, height: 1.81±0.11 m, strength-training experience: 4.3±1.9 years) performed four repetitions with the same external load (≈4RM). Two variations (with the non-stance leg forwards vs. backwards) were performed in a Smith-machine and free-weight condition. The variables were barbell velocity, lifting time and surface electromyography activity of the lower extremity and trunk muscles during the descending and ascending phase. The main findings were 1) peak force was higher when performing the unilateral squats in the Smith machine; 2) peak ascending barbell velocity increased from repetition 3–4 with free weight; and 3) muscle activity from the rectus femoris, vastus lateral, biceps femoris, gluteus medius, and erector spinae increased with repetitions, whereas gluteus, and medial vastus and shank muscles were affected by the conditions. It was concluded that more peak force could be produced because of increased stability. However, peak barbell velocity increased from repetition to repetition in free-weight unilateral squats, which was probably because the participants grew more comfortable. Furthermore, increased instability causes more gluteus and vastus medial activation and foot variations mainly affected the calf muscles.

scholarly journals Age-specific modulation of intermuscular beta coherence during gait before and after experimentally induced fatigue

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Paulo Cezar Rocha dos Santos ◽  
Claudine J. C. Lamoth ◽  
Fabio Augusto Barbieri ◽  
Inge Zijdewind ◽  
Lilian Teresa Bucken Gobbi ◽  
...  
Keyword(s):  
Vastus Lateralis ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Treadmill Walking ◽  
Beta Band ◽  
Sit To Stand ◽  
Corticospinal Tracts ◽  
Before And After ◽  
Oscillatory Coupling ◽  
Experimentally Induced

Abstract We examined the effects of age on intermuscular beta-band (15–35 Hz) coherence during treadmill walking before and after experimentally induced fatigue. Older (n = 12) and younger (n = 12) adults walked on a treadmill at 1.2 m/s for 3 min before and after repetitive sit-to-stand, rSTS, to induce muscle fatigability. We measured stride outcomes and coherence from 100 steps in the dominant leg for the synergistic (biceps femoris (BF)-semitendinosus, rectus femoris (RF)-vastus lateralis (VL), gastrocnemius lateralis (GL)-Soleus (SL), tibialis anterior (TA)-peroneus longus (PL)) and for the antagonistic (RF-BF and TA-GL) muscle pairs at late swing and early stance. Older vs. younger adults had 43–62% lower GL-SL, RF-VL coherence in swing and TA-PL and RF-VL coherence in stance. After rSTS, RF-BF coherence in late swing decreased by ~ 20% and TA-PL increased by 16% independent of age (p = 0.02). Also, GL-SL coherence decreased by ~ 23% and increased by ~ 23% in younger and older, respectively. Age affects the oscillatory coupling between synergistic muscle pairs, delivered presumably via corticospinal tracts, during treadmill walking. Muscle fatigability elicits age-specific changes in the common fluctuations in muscle activity, which could be interpreted as a compensation for muscle fatigability to maintain gait performance.

Is Tensiomyography-Derived Velocity of Contraction a Sensitive Marker to Detect Acute Performance Changes in Elite Team-Sport Athletes?

2020 ◽  
Vol 15 (1) ◽  
pp. 31-37
Author(s):  
Lucas A. Pereira ◽  
Rodrigo Ramirez-Campillo ◽  
Saul Martín-Rodríguez ◽  
Ronaldo Kobal ◽  
César C.C. Abad ◽  
...  
Keyword(s):  
Training Session ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Team Sport ◽  
Technical Training ◽  
Effect Sizes ◽  
Squat Jump ◽  
National Team ◽  
Before And After ◽  
Sensitive Marker

Purpose: To examine the variations in the velocity of contraction (Vc) assessed using tensiomyography, vertical jumping ability, and sprinting speed induced by 4 different exercise protocols (ie, strength, sprint, plyometric, and technical training sessions) in 14 male national-team rugby players (age 21.8 [2.6] y, weight 83.6 [8.5] kg, and height 177.4 [6.7] cm). Methods: Physical tests were conducted immediately before and after 4 distinct workouts in the following order: tensiomyography in the rectus femoris and biceps femoris muscles, squat and countermovement jumps, and 30-m sprint velocity. To analyze the differences in the assessed variables before and after each training session, the differences based on magnitudes were calculated. Results: After strength and plyometric workouts, the players presented possible to almost certain impairments in sprint and jump performance and in the Vc of the rectus femoris (effect sizes 0.26–0.64). After the sprint-training session, possible to very likely decreases were observed in the squat jump, 30-m sprint, and Vc of the biceps femoris (effect sizes 0.21–0.44). By contrast, after the technical training, athletes demonstrated a possible increase in the squat jump and Vc in both muscles examined (effect sizes 0.13–0.20). Conclusions: The main finding of this research is that, for the vast majority of results, the direction of changes observed in Vc were the same as those observed in performance assessments. This suggests that Vc might be used as a sensitive marker of acute variations in speed and power performance of elite team-sport athletes.

The frequency of alternate muscle activity is associated with the attenuation in muscle fatigue

2006 ◽  
Vol 101 (3) ◽  
pp. 715-720 ◽  
Author(s):  
Motoki Kouzaki ◽  
Minoru Shinohara
Keyword(s):  
Muscle Fatigue ◽  
Muscle Activity ◽  
Healthy Subjects ◽  
Vastus Lateralis ◽  
Rectus Femoris ◽  
Knee Extension ◽  
Voluntary Contraction ◽  
Sustained Contraction ◽  
Low Level ◽  
Before And After

Alternate muscle activity between synergist muscles has been demonstrated during low-level sustained contractions [≤5% of maximal voluntary contraction (MVC) force]. To determine the functional significance of the alternate muscle activity, the association between the frequency of alternate muscle activity during a low-level sustained knee extension and the reduction in knee extension MVC force was studied. Forty-one healthy subjects performed a sustained knee extension at 2.5% MVC force for 1 h. Before and after the sustained knee extension, MVC force was measured. The surface electromyogram was recorded from the rectus femoris (RF), vastus lateralis (VL), and vastus medialis (VM) muscles. The frequency of alternate muscle activity for RF-VL, RF-VM, and VL-VM pairs was determined during the sustained contraction. The frequency of alternate muscle activity ranged from 4 to 11 times/h for RF-VL (7.0 ± 2.0 times/h) and RF-VM (7.0 ± 1.9 times/h) pairs, but it was only 0 to 2 times/h for the VL-VM pair (0.5 ± 0.7 times/h). MVC force after the sustained contraction decreased by 14% ( P < 0.01) from 573.6 ± 145.2 N to 483.3 ± 130.5 N. The amount of reduction in MVC force was negatively correlated with the frequency of alternate muscle activity for the RF-VL and RF-VM pairs ( P < 0.001 and r = 0.65 for both) but not for the VL-VM pair. The results demonstrate that subjects with more frequent alternate muscle activity experience less muscle fatigue. We conclude that the alternate muscle activity between synergist muscles attenuates muscle fatigue.

Proprioceptive Neuromuscular Facilitation Decreases Muscle Activity during the Stretch Reflex in Selected Posterior Thigh Muscles

2000 ◽  
Vol 9 (4) ◽  
pp. 269-278 ◽  
Author(s):  
Allyson M. Carter ◽  
Stephen J. Kinzey ◽  
Linda F. Chitwood ◽  
Judith L Cole
Keyword(s):  
Outcome Measures ◽  
Muscle Activity ◽  
Biceps Femoris ◽  
Tendon Injury ◽  
Hamstring Muscle ◽  
Muscle Response ◽  
Proprioceptive Neuromuscular Facilitation ◽  
Before And After ◽  
Increase Risk ◽  
Length Changes

Context:Proprioceptive neuromuscular facilitation (PNF) is commonly used before competition to increase range of motion. It is not known how it changes muscle response to rapid length changes.Objective:To determine whether PNF alters hamstring muscle activity during response to rapid elongation.Design:2 X 2 factorial.Setting:Laboratory.Participants:Twenty-four women; means: 167.27 cm, 58.92 kg, 21.42 y, 18.41% body fat, 21.06 kg/m2BMI.intervention:Measurements before and after either rest or PNF were compared.Main Outcome Measures:Average muscle activity immediately after a rapid and unexpected stretch, 3 times pretreatment and posttreatment, averaged into 2 pre-and post- measures.Results:PNF caused decreased activity in the biceps femoris during response to a sudden stretch (P= .04). No differences were found in semitendinosus activity (P= .35).Conclusions:Decreased muscle activity likely results from acute desensitization of the muscle spindle, which might increase risk of muscle and tendon injury.

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