scholarly journals The bilateral limb deficit (BLD) phenomenon during leg press: a preliminary investigation into central and peripheral factors

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Emily Whitcomb ◽  
Oscar Ortiz ◽  
Jacqueline Toner ◽  
Usha Kuruganti
Keyword(s):  
Muscle Activation ◽  
Brain Activity ◽  
Vastus Lateralis ◽  
Preliminary Investigation ◽  
Rectus Femoris ◽  
Surface Emg ◽  
Leg Press ◽  
Bilateral Limb Deficit ◽  
Significant Difference ◽  
The Right

Abstract Background The bilateral limb deficit (BLD) phenomenon suggests that lower forces are produced with bilateral limb contractions compared to the summed force produced when the same muscles are contracted unilaterally. While interhemispheric inhibition has been suggested as a cause of BLD, the origin of the deficit is yet to be determined. The aim of this study was to investigate central and peripheral factors responsible for the BLD during leg press using surface electromyography (EMG) and electroencephalography (EEG). Methods Fourteen adults (age = 23.7 ± 4.7 years old) completed bilateral (BL), unilateral left (UL) and unilateral right (UR) isometric leg press exercises. Bilateral limb ratio (BLR) was calculated similar to previous studies and surface EMG from three muscles of the quadriceps femoris (vastus lateralis, vastus medialis and rectus femoris) was used to measure the level of muscle activation. Movement related cortical potentials (MRCPs) over the left and right motor cortex areas (C3 and C4, respectively) were used to assess brain activity asymmetries reflecting central factors. Results No significant difference was noted in the mean BLR (BLR = 94.8%), but a subset of ten participants did demonstrate a BLD (BLR = 81.4%, p < 0.01). Mean differences in relative activation were found among the three quadricep muscles (p < 0.001) with the right VM having significantly higher amplitude for the unilateral right (0.347 ± 0.318 mV) and bilateral right (0.436 ± 0.470 mV) conditions, respectively) than either the VL or RF (p < 0.05). The VL had significantly lower amplitudes in all conditions (0.127 ± 0.138 mV; 0.111 ± 0.104 mV; 0.120 ± 0.105 mV; 0.162 ± 0.147 mV for unilateral left, bilateral left, unilateral right, and bilateral right, respectively). However no overall significant differences were noted between bilateral and unilateral conditions. No significant differences in MRCPs were observed between brain activity of the C3 and C4 electrodes in any of the conditions. Conclusion While the sample size was low, this exploratory study noted the presence of BLD however the results did not provide evidence of significant limitations in either the EMG or EEG data.

scholarly journals The Bilateral Limb Deficit (BLD) Phenomenon During Leg Press: An Investigation Into Central And Peripheral Factors

2020 ◽  
Author(s):  
Emily Whitcomb ◽  
Oscar Ortiz ◽  
Jacqueline Toner ◽  
Usha Kuruganti
Keyword(s):  
Brain Activity ◽  
Vastus Lateralis ◽  
Rectus Femoris ◽  
Signal Amplitude ◽  
Surface Emg ◽  
Leg Press ◽  
Bilateral Limb Deficit ◽  
Eeg Data ◽  
Generating Capacity ◽  
The Difference

Abstract Background: The bilateral limb deficit (BLD) phenomenon is the difference in maximal or near maximal force generating capacity of muscles when they are contracted alone or in combination with the contralateral muscles. It has been suggested that the BLD may be due to interhemispheric inhibition, however the origin of the deficit is yet to be determined. The aim of this study was to investigate central and peripheral factors responsible for the BLD during leg press using surface electromyography (EMG) and electroencephalography (EEG). Methods: Fourteen adults (age = 23.7 ± 4.7 years old) completed bilateral (BL), unilateral left (UL) and unilateral right (UR) isometric leg press exercises. Bilateral limb ratio (BLR) was calculated similar to previous studies and surface EMG from three muscles of the quadriceps femoris (vastus lateralis, vastus medialis and rectus femoris) were used to compare signal amplitude in each condition. Movement related cortical potentials (MRCPs) over the left and right motor cortex areas (C3 and C4, respectively) were used to assess brain activity asymmetries reflecting central factors. Results: The BLD was present in ten of the fourteen participants (mean BLR=81.4%). Mean RMS activity demonstrated differences in amplitudes between the quadriceps muscles, however no significant differences were noted between bilateral and unilateral conditions. No significant differences in MRCPs were observed between brain activity of the C3 and C4 electrodes in any of the conditions. Conclusion: This study noted the presence of BLD however the results did not provide evidence of significant limitations in either the EMG and EEG data.

scholarly journals The Electromyographic Threshold in Girls and Women

2017 ◽  
Vol 29 (1) ◽  
pp. 84-93 ◽  
Author(s):  
Devon Long ◽  
Raffy Dotan ◽  
Brynlynn Pitt ◽  
Brandon McKinlay ◽  
Thomas D. O’Brien ◽  
...  
Keyword(s):  
Muscle Activation ◽  
Vastus Lateralis ◽  
Regression Line ◽  
Surface Emg ◽  
Cycle Ergometry ◽  
High Threshold ◽  
Type Ii ◽  
Progressive Exercise ◽  
Muscular Function ◽  
The Right

Background:The electromyographic threshold (EMGTh) is thought to reflect increased high-threshold/type-II motor-unit (MU) recruitment and was shown higher in boys than in men. Women differ from men in muscular function.Purpose:Establish whether females’ EMGTh and girls–women differences are different than males’.Methods:Nineteen women (22.9 ± 3.3yrs) and 20 girls (10.3 ± 1.1yrs) had surface EMG recorded from the right and left vastus lateralis muscles during ramped cycle-ergometry to exhaustion. EMG root-mean-squares were averaged per pedal revolution. EMGTh was determined as the least residual sum of squares for any two regression-line data divisions, if the trace rose ≥ 3SD above its regression line. EMGTh was expressed as % final power-output (%Pmax) and %VO2pk power (%PVO2pk).Results:EMGTh was detected in 13 (68%) of women, but only 9 (45%) of girls (p < .005) and tended to be higher in the girls (%Pmax= 88.6 ± 7.0 vs. 83.0 ± 6.9%, p = .080; %PVO2pk= (101.6 ± 17.6 vs. 90.6 ± 7.8%, p = .063). When EMGTh was undetected it was assumed to occur at 100%Pmax or beyond. Consequently, EMGTh values turned significantly higher in girls than in women (94.8 ± 7.4 vs. 88.4 ± 9.9%Pmax, p = .026; and 103.2 ± 11.7 vs. 95.2 ± 9.9%PVO2pk, p = .028).Conclusions:During progressive exercise, girls appear to rely less on higher-threshold/type-II MUs than do women, suggesting differential muscle activation strategy.

scholarly journals Evaluation of the Lower Limb Muscles’ Electromyographic Activity during the Leg Press Exercise and Its Variants: A Systematic Review

2020 ◽  
Vol 17 (13) ◽  
pp. 4626
Author(s):  
Isabel Martín-Fuentes ◽  
José M. Oliva-Lozano ◽  
José M. Muyor
Keyword(s):  
Muscle Activation ◽  
Vastus Lateralis ◽  
Muscular Activity ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Quadriceps Muscle ◽  
Electromyographic Activity ◽  
Full Extension ◽  
Cross Sectional ◽  
Leg Press

The aim of this study was to analyze the literature on muscle activation measured by surface electromyography (sEMG) of the muscles recruited when performing the leg press exercise and its variants. The Preferred Reporting Items of Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed to report this review. The search was carried out using the PubMed, Scopus, and Web of Science electronic databases. The articles selected met the following inclusion criteria: (a) a cross-sectional or longitudinal study design; (b) neuromuscular activation assessed during the leg press exercise, or its variants; (c) muscle activation data collected using sEMG; and (d) study samples comprising healthy and trained participants. The main findings indicate that the leg press exercise elicited the greatest sEMG activity from the quadriceps muscle complex, which was shown to be greater as the knee flexion angle increased. In conclusion, (1) the vastus lateralis and vastus medialis elicited the greatest muscle activation during the leg press exercise, followed closely by the rectus femoris; (2) the biceps femoris and the gastrocnemius medialis showed greater muscular activity as the knee reached full extension, whereas the vastus lateralis and medialis, the rectus femoris, and the tibialis anterior showed a decreasing muscular activity pattern as the knee reached full extension; (3) evidence on the influence of kinematics modifications over sEMG during leg press variants is still not compelling as very few studies match their findings.

The Effect of Patellar Taping on Quadriceps Activity Onset in the Absence of Pain

1999 ◽  
Vol 15 (4) ◽  
pp. 373-380 ◽  
Author(s):  
David Parsons ◽  
Wendy Gilleard
Keyword(s):  
Muscle Activation ◽  
Vastus Lateralis ◽  
Motor Units ◽  
Surface Emg ◽  
Mechanical Effect ◽  
Stair Ascent ◽  
Patella Position ◽  
The Right ◽  
Asymptomatic Subjects ◽  
Taping Technique

Patellofemoral taping is a technique used in the management of patellofemoral pain that has been shown to alter the pattern of muscle activation onset in symptomatic subjects. It is unknown, however, if this taping technique directly influences the patterns of muscle activity that controls patella position or if its benefits are more related to the effect of pain reduction. The purpose of this study was to investigate the effect of a taping technique on the muscle activation onset of selected quadriceps muscles where pain was not a confounding factor. Thirteen asymptomatic subjects completed a stair ascent and descent task with the right patella untaped and taped for a medial patella glide. Muscle activation onset was determined by computer algorithm from surface EMG of vastus lateralis (VL) and vastus medialis obliquus (VMO). Taping significantly delayed the muscle activation onset of VMO and VL during stair ascent. There was no significant change for stair descent. This effect may be an attempt by the motor control system to counter the mechanical effect of patella perturbation or may be due to cutaneous stimulation affecting threshold or recruitment of motor units.

scholarly journals Muscle Activation and Kinematic Analysis during the Inclined Leg Press Exercise in Young Females

2020 ◽  
Vol 17 (22) ◽  
pp. 8698
Author(s):  
Isabel Martín-Fuentes ◽  
José M. Oliva-Lozano ◽  
José M. Muyor
Keyword(s):  
Muscle Activation ◽  
External Rotation ◽  
Vastus Lateralis ◽  
Maximum Velocity ◽  
Rectus Femoris ◽  
Thigh Muscle ◽  
Vastus Medialis ◽  
Cross Sectional ◽  
Female Population ◽  
Leg Press

Knee joint muscle activation imbalances, especially weakness in the vastus medialis oblique, are related to patellofemoral pain within the female population. The available literature presents the leg press as an exercise which potentially targets vastus medialis oblique activation, thus reducing imbalances in the quadriceps muscles. The main aim of the present study was to compare thigh muscle activation and kinematic parameters under different conditions during the inclined leg press exercise in a young female population. A cross-sectional study was conducted on 10 young, trained females. Muscle activation of the vastus medialis oblique, vastus lateralis, rectus femoris and gluteus medialis was analyzed under five different inclined leg press conditions, modifying the feet rotation (0–45° external rotation) and the stance width (100–150% hip width) on the footplate. All the conditions were performed at two different movement velocities: controlled velocity (2″ eccentric–2″ concentric) and maximal intended velocity. Mean propulsive velocity, maximum velocity and maximum power were also assessed. The results show that both controlled velocity conditions and maximal intended velocity conditions elicited a similar muscle activation pattern with greater activation during the concentric phase (p < 0.001, ηp2 = 0.96). The maximal intended velocity conditions showed greater overall muscle activation (p < 0.001, ηp2 = 0.91). The vastus medialis oblique presented the greatest muscle activation, followed by the rectus femoris, vastus lateralis and, the gluteus medialis. Furthermore, the inclined leg press condition with 0º feet rotation, 100% hip width distance and the maximal intended velocity generated the greatest kinematic parameter outputs. In conclusion, the inclined leg press exercise might be an optimal exercise to target vastus medialis activation regardless of the feet rotation and stance width conditions.

Intent-Related Differences in Surface EMG of Maximum Eccentric and Concentric Contractions

2003 ◽  
Vol 19 (2) ◽  
pp. 99-105 ◽  
Author(s):  
Mark D. Grabiner ◽  
Tammy M. Owings
Keyword(s):  
Muscle Activation ◽  
Vastus Lateralis ◽  
Knee Extensor ◽  
Eccentric Contraction ◽  
Surface Emg ◽  
Vastus Lateralis Muscle ◽  
Concentric Contractions ◽  
Concentric Contraction ◽  
Contraction Condition ◽  
The Difference

For this study it was hypothesized that when participants intended to perform a maximum voluntary concentric (or eccentric) contraction but had an eccentric (or concentric) contraction imposed upon them, the initial EMG measured during the isometric phase preceding the onset of the dynamometer motion would reflect the intended contraction condition. The surface EMG of the vastus lateralis muscle was measured in 24 participants performing isokinetic concentric and eccentric maximum voluntary knee extensor contractions. The contractions were initiated from rest and from the same knee flexion angle and required the same level of external force to trigger the onset of dynamometer motion. Vastus lateralis EMG were quantified during the isometric phase preceding the onset of the dynamometer motion. When participants intended to perform a concentric contraction but had an eccentric contraction imposed upon them, the initial EMG resembled that of a concentric contraction. When they intended to perform an eccentric contraction but had a concentric contraction imposed upon them, the initial EMG resembled that of an eccentric contraction. Overall, the difference between concentric and eccentric contractions observed during the period of theinitialmuscle activation implies that descending signals include information that distinguishes between eccentric and concentric contractions.

scholarly journals A Comparison of the Transient Effect of Complex and Core Stability Exercises on Static Balance Ability and Muscle Activation during Static Standing in Healthy Male Adults

Healthcare ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 375
Author(s):  
Ho-Jin Shin ◽  
Jin-Hwa Jung ◽  
Sung-Hyeon Kim ◽  
Suk-Chan Hahm ◽  
Hwi-young Cho
Keyword(s):  
Path Length ◽  
Muscle Activation ◽  
Exercise Program ◽  
Rectus Femoris ◽  
Core Stability ◽  
Static Balance ◽  
Healthy Male ◽  
Lower Extremity Muscle ◽  
Significant Difference ◽  
Balance Ability

Balance ability is a necessary exercise factor required for the activities of daily living. This study investigated the effects of short-term complex exercise (CE) and core stability exercise (CSE) on balance ability and trunk and lower-extremity muscle activation on healthy male adults. Twenty-nine healthy male adults were included. All performed CE and CSE for 1 min each; the exercise order was randomized. The primary and secondary outcomes were balance ability and muscle activation, respectively. In balance ability, CE showed a significant difference in all variables in both eye-opened and eye-closed conditions compared with the baseline (p < 0.05). In comparisons among exercises, the path length and average velocity variables showed a significant decrease in the eye-opened condition, and the path length variable showed a significant decrease in the eye-closed condition (p < 0.05). In muscle activation, CE showed a significant increase in the gluteus medius (Gmed) and decrease in the rectus femoris (RF), tibialis anterior (TA), and RF/biceps femoris (BF) ratio in the eye-opened condition compared to the baseline and a significant decrease in RF and RF/BF ratio in the eye-closed condition (p < 0.05). Both CE and CSE improved the static balance ability. Furthermore, muscle activation significantly increases in Gmed and decreases in the RF, TA, and RF/BF ratio. Therefore, we recommend including CE in an exercise program that has the purpose of improving static balance ability.

scholarly journals Acute effect of partial body weight suspension on the level of cocontraction and gait biomechanics in women with knee osteoarthritis

2020 ◽  
Vol 33 ◽  
Author(s):  
Deborah Hebling Spinoso ◽  
Marcus Vinicius de Sobral Carvalho ◽  
Ana Carolina de Souza Trentin ◽  
Marcelo Tavella Navega
Keyword(s):  
Body Weight ◽  
Knee Osteoarthritis ◽  
Vastus Lateralis ◽  
Functional Limitation ◽  
Gluteus Maximus ◽  
Rectus Femoris ◽  
Treadmill Running ◽  
Significance Level ◽  
Significant Difference ◽  
Partial Body

Abstract Introduction: Knee osteoarthritis (OAK) is one of the most prevalent rheumatic diseases in the population, characterized by functional limitation and gait difficulties with profound clinical relevance, as walking is the most frequently performed daily activity. These functional limitations may be more pronounced when the disease is associated with obesity. Objective: To investigate the effect of different body weight suspension percentages on gait biomechanical variables and co-contraction percentages in women with OAK. Method: Fourteen women aged 50-75 years, with a body mass index between 26 and 35 and radiological diagnosis of OAK participated in the study. On the first day, anamnesis and familiarization with gait on the treadmill was performed. On the second day, treadmill gait assessment was performed using partial body weight support (SPPC) in three conditions-15%, 30%, and 45% suspension. During the evaluation, electromyographic and kinematic data were collected. The variables analyzed were percentage of hip (gluteus maximus/rectus femoris), knee (femoral biceps/vastus lateralis), and ankle (anterior tibial/lateral gastrocnemius), and length and step widths. A one-way analysis of variance was conducted, with a significance level of p < 0.05. Results: There was no significant difference in the length and step width and the level of co-contraction between the running conditions analyzed. Conclusion: Body weight suspension using SPPC during treadmill running did not alter the biomechanical variables of the gait of women with OAK.

scholarly journals Quadriceps and hamstrings coactivation in exercises used in prevention and rehabilitation of hamstring strain injury in young soccer players

2019 ◽  
Author(s):  
Gonzalo Torres ◽  
David Chorro ◽  
Archit Navandar ◽  
Javier Rueda ◽  
Luís Fernández ◽  
...  
Keyword(s):  
Muscle Activation ◽  
Vastus Lateralis ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Activation Pattern ◽  
Male Youth ◽  
Maximum Voluntary Isometric Contraction ◽  
Hamstring Strain ◽  
Exercise Muscle ◽  
Injury Recovery

AbstractThis study aimed to study the co-activation of hamstring-quadriceps muscles during submaximal strength exercises without the use of maximum voluntary isometric contraction testing and compare (i) the inter-limb differences in muscle activation, (ii) the intra-muscular group activation pattern, and (iii) the activation during different phases of the exercise. Muscle activation was recorded by surface electromyography of 19 elite male youth players. Participants performed five repetitions of the Bulgarian squat, lunge and the squat with an external load of 10 kg. Electrical activity was recorded for the rectus femoris, vastus medialis, vastus lateralis, biceps femoris and semitendinosus. No significant inter-limb differences were found (F1, 13=619; p=0.82; partial η2=0.045). Significant differences were found in the muscle activation between different muscles within the muscle group (quadriceps and hamstrings) for each of the exercises: Bulgarian squat (F1,18=331: p<0.001; partial η2=0.80), lunge (F4,72=114.5; p<0.001; partial η2=0.86) and squat (F1,16=247.31; p<0.001; partial η2=0.93).Differences were found between the concentric, isometric and eccentric phases of each of the exercises (F2, 26=52.27; p=0.02; partial η2=0.80). The existence of an activation pattern of each of the muscles in the three proposed exercises could be used for muscle assessment and as a tool for injury recovery.

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