scholarly journals Comparison of thigh muscle activations in single leg exercises: bench squat, step-up, airborne lunge

2021 ◽  
Vol 25 (6) ◽  
pp. 342-348
Author(s):  
Fahri S. Çinarli ◽  
Sena Çinarli ◽  
Emin Kafkas
Keyword(s):  
Muscle Activation ◽  
Vastus Lateralis ◽  
Biceps Femoris ◽  
Thigh Muscle ◽  
Knee Extensors ◽  
Energy Costs ◽  
Co Activation ◽  
Significant Difference ◽  
Muscle Activations ◽  
Sports Sciences

Background and Study Aim. Single leg exercises have some advantages in terms of time, practice and energy costs. However, the activation values that occur in different single leg exercises can be used for training planning. The aim of this research was to examine the thigh muscle activation values during three different single leg exercises. Materials and Methods. Ten healthy male volunteers who were students of the faculty of sports sciences participated in the study. In the study, the EMG ampilitude values of the vastus medialis (VM), vastus lateralis (VL), semitendinosus (SEM) and biceps femoris (BF) muscles were examined during Step-up, Bench Squat and Airborne Lunge exercises. At the same time, Quadriceps (VM+VL): Hamstring (SEM+BF) ratios were determined. Results. Significant differences were detected in all thigh muscles in the ascent and descent phases (p<0.05). While the greatest activation for the quadriceps group was seen in the airborne lunge, the greatest activation for the hamstring group was detected in the bench squat. A statistically significant difference was found in terms of exercise practices in the quadriceps: hamstring (Q:H) ratio (F(2,18)=12.282, p=.003). It was seen that the most balanced exercise was bench squat (Q:H=2.55), and the most unbalanced exercise (agonist dominant) was airborne lunge (Q:H=5.51). Conclusions. The findings show that the exercises examined can be selected depending on the purpose of the training. While bench squats can be preferred for more balanced co-activation the airborne lunge can be preferred for dominant knee extensors.

scholarly journals Differences of Thigh Muscle Activation During Various Squat Exercise on Stable and Unstable Surfaces

2021 ◽  
Vol 30 (3) ◽  
pp. 387-395
Author(s):  
Soojin Kim ◽  
Joo-Hyun Lee ◽  
Jihye Heo ◽  
Eunwook Chang
Keyword(s):  
Muscle Activity ◽  
Repeated Measures ◽  
Muscle Activation ◽  
Vastus Lateralis ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Quadriceps Muscle ◽  
Thigh Muscle ◽  
Unstable Surface ◽  
Co Activation

PURPOSE: The purpose of this study was to compare thigh muscle activities and muscle co-activation when performing squats, wall squats, and Spanish squats on stable and unstable ground.METHODS: Twenty-two healthy male subjects (age: 22.50±2.70 years, height: 178.72±6.04 cm, mass: 76.50±6.80 kg, body mass index: 24.00±2.10 kg/m2, and Godin activity questionnaire: 56.30±24.10) voluntarily participated in the study. All of the participants performed three different squat exercises on the floor and the BOSU ball with an electromyograph attached to each participant’s quadriceps (rectus femoris, RF; vastus lateralis, VL; and vastus medialis, VM) and hamstrings (biceps femoris, BF; semitendinosus, ST; and semimembranosus, SM). Repeated measures of analysis of variance were utilized to compare muscle activity during the three squats exercises by floor type.RESULTS: RF (p<.001, η2=.689), VL (p<.001, η2=.622), and VM (p=.002, η2=.375) showed significant differences between exercises. Spanish squats yielded greater BF activity than did wall squats (p=.018, η2=.269). ST yielded greater muscle activity with the BOSU ball than on the floor (p=.018, η2=.269). Finally, there was a significant ground exercise interaction effect on the co-activation, showing greater muscle co-activation with Spanish squats on the BOSU ball compared to squats, squats on the BOSU ball, and wall squat on the BOSU ball.CONCLUSIONS: The findings of this study indicate that Spanish squats could be an effective exercise option for the facilitation of RF, VL, VM, and BF muscle activation. In particular, performing Spanish squats on an unstable surface could be useful for patients who need to improve their quadriceps muscle activation.

An Anthropometrically Parameterized Assistive Lower-limb Exoskeleton

2021 ◽  
Author(s):  
Curt Laubscher ◽  
Ryan Farris ◽  
Antonie van den Bogert ◽  
Jerzy T. Sawicki
Keyword(s):  
Lower Limb ◽  
Muscle Activation ◽  
Vastus Lateralis ◽  
Mechanical Energy ◽  
Biceps Femoris ◽  
Knee Joints ◽  
Lower Limb Exoskeleton ◽  
Hip Abduction ◽  
The Subject ◽  
Muscle Activations

Abstract This paper presents a newly developed lower-limb exoskeleton tested for walking assistance. The novel exoskeleton design methodology uses additive manufacturing and a parametrized model based on user anthropometrics to give a person-specific custom fit. The process is applied to average children and a healthy adult, and a prototype device is fabricated for the adult to validate the feasibility of the approach. The developed prototype actuates the hip and knee joints without restricting hip abduction-adduction motion. To test usability of the device and evaluate walking assistance, user torque, mechanical energy generated, and muscle activation are analyzed in an assisted condition where the subject walks on a level treadmill with the exoskeleton powered. This is compared to an unassisted condition with the exoskeleton unpowered and a baseline condition with the subject not wearing the exoskeleton. Comparing assisted to baseline conditions, torque magnitudes increased at the hip and knee, mechanical energy generated increased at the hip but decreased at the knee, and muscle activations decreased in the Biceps Femoris and increased in the Vastus Lateralis. The presented preliminary results are inconclusive on whether the newly developed exoskeleton can assist in walking though show promise for basic usability of the device.

Activation of Antagonist Knee Muscles during Isokinetic Efforts in Prepubertal and Adult Males

2005 ◽  
Vol 17 (2) ◽  
pp. 171-181 ◽  
Author(s):  
Eleni Bassa ◽  
Dimitrios Patikas ◽  
Christos Kotzamanidis
Keyword(s):  
Muscle Activation ◽  
Vastus Lateralis ◽  
Force Production ◽  
Biceps Femoris ◽  
Antagonistic Activity ◽  
Adult Males ◽  
Significant Difference ◽  
Angular Velocities ◽  
Knee Muscle ◽  
Muscle Force Production

The deficit of muscle-force production observed in children can be partly attributed to neural factors, such as an increased level of coactivation. This hypothesis, however, has not been thoroughly investigated under concentric and eccentric isokinetic conditions at different angular velocities. Thus, the purpose of this study was to examine whether prepubescent children present higher levels of activation of the antagonist knee muscles during isokinetic, concentric, and eccentric knee efforts compared with adults. Eighteen prepubertal and 13 young adult males (age: 10.9 ± 0.5 and 18.1 ± 0.1 years, respectively) performed maximal concentric and eccentric knee extensions and flexions at 45, 90, and 180 degrees/s. The vastus lateralis and biceps femoris electromyogram was recorded and the antagonist activation (coactivation) was calculated. Concentric contractions for both groups revealed significantly higher coactivation values (p < .05) compared with the eccentric conditions. Furthermore, increasing the angular velocity increased the level of coactivation significantly only during the concentric efforts for both groups. No significant difference in the antagonistic activity of the vastus lateralis and biceps femoris, however, was found between groups. Therefore, increased antagonist knee-muscle activation, which enhances joint stabilization during isokinetic concentric and eccentric effort, is similar in both prepubescent and adult males.

scholarly journals “NO LOAD” Resistance Training Promotes High Levels of Knee Extensor Muscles Activation—A Pilot Study

Diagnostics ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 526
Author(s):  
Rafael Ribeiro Alves ◽  
Carlos Alexandre Vieira ◽  
Martim Bottaro ◽  
Murilo Augusto Soares de Araújo ◽  
Daniel Costa Souza ◽  
...  
Keyword(s):  
Resistance Training ◽  
Visual Feedback ◽  
External Load ◽  
Muscle Activation ◽  
Vastus Lateralis ◽  
Load Resistance ◽  
Knee Extensors ◽  
Emg Activity ◽  
Functional Changes ◽  
Significant Difference

The present article aims to compare electromyographic (EMG) activity of the knee extensors during traditional resistance training (TRT) and no load resistance training with or without visual feedback (NL-VF and NL-NF). Sixteen healthy men (age: 25.2 ± 3.6) volunteered to participate in the study. Participants visited the laboratory on three occasions involving: (1) a 10 repetition maximum test (10 RM test), (2) familiarization and (3) performance of knee extensions using TRT, NL-VF and NL-NF in a random order, with 10 min of rest between them. TRT involved the performance of a set to momentary muscle failure using the 10 RM load. NL-NF involved the performance of 10 repetitions with no external load, but with the intention to maximally contract the muscles during the whole set. NL-VF involved the same procedure as NL-NF, but a monitor was positioned in front of the participants to provide visual feedback on the EMG activity. Peak and mean EMG activity were evaluated on the vastus medialis (VM), vastus lateralis (VL) and rectus femoris (RF). Results: there were no significant differences in VM and VL peak EMG activity among different situations. There was a significant difference for peak EMG activity for RF, where TRT resulted in higher values than NL-VF and NL-NF (p < 0.05). Higher values of mean EMG activity were found for VM, VL and RF during TRT in comparison with both NL-VF and NL-NF. Conclusions: resistance training with no external load produced high levels of peak muscle activation, independent of visual feedback, but mean activation was higher during TRT. These results suggest that training with no external load might be used as a strategy for stimulating the knee extensors when there is limited access to specialized equipment. Although the clinical applications of no load resistance training are promising, it is important to perform long-term studies to test if these acute results will reflect in muscle morphological and functional changes.

scholarly journals Muscle Activation Profiles of Lower Extremities in Different Throwing Techniques and in Jumping Performance in Elite and Novice Greek Judo Athletes

2013 ◽  
Vol 37 (1) ◽  
pp. 63-70 ◽  
Author(s):  
Georgios Zaggelidis ◽  
Savvas Lazaridis
Keyword(s):  
Muscle Activation ◽  
Vastus Lateralis ◽  
Biceps Femoris ◽  
Emg Activity ◽  
Jumping Performance ◽  
Co Activation ◽  
Vertical Jumping ◽  
Judo Athletes ◽  
Surface Electromyograms ◽  
Vertical Jumps

The aim of this study was to examine the neuromuscular adaptations of knee muscles during hip throwing techniques and vertical jumps in elite and novice Greek judokas. Ten elite and ten novice judokas performed two hip throws and different vertical jumping tasks. Surface electromyograms were recorded from vastus lateralis and biceps femoris muscles along with generated kinetics. Elite judokas revealed higher EMG activity of agonist muscles during throws and jumps but lower co-activation levels. Better jumping performance, better utilisation of the stretch-shortening cycle mechanism, higher and earlier generated pushoff forces and shorter contact time periods characterized elite judokas. Total neuromuscular activation that adopt elite judokas reveals a more mature and skill dependent strategy compared to novice ones.

scholarly journals Ankle Muscle Activations during Different Foot-Strike Patterns in Running

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3422
Author(s):  
Jian-Zhi Lin ◽  
Wen-Yu Chiu ◽  
Wei-Hsun Tai ◽  
Yu-Xiang Hong ◽  
Chung-Yu Chen
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Stance Phase ◽  
Inertial Sensors ◽  
Plantar Flexion ◽  
Intraclass Correlation ◽  
Biceps Femoris ◽  
Ankle Muscle ◽  
Foot Strike ◽  
Muscle Activations

This study analysed the landing performance and muscle activity of athletes in forefoot strike (FFS) and rearfoot strike (RFS) patterns. Ten male college participants were asked to perform two foot strikes patterns, each at a running speed of 6 km/h. Three inertial sensors and five EMG sensors as well as one 24 G accelerometer were synchronised to acquire joint kinematics parameters as well as muscle activation, respectively. In both the FFS and RFS patterns, according to the intraclass correlation coefficient, excellent reliability was found for landing performance and muscle activation. Paired t tests indicated significantly higher ankle plantar flexion in the FFS pattern. Moreover, biceps femoris (BF) and gastrocnemius medialis (GM) activation increased in the pre-stance phase of the FFS compared with that of RFS. The FFS pattern had significantly decreased tibialis anterior (TA) muscle activity compared with the RFS pattern during the pre-stance phase. The results demonstrated that the ankle strategy focused on controlling the foot strike pattern. The influence of the FFS pattern on muscle activity likely indicates that an athlete can increase both BF and GM muscles activity. Altered landing strategy in cases of FFS pattern may contribute both to the running efficiency and muscle activation of the lower extremity. Therefore, neuromuscular training and education are required to enable activation in dynamic running tasks.

Change in Shear Elastic Modulus of Thigh Muscle by Changing Muscle Length Using Ultrasound Shear Wave Elastography in Beagle Dogs

2019 ◽  
Vol 32 (06) ◽  
pp. 454-459 ◽  
Author(s):  
Miki Shimizu ◽  
Yu Ito
Keyword(s):  
Elastic Modulus ◽  
Shear Wave ◽  
Vastus Lateralis ◽  
Muscle Length ◽  
Shear Wave Elastography ◽  
Biceps Femoris ◽  
Percentage Change ◽  
Thigh Muscle ◽  
Beagle Dogs ◽  
Shear Elastic Modulus

Objectives This study investigated the relationship between the change in the shear elastic modulus and the change in muscle length using ultrasound shear wave elastography. Study Design Four thigh muscles, cranial part of the sartorius, vastus lateralis, biceps femoris and semitendinosus muscles, of 21 pelvic limbs in 12 clinically healthy Beagle dogs were used. The muscle length was estimated using a radiograph and the flexed and extended positions of the coxofemoral and stifle joints, respectively. The shear elastic modulus (kPa) was measured in two joint positions using ultrasound shear wave elastography. Shear elastic modulus was expressed as median of 10 consecutive measurements. The percentage change of elastic modulus was calculated from the shear elastic modulus in elongated condition and pre-elongated condition of muscle. Results The elastic modulus of all muscles increased when the muscle was elongated. The shear elastic modulus for both joint positions and the percentage change of the shear elastic modulus (%) in cranial part of the sartorius were highest in all muscles. Intra-observer correlation coefficient (1.2) was 0.75 to 0.96 and intra-observer correlation coefficients (2.2) was 0.46 to 0.96. Conclusion This study revealed that the shear elastic modulus of muscle was changed by the change in muscle length and increased when the muscle was elongated. Ultrasound shear wave elastography can be used to assess the elastic properties of canine muscle.

Muscle coordination in cycling: effect of surface incline and posture

1998 ◽  
Vol 85 (3) ◽  
pp. 927-934 ◽  
Author(s):  
Li Li ◽  
Graham E. Caldwell
Keyword(s):  
Lower Extremity ◽  
High Speed ◽  
Vastus Lateralis ◽  
Activity Patterns ◽  
Gluteus Maximus ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Knee Extensors ◽  
Emg Activity ◽  
Muscle Coordination

The purpose of the present study was to examine the neuromuscular modifications of cyclists to changes in grade and posture. Eight subjects were tested on a computerized ergometer under three conditions with the same work rate (250 W): pedaling on the level while seated, 8% uphill while seated, and 8% uphill while standing (ST). High-speed video was taken in conjunction with surface electromyography (EMG) of six lower extremity muscles. Results showed that rectus femoris, gluteus maximus (GM), and tibialis anterior had greater EMG magnitude in the ST condition. GM, rectus femoris, and the vastus lateralis demonstrated activity over a greater portion of the crank cycle in the ST condition. The muscle activities of gastrocnemius and biceps femoris did not exhibit profound differences among conditions. Overall, the change of cycling grade alone from 0 to 8% did not induce a significant change in neuromuscular coordination. However, the postural change from seated to ST pedaling at 8% uphill grade was accompanied by increased and/or prolonged muscle activity of hip and knee extensors. The observed EMG activity patterns were discussed with respect to lower extremity joint moments. Monoarticular extensor muscles (GM, vastus lateralis) demonstrated greater modifications in activity patterns with the change in posture compared with their biarticular counterparts. Furthermore, muscle coordination among antagonist pairs of mono- and biarticular muscles was altered in the ST condition; this finding provides support for the notion that muscles within these antagonist pairs have different functions.

scholarly journals Muscle Coactivation Before and After the Impact Phase of Running Following Isokinetic Fatigue

2011 ◽  
Vol 46 (1) ◽  
pp. 11-19 ◽  
Author(s):  
Eleftherios Kellis ◽  
Andreas Zafeiridis ◽  
Ioannis G. Amiridis
Keyword(s):  
Muscle Activation ◽  
Biceps Femoris ◽  
Knee Extension ◽  
Knee Extensors ◽  
Training Experience ◽  
Cross Sectional ◽  
Muscle Activation Patterns ◽  
Strength Capacity ◽  
Before And After ◽  
The Impact

Abstract Context: The effects of fatigue on impact loading during running are unclear, with some authors reporting increased impact forces and others reporting decreased forces. Objective: To examine the effects of isokinetic fatigue on muscle cocontraction ratios about the knee and ankle during running. Design: Cross-sectional study. Setting: Neuromechanics laboratory. Patients or Other Participants: Female middle-distance runners (age  =  21.3 ± 1.93 years) with at least 5 years of training experience. Intervention(s): Participants ran on the treadmill at 3.61 m/s before and immediately after the fatigue protocol, which consisted of consecutive, concentric knee extension-flexion at 120°/s until they could no longer produce 30% of the maximum knee-extension moment achieved in the familiarization session for 3 consecutive repetitions. Main Outcome Measure(s): Electromyographic (EMG) amplitude of the vastus medialis (VM), biceps femoris (BF), gastrocnemius (GAS), and tibialis anterior (TA) was recorded using surface electrodes. Agonist∶antagonist EMG ratios for the knee (VM∶BF) and ankle (GAS∶TA) were calculated for the preactivation (PR), initial loading response (LR1), and late loading response (LR2) phases of running. Hip-, knee-, and ankle-joint angular displacements at initial foot contact were obtained from 3-dimensional kinematic tracings. Results: Fatigue did not alter the VM∶BF EMG ratio during the PR phase (P &gt; .05), but it increased the ratio during the LR1 phase (P &lt; .05). The GAS∶TA EMG ratio increased during the LR1 phase after fatigue (P &lt; .05) but remained unchanged during the PR and LR2 phrases (P &gt; .05). Conclusions: The increased agonist EMG activation, coupled with reduced antagonist EMG activation after impact, indicates that the acute decrease in muscle strength capacity of the knee extensors and flexors results in altered muscle-activation patterns about the knee and ankle before and after foot impact.

scholarly journals Effects of Short-Term Training With Uncoupled Cranks in Trained Cyclists

2012 ◽  
Vol 7 (2) ◽  
pp. 113-120 ◽  
Author(s):  
Jack M. Burns ◽  
Jeremiah J. Peiffer ◽  
Chris R. Abbiss ◽  
Greig Watson ◽  
Angus Burnett ◽  
...  
Keyword(s):  
Muscle Activation ◽  
Vastus Lateralis ◽  
Biceps Femoris ◽  
Training Group ◽  
Recovery Phase ◽  
Muscle Recruitment ◽  
Short Term ◽  
Activation Patterns ◽  
Gross Efficiency ◽  
Muscle Activation Patterns

Purpose:Manufacturers of uncoupled cycling cranks claim that their use will increase economy of motion and gross efficiency. Purportedly, this occurs by altering the muscle-recruitment patterns contributing to the resistive forces occurring during the recovery phase of the pedal stroke. Uncoupled cranks use an independent-clutch design by which each leg cycles independently of the other (ie, the cranks are not fixed together). However, research examining the efficacy of training with uncoupled cranks is equivocal. The purpose of this study was to determine the effect of short-term training with uncoupled cranks on the performance-related variables economy of motion, gross efficiency, maximal oxygen uptake (VO2max), and muscle-activation patterns.Methods:Sixteen trained cyclists were matched-paired into either an uncoupled-crank or a normal-crank training group. Both groups performed 5 wk of training on their assigned cranks. Before and after training, participants completed a graded exercise test using normal cranks. Expired gases were collected to determine economy of motion, gross efficiency, and VO2max, while integrated electromyography (iEMG) was used to examine muscle-activation patterns of the vastus lateralis, biceps femoris, and gastrocnemius.Results:No significant changes between groups were observed for economy of motion, gross efficiency, VO2max, or iEMG in the uncoupled- or normal-crank group.Conclusions:Five weeks of training with uncoupled cycling cranks had no effect on economy of motion, gross efficiency, muscle recruitment, or VO2max compared with training on normal cranks.

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