scholarly journals Effects of the back-squat exercise on lower limb myoelectric activity in trained men: a systematic review

2021 ◽  
Vol 20 (1) ◽  
pp. 83-92
Author(s):  
Rogério Santos Aguiar ◽  
Juliana Brandão Pinto de Castro ◽  
Andressa Oliveira Barros dos Santos Santos ◽  
Giullio César Pereira Salustiano Mallen da Silva ◽  
Fabiana Rodrigues Scartoni ◽  
...  
Keyword(s):  
Systematic Review ◽  
Resistance Training ◽  
Lower Limb ◽  
Vastus Lateralis ◽  
Experimental Studies ◽  
Gluteus Maximus ◽  
Rectus Femoris ◽  
Myoelectric Activity ◽  
Back Squat ◽  
Squat Exercise

Aim: The aim of this study was to describe the effects of the back-squat exercise on the lower limb myoelectric activity in trained men. Methods: We conducted a systematic review following the recommendations of PRISMA. Medline (PubMed), Scielo, Scopus, SPORTDiscus, and Lilacs databases were searched. The search terms included electromyography, exercise, resistance training, and squat. We included experimental studies that described the back-squat exercise using surface electromyography (EMG) in men experienced in resistance training and back squat exercise at angles from 60º to 90º. Results: Eight studies met the inclusion criteria. The interventions of the included studies ranged from 2 to 7 days. The protocols demonstrated to improve the neuromuscular system and to provide greater acquisition of strength in the muscles involved in performing the back-squat exercise (p < 0.05). Thirty-seven muscles were analyzed, with a predominance of the vastus lateralis, vastus medialis, gluteus maximus, and rectus femoris muscles. Conclusion: The studies investigated in this review showed that the back-squat exercise at angles from 60º to 90º increased the lower limb myoelectric activity recorded in loads of 30% and 100% of 1RM in men experienced in resistance training. However, more studies with higher methodological quality are needed in the analysis of the squat exercise to reduce the risk of bias.

scholarly journals Muscle Activation Differs between Three Different Knee Joint-Angle Positions during a Maximal Isometric Back Squat Exercise

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Paulo Henrique Marchetti ◽  
Josinaldo Jarbas da Silva ◽  
Brad Jon Schoenfeld ◽  
Priscyla Silva Monteiro Nardi ◽  
Silvio Luis Pecoraro ◽  
...  
Keyword(s):  
Knee Joint ◽  
Muscle Activation ◽  
Specific Activity ◽  
Vastus Lateralis ◽  
Gluteus Maximus ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Joint Angles ◽  
Back Squat ◽  
Squat Exercise

The purpose of this study was to compare muscle activation of the lower limb muscles when performing a maximal isometric back squat exercise over three different positions. Fifteen young, healthy, resistance-trained men performed an isometric back squat at three knee joint angles (20°, 90°, and 140°) in a randomized, counterbalanced fashion. Surface electromyography was used to measure muscle activation of the vastus lateralis (VL), vastus medialis (VM), rectus femoris (RF), biceps femoris (BF), semitendinosus (ST), and gluteus maximus (GM). In general, muscle activity was the highest at 90° for the three quadriceps muscles, yet differences in muscle activation between knee angles were muscle specific. Activity of the GM was significantly greater at 20° and 90° compared to 140°. The BF and ST displayed similar activation at all joint angles. In conclusion, knee position alters muscles activation of the quadriceps and gluteus maximus muscles. An isometric back squat at 90° generates the highest overall muscle activation, yet an isometric back squat at 140° generates the lowest overall muscle activation of the VL and GM only.

Analysis of Lower Limb Muscle Function in Ergometer Rowing

1988 ◽  
Vol 4 (4) ◽  
pp. 315-325 ◽  
Author(s):  
J.-M. John Wilson ◽  
D. Gordon E. Robertson ◽  
J. Peter Stothart
Keyword(s):  
Lower Limb ◽  
Muscle Function ◽  
Tibialis Anterior ◽  
Vastus Lateralis ◽  
Gluteus Maximus ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Peak Force ◽  
Lower Limb Muscle ◽  
Limb Muscle

In an effort to seek further understanding of lower limb muscle function in the rowing movement, an electromyographic analysis was undertaken of rowers rowing on a Gjessing ergometer. A strain gauged transducer was inserted in the ergometer linkage between handle and flywheel to detect pulling force. Electrodes were placed on the following lower limb muscles: gluteus maximus, biceps femoris, rectus femoris, vastus lateralis, gastrocnemius, and tibialis anterior. Linear envelope electromyograms from each muscle and the force signals were sampled synchronously at 50 Hz. The results indicated that all six muscles were active from catch to finish of the drive phase. Biceps femoris, gluteus maximus, gastrocnemius, and vastus lateralis all began their activity at or just prior to catch and reached maximal excitation near peak force of the stroke. Rectus femoris and tibialis anterior activity began prior to the catch and reached maximal excitation subsequent to peak force. The coactivation of the five leg muscles, of which four were biarticular, included potentially antagonistic actions that would cancel each other’s effects. Clearly, however, other explanations must be considered. Both gastrocnemius and biceps femoris have been shown to act as knee extensors and may do so in the case of the rowing action. Furthermore, rectus femoris may act with unchanging length as a knee extensor by functioning as a rigid link between the pelvis and tibia. In this manner, energy created by the hip extensors is transferred across the knee joint via the isometrically contracting rectus femoris muscle.

scholarly journals Effects of Stance Width and Barbell Placement on Kinematics, Kinetics, and Myoelectric Activity in Back Squats

2021 ◽  
Vol 3 ◽  
Author(s):  
Stian Larsen ◽  
Eirik Kristiansen ◽  
Eric Helms ◽  
Roland van den Tillaar
Keyword(s):  
Body Mass ◽  
Vastus Lateralis ◽  
Gluteus Maximus ◽  
The Other ◽  
Knee Extensors ◽  
Myoelectric Activity ◽  
Plantar Flexors ◽  
Total Moment ◽  
Repetition Maximum ◽  
Back Squat

Barbell placement and stance width both affect lifting performance in the back squat around the sticking region. However, little is known about how these squat conditions separately could affect the lifting performance. Therefore, this study investigated the effects of stance width and barbell placement upon kinematics, kinetics, and myoelectric activity around the sticking region during a three-repetition maximum back squat. Nine men and nine women (body mass: 76.2 ±11.1, age: 24.9 ± 2.6) performed back squats with four different techniques, such as: high-bar narrow stance (HBNS), high-bar wide stance, low-bar narrow stance, and low-bar wide stance where they lifted 99.2 ± 23.6, 92.9 ± 23.6, 102.5 ± 24.7, and 97.1 ± 25.6 kg, respectively. The main findings were that squatting with a low-bar wide stance condition resulted in larger hip contributions to the total moment than the other squat conditions, whereas squatting with an HBNS resulted in greater knee contributions to the total moment together with higher vastus lateralis and less gluteus maximus myoelectric activity. Our findings suggest that training with an HBNS could be beneficial when targeting the knee extensors and plantar flexors, whereas a low-bar wide stance could be beneficial when targeting the hip extensors.

Lunges activate the gluteus maximus muscles more than back squats when both exercises are standardized

2021 ◽  
pp. 1-7
Author(s):  
Rodrigo Ramalho Aniceto ◽  
André Luiz Torres Pirauá ◽  
Leonardo da Silva Leandro ◽  
Hélen Cristina Ferreira da Silva ◽  
Diego Mesquita Silva ◽  
...  
Keyword(s):  
Resistance Training ◽  
Vastus Lateralis ◽  
Knee Extensor ◽  
Gluteus Maximus ◽  
Biceps Femoris ◽  
Lower Limbs ◽  
Emg Activity ◽  
Flexor Muscle ◽  
Back Squat ◽  
Trunk Inclination

BACKGROUND: Squats are considered one of the main exercises for the lower limbs and are used in resistance training under different contexts, including rehabilitation and sports performance. OBJECTIVE: To compare the EMG activity of different muscles in back squat and lunge exercises in trained women. METHODS: Ten healthy women experienced in resistance training performed back squat and lunge exercises on a Smith machine (total work: 70% of 1RM, 1 set, 10 repetitions and 2-s/2-s of execution speed) with an interval of 20-min between exercises. Both exercises were standardized in relation to the trunk inclination and were performed with an erect trunk parallel to the cursor of the guided bar. RESULTS: The EMG activity of the vastus medialis (VM), vastus lateralis (VL), biceps femoris (BF), and gluteus maximus (GM) were analyzed. There were no significant differences in the EMG activity of the VM, VL, and BF muscles between the back squat and lunge exercises (P> 0.05); however, GM activation was greater during the lunge exercise (effect size = 1.15; P= 0.001). CONCLUSIONS: Lunges were more effective in recruiting the GM when compared to back squats. However, both exercises can be recommended when the goal is knee extensor and flexor muscle activity.

scholarly journals Electromyographic Comparison of Five Lower-Limb Muscles between Single- and Multi-Joint Exercises among Trained Men

2021 ◽  
pp. 56-61
Author(s):  
Nicolay Stien ◽  
Atle Hole Saeterbakken ◽  
Vidar Andersen
Keyword(s):  
Resistance Training ◽  
Vastus Lateralis ◽  
Gluteus Maximus ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Knee Extension ◽  
Knee Extensors ◽  
Vastus Medialis ◽  
Leg Press ◽  
Emg Amplitude

Resistance-training exercises can be classified as either single- or multi-joint exercises and differences in surface electromyography (EMG) amplitude between the two training methods may identify which muscles can benefit from either training modality. This study aimed to compare the surface EMG amplitude of five hip- and knee extensors during one multi-joint (leg press) and two single-joint exercises (knee extension and kickback). Fifteen resistance-trained men completed one familiarization session to determine their unilateral six repetitions maximum (6RM) in the three exercises. During the following experimental session, EMG amplitudes of the vastus lateralis, vastus medialis, rectus femoris, gluteus maximus and biceps femoris of the left leg were measured while performing three repetitions on their respective 6RM loads. The multi-joint exercise leg press produced higher EMG amplitude of the vastus lateralis (ES = 0.92, p = 0.003) than the single-joint exercise knee extension, whereas the rectus femoris demonstrated higher EMG amplitude during the knee extension (ES = 0.93, p = 0.005). The biceps femoris EMG amplitude was higher during the single-joint exercise kickback compared to the leg press (ES = 2.27, p < 0.001), while no significant differences in gluteus maximus (ES = 0.08, p = 0.898) or vastus medialis (ES = 0.056, p = 0.025 were observed between exercises. The difference in EMG amplitude between single- and multi-joint exercises appears to vary depending on the specific exercises and the muscle groups tested. Leg press is a viable and time-efficient option for targeting several hip- and knee extensors during resistance training of the lower limbs, but the single-joint exercises may be preferable for targeting the rectus femoris and biceps femoris.

scholarly journals Comparison of Peak Ground Reaction Force, Joint Kinetics and Kinematics, and Muscle Activity Between a Flexible and Steel Barbell During the Back Squat Exercise

2019 ◽  
Vol 68 (1) ◽  
pp. 99-108
Author(s):  
Randolph E. Hutchison ◽  
Anthony Caterisano
Keyword(s):  
Muscle Activity ◽  
Vastus Lateralis ◽  
Rectus Femoris ◽  
Rectus Abdominis ◽  
American Football ◽  
Ground Reaction Forces ◽  
Back Squat ◽  
Squat Exercise ◽  
Reaction Forces ◽  
External Oblique

AbstractThe flexible barbell is purported to improve training gains compared with an Olympic steel barbell (SB) during the back squat exercise with Division I collegiate American football programs. The two bars loaded at 30% 1-repetition maximum were compared with ten trained Division I American football players (n = 10; age = 19.5 years; body mass = 89.4 kg; body height = 182.0 cm) completing 10 repetitions of the back squat exercise. Analysis included integrated-peak values of electromyography of the rectus femoris, biceps femoris, rectus abdominis, erector spinae, external oblique, vastus lateralis, ground reaction forces, and joint kinematics and kinetics of the hip, knee, and ankle. The flexible bar elicited significant increases in peak joint kinetics (Hip Moment: 229 ± 54 Nm vs. 209 ± 52 Nm; Hip Power: 494 ± 151 W vs. 382 ± 134 W; Knee Power: 305 ± 108 W vs. 241 ± 63 W), peak vertical ground reaction forces (1195 ± 209 N vs. 1120 ± 203 N), and muscle activity (Vastus Lateralis: 75.7 vs. 66.5%, Rectus Abdominis: 190 vs. 115%, Rectus Femoris: 69.8 vs. 59.9%, External Oblique: 115 vs. 69.0%). Greater vertical ground reaction forces, hip moment, hip power, knee power, and muscle activity of the vastus lateralis, rectus abdominis, rectus femoris, and external oblique suggest the FB provides biomechanical and physiological mechanisms for training gains over the SB for 30% of 1-repetition maximum loads.

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 Differences in Simulated EMG Activities between a Non-Rotational Shot and an Ordinary Instep Kick Identified by Principal Component Analysis

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 154
Author(s):  
Tasuku Miyoshi ◽  
Yasuhisa Kamada ◽  
Yoshiyuki Kobayashi
Keyword(s):  
Principal Component Analysis ◽  
Vastus Lateralis ◽  
Gluteus Maximus ◽  
Principal Component ◽  
Rectus Femoris ◽  
Component Analysis ◽  
Vastus Intermedius ◽  
Longus Muscle ◽  
Instep Kick ◽  
Tensor Fasciae Latae

The aim of this study was to clarify the major differences in the electromyographic (EMG) activities in the hip joint required to achieve a non-rotational (NR) shot as compared with an instep kick from the spatiotemporal data. For this purpose, simulated EMG activities obtained from NR shots and instep kicks were analyzed using principal component analysis (PCA). The PCA was conducted using an input matrix constructed from the time-normalized average and the standard deviation of the EMG activities (101 data x (15 muscles; iliacus, gluteus maximus, rectus femoris, biceos femoris, vastus lateralis, vastus medialis, vastus intermedius, semimembranosus, semitendinosus, sartorius, tensor fasciae latae muscle, adductor magnus muscle, adductor longus muscle, gasctrocnemius, and tibialis anterior)). The PCA revealed that the 3rd, 4th and 8th principal component vectors (PCVs) of the 10 generated PCVs were related to achieving the NR shot (p < 0.05).

scholarly journals Neural inhibition during maximal eccentric and concentric quadriceps contraction: effects of resistance training

2000 ◽  
Vol 89 (6) ◽  
pp. 2249-2257 ◽  
Author(s):  
P. Aagaard ◽  
E. B. Simonsen ◽  
J. L. Andersen ◽  
S. P. Magnusson ◽  
J. Halkjær-Kristensen ◽  
...  
Keyword(s):  
Resistance Training ◽  
Vastus Lateralis ◽  
Rectus Femoris ◽  
Quadriceps Strength ◽  
Electromyographic Activity ◽  
Neuromuscular Activation ◽  
Concentric Contractions ◽  
Power Frequency ◽  
Heavy Resistance Training ◽  
Median Power Frequency

Despite full voluntary effort, neuromuscular activation of the quadriceps femoris muscle appears inhibited during slow concentric and eccentric contractions. Our aim was to compare neuromuscular activation during maximal voluntary concentric and eccentric quadriceps contractions, hypothesizing that inhibition of neuromuscular activation diminishes with resistance training. In 15 men, pretraining electromyographic activity of the quadriceps muscles [vastus medialis (VM), vastus lateralis (VL), and rectus femoris (RF)] was 17–36% lower during slow and fast (30 and 240°/s) eccentric and slow concentric contractions compared with fast concentric contractions. After 14 wk of heavy resistance training, neuromuscular inhibition was reduced for VL and VM and was completely removed for RF. Concurrently, electromyographic activity increased 21–52, 22–29, and 16–32% for VL, VM, and RF, respectively. In addition, median power frequency decreased for VL and RF. Eccentric quadriceps strength increased 15–17%, whereas slow and fast concentric strength increased 15 and 8%, respectively. Pre- and posttraining median power frequency did not differ between eccentric and concentric contractions. In conclusion, quadriceps motoneuron activation was lower during maximal voluntary eccentric and slow concentric contractions compared with during fast concentric contraction in untrained subjects, and, after heavy resistance training, this inhibition in neuromuscular activation was reduced.

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