Effect of Absolute and Relative Loading on Muscle Activity During Stable and Unstable Squatting

2010 ◽  
Vol 5 (2) ◽  
pp. 177-183 ◽  
Author(s):  
Jeffrey M. McBride ◽  
Tony R. Larkin ◽  
Andrea M. Dayne ◽  
Tracie L. Haines ◽  
Tyler J. Kirby
Keyword(s):  
Body Mass ◽  
Muscle Activity ◽  
Vastus Lateralis ◽  
Force Plate ◽  
Rest Period ◽  
Biceps Femoris ◽  
Erector Spinae ◽  
Repetition Maximum ◽  
Maximum Test ◽  
Significant Difference

Purpose:The purpose of this investigation was to determine the effect of stable and unstable conditions on one repetition maximum strength and muscle activity during dynamic squatting using absolute and relative loading.Methods:Ten recreationally weight-trained males participated in this study (age = 24.1 ± 2.0 y, height = 178.0 ± 5.6 cm, body mass = 83.7 ± 13.4 kg, 1RM/body mass = 1.53 ± 0.31), which involved two laboratory sessions separated by 1 wk. Linear position transducers were used to track bar displacement while subjects stood on a force plate for all trials. Vastus lateralis (VL), biceps femoris (BF) and erector spinae (L1) muscle activity (average integrated EMG [IEMG]) was also recorded during all trials. During the frst session subjects complete a one repetition maximum test in a stable dynamic squat (S1RM = 128.0 ± 31.4 kg) and an unstable dynamic squat (U1RM = 83.8 ± 17.3 kg) in a randomized order with a 30-min rest period between conditions. The second session consisted of the performance of three trials each for 12 different conditions (unstable and stable squats using three different absolute loads [six conditions] and unstable and stable squats using three different relative loads [six conditions]).Results:Results revealed a statistically significant difference between S1RM and U1RM values (P < .05). The stable trials resulted in the same or a significantly higher value for VL, BF and L1 muscle activity in comparison with the unstable trials for all twelve conditions.Conclusions:Unstable squatting is of equal or less (depending on the loading condition) benefit to improving or maximizing muscle activity during resistance exercise.

A Comparison of Gluteus Maximus, Biceps Femoris, and Vastus Lateralis Electromyography Amplitude in the Parallel, Full, and Front Squat Variations in Resistance-Trained Females

2016 ◽  
Vol 32 (1) ◽  
pp. 16-22 ◽  
Author(s):  
Bret Contreras ◽  
Andrew D. Vigotsky ◽  
Brad J. Schoenfeld ◽  
Chris Beardsley ◽  
John Cronin
Keyword(s):  
Range Of Motion ◽  
Body Mass ◽  
Training Stimulus ◽  
Vastus Lateralis ◽  
Full Range ◽  
Gluteus Maximus ◽  
Biceps Femoris ◽  
Repetition Maximum ◽  
Training Adaptations ◽  
Back Squat

Front, full, and parallel squats are some of the most popular squat variations. The purpose of this investigation was to compare mean and peak electromyography (EMG) amplitude of the upper gluteus maximus, lower gluteus maximus, biceps femoris, and vastus lateralis of front, full, and parallel squats. Thirteen healthy women (age = 28.9 ± 5.1 y; height = 164 ± 6.3 cm; body mass = 58.2 ± 6.4 kg) performed 10 repetitions of their estimated 10-repetition maximum of each respective variation. There were no statistical (P = .05) differences between full, front, and parallel squats in any of the tested muscles. Given these findings, it can be concluded that the front, full, or parallel squat can be performed for similar EMG amplitudes. However, given the results of previous research, it is recommended that individuals use a full range of motion when squatting, assuming full range can be safely achieved, to promote more favorable training adaptations. Furthermore, despite requiring lighter loads, the front squat may provide a similar training stimulus to the back squat.

Comparison of Hip- and Back-Muscle Activity and Pelvic Compensation in Healthy Subjects During 3 Different Prone Table Hip-Extension Exercises

2017 ◽  
Vol 26 (4) ◽  
pp. 216-222 ◽  
Author(s):  
In-cheol Jeon ◽  
Oh-yun Kwon ◽  
Jong-hyuck Weon ◽  
Ui-jae Hwang ◽  
Sung-hoon Jung
Keyword(s):  
Outcome Measures ◽  
Muscle Activity ◽  
Repeated Measures ◽  
Motion Tracking ◽  
Gluteus Maximus ◽  
Biceps Femoris ◽  
Erector Spinae ◽  
Repeated Measure ◽  
Significant Difference ◽  
Hip Extension

Context:Prone hip extension has been recommended for strengthening the back and hip muscles. Previous studies have investigated prone hip extension conducted with subjects on the floor in the prone position. However, no study has compared 3 different table hip-extension (THE) positions in terms of the activities of the back- and hip-joint muscles with lumbopelvic motion.Objective:To identify more effective exercises for strengthening the gluteus maximus (GM) by comparing 3 different exercises (THE alone, THE with the abdominal drawing-in maneuver [THEA], and THEA with chair support under the knee [THEAC]) based on electromyographic muscle activity and pelvic compensation.Design:Repeated-measure within-subject intervention.Setting:University research laboratory.Participants:16 healthy men.Main Outcome Measures:Surface electromyography (EMG) was used to obtain data on the GM, erector spinae (ES), multifidus, biceps femoris (BF), and semitendinosus (ST). Pelvic compensation was monitored using an electromagnetic motion-tracking device. Exertion during each exercise was recorded. Any significant difference in electromyographic muscle activity and pelvic motion among the 3 conditions (THE vs THEA vs THEAC) was assessed using a 1-way repeated-measures analysis of variance (ANOVA) with Bonferroni post hoc test.Results:The muscle activities recorded by EMG differed significantly among the 3 exercises (P < .01). GM activity was increased significantly during THEAC (P < .01). There was a significant difference in lumbopelvic kinematics in terms of anterior tilting (F = 19.49, P < .01) and rotation (F= 27.38, P < .01) among the 3 exercises.Conclusions:The THEAC exercise was the most effective for strengthening the GM without overactivity of the ES, BF, and ST muscles and lumbopelvic compensation compared with THE and THEA.

A Comparison of Gluteus Maximus, Biceps Femoris, and Vastus Lateralis Electromyography Amplitude for the Barbell, Band, and American Hip Thrust Variations

2016 ◽  
Vol 32 (3) ◽  
pp. 254-260 ◽  
Author(s):  
Bret Contreras ◽  
Andrew D. Vigotsky ◽  
Brad J. Schoenfeld ◽  
Chris Beardsley ◽  
John Cronin
Keyword(s):  
Experimental Study ◽  
Body Mass ◽  
Vastus Lateralis ◽  
Gluteus Maximus ◽  
Biceps Femoris ◽  
Sport Performance ◽  
Repetition Maximum ◽  
Emg Amplitude ◽  
Healthy Female ◽  
Female Subjects

Bridging exercise variations are well researched and commonly employed for both rehabilitation and sport performance. However, resisted bridge exercise variations have not yet been compared in a controlled experimental study. Therefore, the purpose of this study was to compare the differences in upper and lower gluteus maximus, biceps femoris, and vastus lateralis electromyography (EMG) amplitude for the barbell, band, and American hip thrust variations. Thirteen healthy female subjects (age = 28.9 y; height = 164.3 cm; body mass = 58.2 kg) familiar with the hip thrust performed 10 repetitions of their 10-repetition maximum of each variation in a counterbalanced and randomized order. The barbell hip thrust variation elicited statistically greater mean gluteus maximus EMG amplitude than the American and band hip thrusts, and statistically greater peak gluteus maximus EMG amplitude than the band hip thrust (P ≤ .05), but no other statistical differences were observed. It is recommended that resisted bridging exercise be prescribed according to the individual’s preferences and desired outcomes.

Are leg electromyogram profiles in squat is symetrical? (Case study)

2017 ◽  
Vol 27 (78) ◽  
pp. 65-74
Author(s):  
Krzysztof Kmiecik ◽  
Henryk Król ◽  
Grzegorz Sobota
Keyword(s):  
Body Mass ◽  
Body Height ◽  
Force Plate ◽  
Gluteus Maximus ◽  
Movement Patterns ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Erector Spinae ◽  
Measuring System ◽  
Load Increase

The action of the central nervous system that controls neuromuscular functions reflect electromyograms (EMGs) profiles of muscle activity of the basic muscles. However, there seems to be a relationship between the EMGs profiles and the movement patterns (e.g., values of extremity joins angles). We want to find out how changes EMG profiles and movement patterns of the squat movement with increasing loads and especially we want to determine degree of symmetry of selected homologous muscles. Due to the lack of critical information addressing symmetry, we studied the EMG profiles of six homologous leg muscles (i.e. tibialis anterior, gastrocnemius, rectus femoris, biceps femoris, gluteus maximus and erector spinae) during squat movement depending on load size. For this purpose we checked the usefulness of the multimodular measuring system (SMART-E, BTS) and force plate Kistler. Smart Analyser software was used to create a database allowing the chosen EMG profiles and movement patterns to be compared. In this study participated eleven healthy man, however two were selected for analysis. The first of subject was 36 years (body mass 82 kg; body height 180 cm; 1RM in full squat 140 kg). The second one was 28 years (body mass 90 kg; body height 183 cm; 1RM in full squat 110 kg). The subjects performed consecutive sets of a single repetition of full squat with the increasing load (70, 80, 90 and 100% 1RM the anticipated maximum weight), until the appointment of one repetition maximum. For analysis, however, only samples with moderate and maximal loads (70% and 100% 1RM, respectively) were selected. The sum of the differences in normalized amplitude values of individual pairs of homologous muscles was taken as a measure of symmetry/asymmetry of the EMG profile. The load increase of the squat contributed to the increase asymmetry of the profiles of pairs homologous muscles of the lower extremities. Greater asymmetry of subject A.M. in a squat with a load of 100% 1RM resulted that the fluidity of the movement was worsened.

scholarly journals The Piezo-resistive MC Sensor is a Fast and Accurate Sensor for the Measurement of Mechanical Muscle Activity

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 2108 ◽  
Author(s):  
Andrej Meglič ◽  
Mojca Uršič ◽  
Aleš Škorjanc ◽  
Srđan Đorđević ◽  
Gregor Belušič
Keyword(s):  
Muscle Activity ◽  
Skeletal Muscles ◽  
Time Course ◽  
Vastus Lateralis ◽  
Initial Pressure ◽  
Rectus Femoris ◽  
Signal Amplitude ◽  
Biceps Femoris ◽  
Erector Spinae ◽  
Vastus Medialis

A piezo-resistive muscle contraction (MC) sensor was used to assess the contractile properties of seven human skeletal muscles (vastus medialis, rectus femoris, vastus lateralis, gastrocnemius medialis, biceps femoris, erector spinae) during electrically stimulated isometric contraction. The sensor was affixed to the skin directly above the muscle centre. The length of the adjustable sensor tip (3, 4.5 and 6 mm) determined the depth of the tip in the tissue and thus the initial pressure on the skin, fatty and muscle tissue. The depth of the tip increased the signal amplitude and slightly sped up the time course of the signal by shortening the delay time. The MC sensor readings were compared to tensiomyographic (TMG) measurements. The signals obtained by MC only partially matched the TMG measurements, largely due to the faster response time of the MC sensor.

scholarly journals Optimizing athlete assessment of maximal force and rate of development: A comparison of the isometric squat and mid-thigh pull

2020 ◽  
Author(s):  
Joao Renato Silva ◽  
Vasileios Sideris ◽  
Bryna C.R. Chrismas ◽  
Paul J. Read
Keyword(s):  
Muscle Activity ◽  
Vastus Lateralis ◽  
Gluteus Maximus ◽  
Biceps Femoris ◽  
Peak Force ◽  
Erector Spinae ◽  
Vastus Medialis ◽  
Rate Of Development ◽  
Hamstring Muscles ◽  
Force Time

ABSTRACTThis study compared force-time characteristics and muscle activity between the isometric squat (ISQ) and mid-thigh pull (IMTP) in both bilateral (ISQBI and IMTPBI) and unilateral (ISQUNI and IMTPUNI) stance. Peak force (PF), rate-of-force (RFD) (e.g. 0-300ms) and EMG of the multifidus, erector spinae (ES), gluteus maximus (GM), biceps femoris (BF), semitendinosus (ST), vastus medialis (VM), vastus lateralis (VL) and soleus were recorded in ten recreationally trained males. PF was significantly greater during the ISQBI vs. IMTPBI (p=0.016, ES=1.08) but not in the unilateral test mode although effects remained moderate (ES=0.62). A trend indicated heightened RFD300ms (p = 0.083; ES=0.81) during the IMTPBI vs. the ISQBI, but these effects were smaller in the unilateral test (ES = 0.51). Greater (p<0.0001) EMG for VL (ES=1.00-1.13) and VM were recorded during the ISQ compared to IMTP modes in both modes (ES = 0.97 – 1.18). Greater BF EMG (p = 0.030, ES = 0.31) was shown in IMTPBI vs. ISQBI and these effects were stronger in the unilateral modes (p = < 0.05; ES = 0.81 – 0.83). Significantly greater ST activation was shown in both IMTPUNI (p < 0.05; ES = 0.69-0.76) and IMTPBI (p < 0.001; ES = 1.08). These findings indicate that ISQ results in elevated PF, whereas, RFD is heightened during the IMTP and these differences are more pronounced in bilateral modes. Greater activation of the quadriceps and hamstring muscles are expected in ISQ and IMPT respectively.

scholarly journals Using a Back Exoskeleton During Industrial and Functional Tasks—Effects on Muscle Activity, Posture, Performance, Usability, and Wearer Discomfort in a Laboratory Trial

2021 ◽  
pp. 001872082110072
Author(s):  
Tessy Luger ◽  
Mona Bär ◽  
Robert Seibt ◽  
Monika A. Rieger ◽  
Benjamin Steinhilber
Keyword(s):  
Heart Rate ◽  
Muscle Activity ◽  
Vastus Lateralis ◽  
Erector Spinae ◽  
Stair Climbing ◽  
Trunk Flexion ◽  
User Friendliness ◽  
Timed Up And Go ◽  
System Usability Scale ◽  
Task Accomplishment

Objective To investigate the effect of using a passive back-support exoskeleton (Laevo V2.56) on muscle activity, posture, heart rate, performance, usability, and wearer comfort during a course of three industrial tasks (COU; exoskeleton worn, turned-on), stair climbing test (SCT; exoskeleton worn, turned-off), timed-up-and-go test (TUG; exoskeleton worn, turned-off) compared to no exoskeleton. Background Back-support exoskeletons have the potential to reduce work-related physical demands. Methods Thirty-six men participated. Activity of erector spinae (ES), biceps femoris (BF), rectus abdominis (RA), vastus lateralis (VL), gastrocnemius medialis (GM), trapezius descendens (TD) was recorded by electromyography; posture by trunk, hip, knee flexion angles; heart rate by electrocardiography; performance by time-to-task accomplishment (s) and perceived task difficulty (100-mm visual analogue scale; VAS); usability by the System Usability Scale (SUS) and all items belonging to domains skepticism and user-friendliness of the Technology Usage Inventory; wearer comfort by the 100-mm VAS. Results During parts of COU, using the exoskeleton decreased ES and BF activity and trunk flexion, and increased RA, GM, and TD activity, knee and hip flexion. Wearing the exoskeleton increased time-to-task accomplishment of SCT, TUG, and COU and perceived difficulty of SCT and TUG. Average SUS was 75.4, skepticism 11.5/28.0, user-friendliness 18.0/21.0, wearer comfort 31.1 mm. Conclusion Using the exoskeleton modified muscle activity and posture depending on the task applied, slightly impaired performance, and was evaluated mildly uncomfortable. Application These outcomes require investigating the effects of this passive back-supporting exoskeleton in longitudinal studies with longer operating times, providing better insights for guiding their application in real work settings.

Validation and comparison of trunk muscle activities in male participants during exercise using an innovative device and abdominal bracing maneuvers

2021 ◽  
pp. 1-8
Author(s):  
Yuki Kurokawa ◽  
Satoshi Kato ◽  
Satoru Demura ◽  
Kazuya Shinmura ◽  
Noriaki Yokogawa ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Voluntary Contraction ◽  
Trunk Muscle ◽  
Erector Spinae ◽  
Trunk Muscles ◽  
Activity Levels ◽  
Significant Difference ◽  
External Oblique ◽  
Internal Oblique

BACKGROUND: Abdominal bracing is effective in strengthening the trunk muscles; however, assessing performance can be challenging. We created a device for performing abdominal trunk muscle exercises. The effectiveness of this device has not yet been evaluated or compared OBJECTIVE: We aimed to quantify muscle activity levels during exercise using our innovative device and to compare them with muscle activation during abdominal bracing maneuvers. METHODS: This study included 10 men who performed abdominal bracing exercises and exercises using our device. We measured surface electromyogram (EMG) activities of the rectus abdominis (RA), external oblique, internal oblique (IO), and erector spinae (ES) muscles in each of the exercises. The EMG data were normalized to those recorded during maximal voluntary contraction (%EMGmax). RESULTS: During the bracing exercise, the %EMGmax of IO was significantly higher than that of RA and ES (p< 0.05), whereas during the exercises using the device, the %EMGmax of IO was significantly higher than that of ES (p< 0.05). No significant difference was observed in the %EMGmax of any muscle between bracing exercises and the exercises using the device (p= 0.13–0.95). CONCLUSIONS: The use of our innovative device results in comparable activation to that observed during abdominal bracing.

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.

Effects of surface grade on proximal hindlimb muscle strain and activation during rat locomotion

2002 ◽  
Vol 93 (5) ◽  
pp. 1731-1743 ◽  
Author(s):  
Gary B. Gillis ◽  
Andrew A. Biewener
Keyword(s):  
Muscle Activity ◽  
Vastus Lateralis ◽  
Biceps Femoris ◽  
Muscle Strain ◽  
Activation Patterns ◽  
Rat Muscle ◽  
High Speeds ◽  
Hindlimb Muscle ◽  
Limb Muscles

Sonomicrometry and electromyography were used to determine how surface grade influences strain and activation patterns in the biceps femoris and vastus lateralis of the rat. Muscle activity is generally present during much of stance and is most intense on an incline, intermediate on the level, and lowest on a decline, where the biceps remains inactive except at high speeds. Biceps fascicles shorten during stance, with strains ranging from 0.07–0.30 depending on individual, gait, and grade. Shortening strains vary significantly among grades ( P = 0.05) and average 0.21, 0.16, and 0.14 for incline, level, and decline walking, respectively; similar trends are present during trotting and galloping. Vastus fascicles are stretched while active over the first half of stance on all grades, and then typically shorten over the second half of stance. Late-stance shortening is highest during galloping, averaging 0.14, 0.10, and 0.02 in the leading limb on incline, level, and decline surfaces, respectively. Our results suggest that modulation of strain and activation in these proximal limb muscles is important for accommodating different surface grades.

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