A comparison of muscle activity of the dominant and non-dominant side of the body during low versus high loaded bench press exercise performed to muscular failure

The Effect of Different Weight Plate Widths (Bumper vs. Standard) on the Biomechanics of the Bench Press

ABSTRACT

Fiedler, MJ, Triplett, NT, Hamilton, KC, Needle, AR, and van Werkhoven, H. The effect of different weight plate widths (bumper vs. standard) on the biomechanics of the bench press. J Strength Cond Res 38(4): e143-e149, 2024-Anecdotal evidence suggests that bumper plates impact lifts in powerlifting and weightlifting differently than standard cast iron plates, but whether biomechanical differences exist between lifts using bumper versus standard plates has not been investigated. Eleven resistance-trained subjects performed the bench press at 70, 80, and 90% of their 1 repetition maximum (1RM) while being blinded to whether they were lifting with bumper or standard plates. Motion data were captured by an 8-camera motion capture system, and electromyography (EMG) data were recorded for the anterior deltoid, pectoralis major, and triceps brachii. Repeated-measures analysis of variances showed a significant main weight effect for time under tension (p < 0.001), total work (p < 0.001), and muscle activity through EMG (across all muscles; p < 0.001) and a significant weight × joint interaction effect for average joint moment (p < 0.001) and peak joint moment (p < 0.001). However, there were no significant differences observed between the different weight plates for any of the measures. The main finding of the study suggests that there are no biomechanical differences between using bumper plates compared with standard plates during the bench press lift.

The Impact of Range of Motion on Applied Force Characteristics and Electromyographic Activity during Repeated Sets of Bench Press Exercise

This study examined the effects of range of motion (ROM) on applied force, power output and surface electromyographic (sEMG) responses during repeated sets of bench press exercise executed as fast as possible. Ten resistance trained men performed three sets to momentary failure with two-min rest intervals under three different ROM conditions: (a) full ROM (FULL), (b) TOP, at the top half of ROM, and (c) BOTTOM, at the bottom half of ROM. Mean and peak force were higher in TOP compared to FULL and BOTTOM (mean force: 817 ± 80 vs. 657 ± 98 vs. 623 ± 122 N, respectively, p < 0.001) with no differences between FULL and BOTTOM. During repeated sets, large decreases were found in peak (by 29.4 to 45.3%) and mean power (by 55.5 to 64.7%) from the first to the last repetitions. However, the decrease in mean force was only 2% (p < 0.01) and decreases in peak force ranged from 6.7 and 8.8% to zero, indicating the velocity loss was the main contributor to fatigue in power output. Although force and power output in set 3 were unchanged in BOTTOM, mean power output decreased significantly, suggesting that lower performance and fatigue may be related to the longer muscle length. Fatigue was accompanied by an increase in sEMG activity and a decrease in median frequency in all muscles, with triceps brachialis sEMG reflecting more the force and power differences among ROMs. In conclusion, fatigue depends on velocity rather than force loss during bench press exercise at different ROMs.

Will Music Give Me Power? Effects of Listening to Music during Active and Passive Rest Intervals on Power Output during Resistance Exercise

The study aimed to evaluate the impact of listening to preferred music during active/passive rest on power output and heart rate in barbell squats (BS) and bench presses (BP). Fifteen participants (13 males and 2 females), moderately resistance trained, were engaged in four randomized experimental sessions with varying rest intervals (active/passive) and music presence (listening or not). Each session involved three sets of three repetitions of BS and BP at a 50% one-repetition maximum. ANOVA showed a significant main effect of the set for BP relative mean and peak power output (p < 0.001; both). The post hoc comparisons indicated a significantly higher BP relative mean and peak power output in set_2 (p < 0.001; effect size [ES] = 0.12 and p < 0.001; ES = 0.10) and set_3 (p < 0.001; ES = 0.11 and p = 0.001; ES = 0.16) in comparison to set_1. Moreover, a main effect of the set indicating a decrease in BS relative peak power output across sets was observed (p = 0.024) with no significant differences between sets. A significantly higher mean heart rate during active rest in comparison to passive rest was observed (p = 0.032; ES = 0.69). The results revealed no significant effect of listening to music on relative power output and heart rate during BS and BP.

Impact of Starting Knee Flexion Angle on Muscle Activity and Performance during Plyometrics without Jumping

Most of the existing research has focused on jump plyometrics, where landing reaction forces must be dissipated among lower limb articulations. In contrast, the investigation of resisted plyometrics without jumping, devoid of such landing forces, remains relatively limited. This study aimed to (i) investigate the impact of resisted plyometrics without jumping at two knee flexion angles (60 and 90 degrees) on vastus muscle activity relative to limb dominance and (ii) assess strength, power, and work during the concentric-eccentric phases of these exercises. Thirty-one healthy participants underwent quantification of lower limb muscle amplitude, strength, power, and work during resisted plyometrics without jumping from both 60° and 90° knee flexion positions. After anthropometric evaluations, participants used a dynamometer with a load equal to 80% of body weight while wireless surface electromyography electrodes recorded data. Statistical analyses utilized paired t-tests or nonparametric equivalents and set significance at p ≤ 0.05. Results showed significantly higher muscle activity in the vastus medialis (VM) (dominant: 47.4%, p = 0.0008, rs = 0.90; nondominant: 54.8%, p = 0.047, rs = 0.88) and vastus lateralis (VL) (dominant: 46.9%, p = 0.0004, rs = 0.86; nondominant: 48.1%, p = 0.021, rs = 0.67) muscles when exercises started at 90° knee flexion, regardless of limb dominance. Substantial intermuscle differences occurred at both 60° (50.4%, p = 0.003, rs = 0.56) and 90° (54.8%, p = 0.005, rs = 0.62) knee flexion, favoring VM in the nondominant leg. Concentric and eccentric strength, power, and work metrics significantly increased when initiating exercises from a 90° position. In conclusion, commencing resisted plyometrics without jumping at a 90° knee flexion position increases VM and VL muscle activity, regardless of limb dominance. Furthermore, it enhances strength, power, and work, emphasizing the importance of knee flexion position customization for optimizing muscle engagement and functional performance.

Variability analysis of muscle activation symmetry to identify indicators of individual motor strategy: a case series on elite Paralympic powerlifters

Introduction

In Paralympic powerlifting competitions, movement execution symmetry is a technical requirement influenced by individual athlete characteristics and motor strategies. Identifying the elements associated with individual motor strategies can offer valuable insight for improving sport performance. Therefore, this case series study aimed to explore muscle activation symmetry and its intra- and inter-individual variability to determine the muscles mostly related to individual motor strategies in elite Paralympic powerlifters.

Methods

Bilateral electromyographic activation of the anterior deltoid (AD), pectoralis major (PM), latissimus dorsi (LD), triceps (TRI) and external oblique (EO) muscles were analysed in five elite Paralympic powerlifters while performing four sets of one-repetition maximum of Paralympic bench press. Muscle activation symmetry indexes (SI) were obtained and transformed to consider individual-independent evaluation. The coefficient of variation (CV), variance ratio (VR), and mean deviation (MD) were computed to assess inter- and intra-individual variability in electromyographic waveforms and SI.

Results

Both transformed and non-transformed SI indicated overall symmetric activation in DA, PM, TRI, and LD. Transformed SI revealed asymmetrical muscle activation of EO when grouping data (mean bilateral difference: 10%). Athletes exhibited low intra-individual SI variability in all analysed muscles (CV < 10%) and low inter-individual variability in DA, PM, LD, and TRI (CV < 10%; VR: 4%-11%; MD: 29%-43%). In contrast, higher inter-individual variability was observed in EO (CV: 23%; VR: 23%; MD: 72%-81%).

Conclusion

The highest variability and asymmetry in abdominal muscle activation among athletes emphasize the importance of personalized training approaches for targeting these muscles due to their role in individualizing motor strategies.

Evaluating the Asymmetry of Muscle Activation and Strength in Paralympic Powerlifting Athletes

BACKGROUND

Strength training is a complex task, as it requires a combination of many variables. In paralympic powerlifting (PP) asymmetries for the evaluation of activation, and static force indicators have been increasingly studied.

OBJECTIVE

To investigate the asymmetries in the strength and muscle activation indicators, before and after a training session of PP athletes.

METHODOLOGY

Twelve elite athletes from the PP participated in the study, and asymmetry was evaluated through surface electromyography (sEMG) and static strength indicators. Evaluations were made before and after a protocol of five series of five repetitions (5 × 5), with 80% of 1-Maximum Repetition (1RM).

RESULTS

In the pectoral muscles, there were differences in the non-dominant limbs between the before and after in the sEMG. There were differences in the pectoralis muscle in the non-dominant limb between moments before (110.75 ± 59.52%) and after (130.53 ± 98.48%, p < 0.001), and there was no difference in triceps activation. In the Maximum Isometric Strength (MIF), there was a difference in the non-dominant limb between before (710.36 ± 129.36) and after (620.27 ± 69.73; p < 0.030). There was a difference before in the dominant (626.89 ± 120.16; 95% CI 550.55-703.24) and non-dominant (710.36 ± 129.36; p = 0.011) limbs. There was no difference in time to MIF.

CONCLUSION

PP athletes showed small levels of asymmetry before and after training, and adaptation to training tends to promote fewer asymmetries.

Lower Fatigue in the Eccentric than the Concentric Phase of a Bench Press Set Executed with Maximum Velocity to Failure Against Both Heavy and Light Loads

We examined changes in barbell velocity and surface electromyographic activity (sEMG) during the concentric (CON) and eccentric (ECC) phases of a bench press set. Ten men executed a set to instant exhaustion as fast as possible, against a low (40% 1-RM) and a heavy load (80% 1-RM), one week apart. The reduction in mean barbell velocity was lower in the ECC compared with the CON phase for both loads (40%1-RM: ECC: -36 ± 21% vs. CON: -63 ± 14%, p < 0.001; 80%1-RM: ECC: -26 ± 15% vs. CON: -59 ± 9%, p < 0.001). Under both loading conditions, sEMG activity of the pectoralis major increased in the last compared to the first repetitions only in the CON phase (by 48.6% and 24.8%, p < 0.01, in the 40% and 80%1-RM, respectively). Similarly, triceps brachii sEMG increased by 15.7% (p = 0.02) and by 21.0% (p < 0.001) during the CON phase in the 40% and 80%1-RM conditions, respectively. However, during the ECC phase, sEMG remained unchanged in the last part of the set for both muscles and loads except for 80%1-RM in the pectoralis major muscle. It was concluded that fatigue measured by velocity loss was lower during the ECC than the CON phase of the bench press movement, when the exercise was performed with maximum velocity to failure, irrespective of the load. sEMG was lower in the ECC than the CON phase for all loads, and increased at the end of the set only during the CON phase, while it remained relatively unchanged in the ECC phase, with the exception of the pectoralis muscle when the load was heavier.

Left-Right Differential Erector Spinae Muscles Activation in Prone and Quadruped Positions

Left-right differential erector spinae (ES) muscle strengthening is required to correct ES muscle imbalances. The objective was to test the effect of 6 body positions on the differential activation of the ES muscles. In 14 able-bodied young women, using a surface electromyography system, the bilateral ES muscles activity at the third lumbar (ESL3) and the 10th (EST10) and 6th (EST6) thoracic vertebral levels was measured with the contralateral arm and leg lifted in the prone and quadruped conditions and with a single arm lifted in the quadruped position. Results showed that the activity of the ESL3 was symmetrical (P > .05) and significantly smaller than that of the thoracic ES muscles in all body positions (P < .01). The EST10 and EST6 were differentially activated in all tests (P < .001). Besides, the differential activation was higher in the contralateral-arm and -leg lift in the quadruped position than in the other positions. In conclusion, contralateral-arm and -leg lift and single-arm lift in the quadruped and prone positions are capable of differentially activating the ES muscles on one side more than the other side. Further studies are recommended to examine the effectiveness of these exercises on the correction of ES muscle imbalances in clinical populations.

A Comparison of Electromyographic Inter-Limb Asymmetry During a Standard Versus a Sling Shot Assisted Bench Press Exercise

The objective of this study was to compare peak surface electromyography (sEMG) activity of selected muscles along with inter-limb asymmetries between a control (CONT) and a Sling shot assisted (SS) bench press exercise. Ten resistance-trained males with at least three-year experience in resistance training (22.2 ± 1.9 years, 88.7 ± 11.2 kg, 179.5 ± 4.1 cm, bench press one-repetition maximum (1RM) = 127.3 ± 25.9 kg) performed the flat bench press exercise under two conditions at selected loads (85% and 100% of 1RM assessed without the SS). Peak sEMG amplitude of triceps brachii, pectoralis major, and anterior deltoid was recorded for the dominant and the non-dominant side of the body during each attempt. The comparison between the dominant and the non-dominant side was carried out using the limb symmetry index (LSI(%) = (2*(XR - XL)/(XR + XL))*100%) where XR = values of the right side and XL = values of the left side. There was a main effect of condition (p = 0.004; η² = 0.64) and the load (p = 0.004; η² = 0.63) for the triceps brachii LSI in parallel with a main effect of condition (p = 0.003; η² = 0.42) for the anterior deltoid LSI. Post hoc analysis for the main effect of condition showed significant differences in the LSI between the CONT and SS conditions for the triceps brachii (p = 0.003; 1.10% vs. -8.78%) as well as for the anterior deltoid muscles (p = 0.03; 12.91% vs. 9.23%). The results indicate that the assistance of the Sling shot significantly affects the sEMG activity pattern on both the dominant and non-dominant sides of the body while influencing inter-limb asymmetries.

The Effects of a Combined Pre- and Post-Operative Anterior Cruciate Ligament Reconstruction Rehabilitation Program on Lower Extremity Muscle Imbalance

This study examined whether the 5-week pre-operative progressive exercise rehabilitation program with weekly monitoring contributed to a significantly lower muscle activity imbalance in the treatment group, both before and immediately after anterior cruciate ligament reconstruction (ACLR), as well as during the next 5 weeks in comparison to the control group. Twelve professional soccer players took part in the study (from among the top three Polish levels of competition) (age: 26 ± 5 years, body mass: 73 ± 7 kg, stature: 180 ± 6 cm, training experience: 15 ± 4 years). The participants were randomly assigned to the treatment group (n = 6) or to the control group (n = 6). Both groups performed the same pre- and post-operative progressive exercise rehabilitation program, while the rehabilitation of the treatment group was extended by supplementary body-weight functional stabilization training. The three-way repeated-measures ANOVA revealed a statistically significant interaction for muscle × group × time (p < 0.0001; F = 24.897; η2 = 0.806). The post-hoc analysis for the interaction effect of muscle × group × time indicated a significantly higher muscle activity imbalance for every measured muscle in the control group at any time point than in the treatment group (from p = 0.036 to p < 0.0001). The muscle activity imbalance was significantly higher from the 1st to 4th weeks than in the last week before surgery for quadriceps (p < 0.016 for all) and hamstrings (p < 0.001). However, in the case of gluteal muscles’ activity imbalance, it was significantly higher at every time point of the post-operative phase than in the last week before surgery (p < 0.001). The results of this study showed that the 5-week pre-operative rehabilitation program with weekly monitoring influenced outcomes of the post-operative phase. Nevertheless, performing both pre- and post-ACLR rehabilitation significantly reduced the muscle activity imbalance of lower limbs, but in the case of the quadriceps muscles, not to a sufficient level.

Acute Effects of Different Intensities during Bench Press Exercise on the Mechanical Properties of Triceps Brachii Long Head

This study aimed to analyze acute changes in the muscle mechanical properties of the triceps brachii long head after bench press exercise performed at different external loads and with different intensities of effort along with power performance. Ten resistance-trained males (age: 27.7 ± 3.7 yr, body mass: 90.1 ± 17.1 kg, height: 184 ± 4 cm; experience in resistance training: 5.8 ± 2.6 yr, relative one-repetition maximum (1RM) in the bench press: 1.23 ± 0.22 kg/body mass) performed two different testing conditions in a randomized order. During the experimental session, participants performed four successive sets of two repetitions of the bench press exercise at: 50, 70, and 90% 1RM, respectively, followed by a set at 70% 1RM performed until failure, with a 4 min rest interval between each set. Immediately before and after each set, muscle mechanical properties of the dominant limb triceps brachii long head were assessed via a Myoton device. To determine fatigue, peak and average barbell velocity were measured at 70% 1RM and at 70% 1RM until failure (only first and second repetition). In the control condition, only muscle mechanical properties at the same time points after the warm-up were assessed. The intraclass correlation coefficients indicated “poor” to “excellent” reliability for decrement, relaxation time, and creep. Therefore, these variables were excluded from further analysis. Three-way ANOVAs (2 groups × 2 times × 4 loads) indicated a statistically significant group × time interaction for muscle tone (p = 0.008). Post hoc tests revealed a statistically significant increase in muscle tone after 70% 1RM (p = 0.034; ES = 0.32) and 90% 1RM (p = 0.011; ES = 0.56). No significant changes were found for stiffness. The t-tests indicated a significant decrease in peak (p = 0.001; ES = 1.02) and average barbell velocity (p = 0.008; ES = 0.8) during the first two repetitions of a set at 70% 1RM until failure in comparison to the set at 70% 1RM. The results indicate that low-volume, high-load resistance exercise immediately increases muscle tone but not stiffness. Despite no significant changes in the mechanical properties of the muscle being registered simultaneously with a decrease in barbell velocity, there was a trend of increased muscle tone. Therefore, further studies with larger samples are required to verify whether muscle tone could be a sensitive marker to detect acute muscle fatigue.

Effect of Inter-Repetition Rest vs. Traditional Resistance Training on the Upper Body Strength Rate of Force Development and Triceps Brachii Muscle Architecture

The purpose of the study was to examine the effect of seven-week inter-repetition rest vs. traditional resistance training on upper body maximum strength, the rate of force development and triceps brachii muscle architecture. Sixteen male participants were equally assigned into the inter-repetition rest and the traditional group. In both groups, training included the bench press exercise performed with 4 sets of 6 maximum repetitions, two training sessions per week. Twenty-second inter-repetition rest was employed for the inter-repetition rest group only. Measurements before and after the training period included maximum strength in the bench press, the isometric upper body rate of force development and peak force and triceps brachii muscle architecture. Maximum strength increased significantly in both groups (inter-repetition rest group: 21.5 ± 5.7% vs. traditional group: 13.5 ± 7.2%, p < 0.05), however, the maximum strength percentage increase was greater in the inter-repetition rest group compared to the traditional group (p = 0.027). Upper body isometric peak force increased only after inter-repetition rest training (10.7 ± 10.3%, p = 0.009). The rate of force development remained unchanged for both groups (p > 0.05), although percentage changes in time frames of 0-80 and 0-100 milliseconds were greater for the inter-repetition rest group compared to the traditional training group (p = 0.024 and p = 0.044, respectively). Triceps brachii thickness increased similarly for both groups (p < 0.05). These results suggest that inter-repetition rest may induce greater increases in maximum strength and the rate of force development compared to traditional training during the initial weeks of resistance training.

Evaluation of Lower Limb Muscle Electromyographic Activity during 400 m Indoor Sprinting among Elite Female Athletes: A Cross-Sectional Study

The purpose of this cross-sectional study was to analyze changes in normalized surface electromyography (sEMG) signals for the gastrocnemius medialis, biceps femoris, gluteus maximus, tibialis anterior, and vastus lateralis muscles occurring during a 400 m indoor sprint between subsequent curved sections of the track. Ten well-trained female sprinters (age: 21 ± 4 years; body mass: 47 ± 5 kg; body height: 161 ± 7 cm; 400 m personal best: 52.4 ± 1.1 s) performed an all-out 400 m indoor sprint. Normalized sEMG signals were recorded bilaterally from the selected lower limb muscles. The two-way ANOVA (curve × side) revealed no statistically significant interaction. However, the main effect analysis showed that normalized sEMG signals significantly increased in subsequent curves run for all the studied muscles: gastrocnemius medialis (p = 0.003), biceps femoris (p < 0.0001), gluteus maximus (p = 0.044), tibialis anterior (p = 0.001), and vastus lateralis (p = 0.023), but differences between limbs were significant only for the gastrocnemius medialis (p = 0.012). The results suggest that the normalized sEMG signals for the lower limb muscles increased in successive curves during the 400 m indoor sprint. Moreover, the gastrocnemius medialis of the inner leg is highly activated while running curves; therefore, it should be properly prepared for high demands, and attention should be paid to the possibility of the occurrence of a negative adaptation, such as asymmetries.

Shoulder Kinematics and Symmetry at Different Load Intensities during Bench Press Exercise

This study aimed to analyze between-shoulder kinematics symmetry at different load intensities considering full range of movement (ROM), mean and maximum velocities (VMEAN, VMAX), and accelerations (AMEAN, AMAX) of shoulders during phases 2 (characterized by positive acceleration and negative velocity, eccentric) and 3 (characterized by positive acceleration and velocity, concentric) of bench press exercise (BP); as well as to compare unilateral kinematics variables between the different load intensity intervals. Twenty-seven participants were evaluated during phases 2 and 3 of BP at different load intervals: interval 1 (55–75% 1-repetition maximum: 1RM), interval 2 (75–85% 1RM) and interval 3 (85–100% 1RM). Kinematics variables were determined using the Xsens MVN Link System. Results showed that full ROM was higher in left than right shoulder at all intensities (p = 0.008–0.035). VMEAN, VMAX, AMEAN, and AMAX were different in both shoulders for interval 3 during phase 2 and were lower as load intensity increased in both shoulders (p = 0.001–0.029). During phase 3, only VMAX on interval 2 was different between shoulders. Moreover, VMEAN, VMAX, AMEAN, and AMAX were greater during interval 1 compared with the others in both shoulders (p = 0.001–0.029). Therefore, there exists a kinematics asymmetry between both shoulders during phases 2 and 3 of bench press, although the acceleration was similar during both phases at all load intensities. Moreover, kinematic parameters differ between loads of 55–75% RM compared to 75–100% RM loads.

The Effects of Ischemia During Rest Intervals on Bar Velocity in the Bench Press Exercise With Different External Loads

The main aim of the present study was to evaluate the acute effects of ischemia used during rest periods on bar velocity changes during the bench press exercise at progressive loads, from 20 to 90% of 1RM. Ten healthy resistance trained men volunteered for the study (age = 26.3 ± 4.7 years; body mass = 89.8 ± 6.3 kg; bench press 1RM = 142.5 ± 16.9 kg; training experience = 7.8 ± 2.7 years). During the experimental sessions the subjects performed the bench press exercise under two different conditions, in a randomized and counterbalanced order: (a) ischemia condition, with ischemia applied before the first set and during every rest periods between sets, and (b) control condition where no ischemia was applied. During each experimental session eight sets of the bench press exercise were performed, against loads starting from 20 to 90% 1RM, increased progressively by 10% in each subsequent set. A 3-min rest interval between sets was used. For ischemia condition the cuffs was applied 3 min before the first set and during every rest period between sets. Ischemia was released during exercise. The cuff pressure was set to ∼80% of full arterial occlusion pressure. The two-way repeated measures ANOVA showed a statistically significant interaction effect for peak bar velocity (p = 0.04) and for mean bar velocity (p = 0.01). There was also a statistically significant main effect of condition for peak bar velocity (p < 0.01) but not for mean bar velocity (p = 0.25). The post hoc analysis for interaction showed significantly higher peak bar velocity for the ischemia condition compared to control at a load of 20% 1RM (p = 0.007) and at a load of 50% 1RM (p = 0.006). The results of the present study indicate that ischemia used before each set even for a brief duration of <3 min, has positive effects on peak bar velocity at light loads, but it is insufficient to induce such effect on higher loads.

Changes in EMG and movement velocity during a set to failure against different loads in the bench press exercise

This study examined changes in movement velocity and surface electromyographic (sEMG) activity of the pectoralis major (PM) and triceps brachii (TB) muscles during the bench press exercise to failure against different loads. Fourteen men performed a set to failure with maximum intended velocity, against low (40%-1 repetition maximum-RM), moderate (60%-1RM), and heavy loads (80%-1RM). Number of repetitions, volume load, mean and peak velocity, and total time increased with decreasing load (40% > 60% > 80%, p < 0.01). sEMG comparisons between different loads were performed by matching time under tension at the initial, middle, and last part of the set. sEMG was higher in the middle and last repetitions, compared with the initial, for all loads in both muscles (p < 0.001). sEMG activity of both muscles was higher in the 60% and 80%-1RM conditions compared with the 40%1-RM (p < 0.007). Also, sEMG of both muscles was similar for the 60%-1RM and 80%-1RM loads at the initial, middle, and last repetitions, with the exception of the last repetitions for the TB muscle. In contrast, sEMG integrated activity was higher for the 40% 1-RM and 60% 1-RM (p < 0.01) compared with the 80% 1-RM load. Mean velocity loss at exhaustion and drop in sEMG median frequency were greater in the 40% and 60%-1RM compared with the 80%-1RM condition (p < 0.05). It was concluded that performing a set to exhaustion with maximum intended velocity using a load of 60% 1-RM combines the characteristics of the high average sEMG activity of heavier loads, and the high total integrated sEMG observed at lighter loads.