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The aim of this study was to investigate muscle activation performance and maximum repetition test for the bench press, military press and the close-grip bench press exercises with the barbell and the Smith Machine. Twelve recreationally trained men (mean ± SD: 21.83 ± 4.5 yrs; 1.72 ± 0.1 cm; 80.3 ± 9.2 kg; 25.1 ± 2.96 kg·m-2; 17.3 ± 6.85%Fat) underwent a within-subject, randomized and counterbalanced repeated-measures to analyze the 10-RM strength and muscle activation in the bench press, military press, and the close-grip bench press. Electromyographic signals were collected for the pectoralis major, anterior deltoid, biceps brachii, and triceps brachii during 1 set of each exercise with the barbell and smith machine. No difference was observed in muscle activity for pectoralis major, anterior deltoid, biceps brachii, and triceps brachii when comparing the barbell and the Smith Machine (P>0.05). However, significant differences in 10-RM loads were observed between the barbell and the Smith Machine for the close-grip bench press and military press exercises. These finding should be important when considering the determination of training loads. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine which of two Olympic Weightlifting start positions would yield the more efficient movement pattern. We compared the traditional Olympic lifting starting position with an experimental alignment that has been proposed to reduce horizontal displacement of the barbell. It was hypothesized that the experimental alignment would produce a barbell path more closely approaching linear movement. Ten subjects completed a series of cleans and snatches under both alignment conditions. The experimental alignment resulted in significant reductions in horizontal displacement (~40.3 mm and ~31.9 mm for snatch and clean, respectively; P<0.05). The experimental alignment did not result in a significant difference in peak power (snatch, ~2.2%; clean, ~2.6%). The findings indicate that experimental alignment proposed in this study reduced barbell horizontal displacement during the snatch and clean. Further research is needed to determine if there is an influence of the starting position on power output during these lifts. [ABSTRACT FROM AUTHOR]

We investigated the time course of neuromuscular and hypertrophic adaptations associated with only four weeks of barbell squat and deadlift training. Forty-seven previously untrained women (mean±SD, age=21±3years) were randomly assigned to low volume training (n=15), moderate volume training (n=16), and control (n=16) groups. The low and moderate volume training groups performed two and four sets, respectively, of five repetitions per exercise, twice a week. Testing was performed weekly, and included dual X-ray absorptiometry and vastus lateralis and rectus femoris B-mode ultrasonography. Bipolar surface electromyographic (EMG) signals were detected from the vastus lateralis and biceps femoris during isometric maximal voluntary contractions of the leg extensors. Significant increases in lean mass for the combined gynoid and leg regions for the low (+0.68kg) and moderate volume (+0.47kg) groups were demonstrated within three weeks. Small-to-moderate effect sizes were shown for leg lean mass, vastus lateralis thickness and pennation angle, and peak torque, but EMG amplitude was unaffected. These findings demonstrated rapid muscular adaptations in response to only eight sessions of back squat and deadlift training in women despite the absence of changes in agonist-antagonist EMG amplitude. [ABSTRACT FROM AUTHOR]

The purpose of this study was to analysis muscles activation of lower back (erector spinal), L1 Para-spinal and L5 Para-spinal muscles while performing two types of squats, i.e. Barbell and Smith Machine Squats. Ten male weight lifters (21.6 ± 2.22 years) selected for the study, they performed one repetition of four different squats. The maximum voluntary contraction (MVC) was recorded with the help of biograph infinity software (EMG). Surface ElectroMyoGraphy (SEMG) was used for measuring muscle electrical activity that occurs during muscle contraction. The eight different squats were barbell front full squat (BFFS), barbell front half squat (BFHS), barbell back full squat (BBFS), barbell back half squat (BBHS), smith machine front full squat (SMFFS), smith machine front half squat (SMFHS), smith machine back full squat (SMBFS) and smith machine back half squat (SMBHS). Although no statistical differences were found in comparing the two types of squats, the muscles activation in smith machine squat is slightly higher in all the eight exercises. Hence, generates slightly more stress in the lower back muscles as compare to the barbell squat. [ABSTRACT FROM AUTHOR]

Girevoy sport (GS) has developed only recently in the West, resulting in a paucity of English scientific literature available. The aim was to document kettlebell trajectory of GS athletes performing the kettlebell snatch. Four elite GS athletes (age = 29-47 years, body mass = 68.3-108.1 kg, height 1.72-1.89 m) completed one set of 16 repetitions with a 32.1 kg kettlebell. Trajectory was captured with the VICON motion analysis system (250 Hz) and analysed with VICON Nexus (1.7.1). The kettlebell followed a 'C' shape trajectory in the sagittal plane. Mean peak velocity in the upwards phase was 4.03 ± 0.20 m s-1, compared to 3.70 ± 0.30 m s-1 during the downwards phase, and mean radial error across the sagittal and frontal planes was 0.022 ± 0.006 m. Low error in the movement suggests consistent trajectory is important to reduce extraneous movement and improve efficiency. While the kettlebell snatch and swing both require large anterior-posterior motion, the snatch requires the kettlebell to be held stationary overhead. Therefore, a different coaching application is required to that of a barbell snatch. [ABSTRACT FROM AUTHOR]

Previous investigations that have studied motor unit firing rates following strength training have been limited to small muscles, isometric training, or interventions involving exercise machines. We examined the effects of ten weeks of supervised barbell deadlift training on motor unit firing rates for the vastus lateralis and rectus femoris during a 50% maximum voluntary contraction (MVC) assessment. Twenty-four previously untrained men (mean age  = 24 years) were randomly assigned to training (n = 15) or control (n = 9) groups. Before and following the intervention, the subjects performed isometric testing of the right knee extensors while bipolar surface electromyographic signals were detected from the two muscles. The signals were decomposed into their constituent motor unit action potential trains, and motor units that demonstrated accuracy levels less than 92.0% were not considered for analysis. One thousand eight hundred ninety-two and 2,013 motor units were examined for the vastus lateralis and rectus femoris, respectively. Regression analyses were used to determine the linear slope coefficients (pulses per second [pps]/% MVC) and y-intercepts (pps) of the mean firing rate and firing rate at recruitment versus recruitment threshold relationships. Deadlift training significantly improved knee extensor MVC force (Cohen's d = .70), but did not influence force steadiness. Training had no influence on the slopes and y-intercepts for the mean firing rate and firing rate at recruitment versus recruitment threshold relationships. In agreement with previous cross-sectional comparisons and randomized control trials, our findings do not support the notion that strength training affects the submaximal control of motor units. [ABSTRACT FROM AUTHOR]

Introduction. The snatch technique is a discipline in Olympic weightlifting. The lifter has to raise the barbell from the platform directly above their head in one movement. While reviewing the literature on biomechanical analysis of the techniques of weightlifting, one can find positions on the analysis of parameters, such as barbell track, horizontal displacement, and angular positions of the joints in the individual phases of the lifter's movement. Many texts concern female and male lifters taking part in World or European Championships. The parameters of the best competitors are outlined - mostly those who finish in the top five places in competition. Mostly these are parameters regarding male lifters, and less frequently those of female lifters. In the literature review, an overlooked aspect is that of the definition of the diversity of indicators as regards the snatch technique practiced by female lifters depending on score. Material and methods. In the research, registered snatch attempts during the World Championship were used. Videos were used by judges to establish a maximum weight limit for female lifters. The attempts were registered by two cameras and were later digitally processed by the APAS 2000 system. Barbell parameters, maximum speed, average of the bar, and the parameters of the lifter-bar collocation (horizontal displacement of barbell weights and height elevation) were assessed. Results. The analysed attempts show the margin of error for measurement of the average speed of the barbell as 0.03 m/s. The difference in maximum speed of analysed attempts is 15%. The height of clearance of the first-placed female lifter's barbell was 12.7 cm, 30 cm for the last-placed. Conclusions. The sporting level of weightlifting by female lifters influences the analysed biomechanical indicators of the snatch. Those indicators, which are similar in the case of both the World Championship winner and the female lifter who came last, may be described as the average speeds of the barbell. The high sporting level of female lifters performing heavy lifting is characterized by the clearance of the barbell. [ABSTRACT FROM AUTHOR]

Background: The aim of the study was to assess the symmetry of flexion and extension movements in upper limbs in disabled powerlifters during bench press with different barbell loads. Material/Methods: 29 disabled athletes from the National Powerlifting Team were examined. Mean age was between 23.9 ± 6.1. Mean sport experience was 5.4 ± 3.6 years. Results: Both flexion and extension movement were performed symmetrically, which was indicated by an insignificant (p < 0.05) difference in the movement onset in the left and the right upper limb. Conclusions: Time differences in the movement onset and the achievement of maximal angular velocity were statistically insignificant in all trials (loads from 40% to 95% 1RM). During extension with loads over 60% 1RM differences in time of achieving maximal angular velocity were statistically significant or close. [ABSTRACT FROM AUTHOR]

The purpose was to examine the acute effect of pre-exercise static stretching on barbell power and velocity during the bench press exercise. Forty male high school athletes performed 1 repetition maximum (1 RM) testing and were divided into either a static stretching (SS), or a no stretching (NS) protocol. Subjects performed 1 set of 3 repetitions of the bench press with 50% 1 RM as a warm-up. SS then performed a series of stretching exercises for the involved muscles. After completing either the bench press warm-up or the stretching protocol, subjects executed one bench press repetition at 85% 1 RM. After 24 hours, the groups switched protocols. Concentric mean barbell power and velocity were measured during the 85% lift. Stretching resulted in significantly lower mean power (NS=366.6±115.7 W, SS=282.7±111.4W) and mean velocity (NS=0.413±0.103 m x s-1, SS=0.302±0.086 m ⋅ s-1) when compared to NS. Static stretching has an acute detrimental effect on muscular performance. [ABSTRACT FROM AUTHOR]

Copyright of Sport & Society / Sport si Societate is the property of Altius Academy Foundation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: The binding energy and optical properties of barbell excitons in GaAs–Ga1−x Al x As semiparabolic double quantum wells under intense laser fields are investigated. Calculations are performed within the effective mass and envelope-function approximations, including the conduction band nonparabolicity. The dependence of the binding energy, oscillator strength and exciton absorption spectrum on the laser field in symmetric and asymmetric quantum wells is studied by using a finite difference method. It is shown that the exciton radiative lifetime can be tuned to a large extent by a proper choice of the structure design (double well size, middle barrier position and its thickness) as well as by varying the laser field intensity. [Copyright &y& Elsevier]

The purpose of this article is to outline a series of teaching strategies to assist a beginning athlete to learn how to perform the power clean exercise. The power clean is a complex exercise that contains 5 event filled phases, these include: Starting position, First pull, Scoop, Second pull and the Catch. More specifically the Starting position can be characterized as the stage in which we start in the deadlift position, First pull as the barbell commences its upward trajectory, Scoop or transition which entails the rapid hip thrust, Second pull as the shoulders shrug in conjunction with triple extension of the lower extremities and the Catch as we adopt the squat position to complete the exercise. Adequate completion of the power clean can only be made possible by 1) establishing competence with the Romanian Deadlift, Upright Row and the Front Squat and 2) adhering to a simple and safe progression model. Learning and developing strength within the aforementioned lifts is a mandatory requirement before advancing to a progression model. A suggested progression model a beginning athlete could adhere to is the five following exercises: 1) jumping with an unloaded barbell, 2) performing the power clean from the mid - thigh, 3) performing it from the knee, 4) slightly inferior of the knee and 5) lastly from the platform. The first progression enables the athlete to understand the explosive component of the power clean; the second is to include the catch whilst performing it mid - thigh, third and fourth is to continue developing that form whilst completing it from the knee and below and the fifth is to finally complete the lift in its entirety from the platform. Follow the above to ensure satisfactory completion of the power clean. [ABSTRACT FROM AUTHOR]

The purpose of the study was to compare the kinematics of the barbell back squat between two footwear conditions and to evaluate the results with respect to recommendations put forth in the National Strength and Conditioning Association position statement for proper squat technique. Twenty-five subjects with 5 - 7 years of resistance training experience participated. Selected kinematics were measured during a 60% of 1RM barbell back squat in both barefoot and athletic shoe conditions. Paired-samples T tests were performed to compare the two footwear conditions. Significant differences were found in trunk (50.72±8.27 vs. 46.97±9.87), thigh (20.94±10.19 vs. 24.42±11.11), and shank segment angles (59.47±5.54 vs. 62.75±6.17), and knee joint angles (81.33±13.70 vs. 88.32±15.45) at the peak descent position. Based on the kinematic analysis of the barefoot squat, two kinematic advantages are countered by two disadvantages. Coaches and instructors should acknowledge these results with respect to a performer's capability, and be aware the advantages and disadvantages of barefoot squat from a kinematic perspective. [ABSTRACT FROM AUTHOR]

Recent studies have shown that individuals often imitate the behavior of others. In these studies, the observed and imitated behaviors were always identical. The present research goes one step further and disentangles the imitation of movements from their behavioral contexts. On the basis of theories that the perception of behavior refers to the same mental representations as the execution, we found that imitation is not confined to the same class of behaviors but rather to the same class of movements that may be involved in different behaviors. Four studies demonstrated that watching an athlete lifting a barbell leads to an increase in participants' drink intake when drinking involved a similar movement (lifting a cup) but not when drinking did not involve a lifting movement (drinking through a tube). The effects were stronger for individuals high in perspective taking (Study 1 ) and for situations in which the perspective was manipulated to be similar to the observed actor's (Study 2). These findings demonstrate the power of movements in imitation processes, suggesting that shared goal representation is not necessary for imitating others' movements. [ABSTRACT FROM AUTHOR]

With all the benefits of medical fitness, in patients with cardiovascular disease safety of exercises performed with weights require future studies. Given this consideration, this paper aims to show that exercises performed with a barbell-expander device request less cardiovascular system compared with those performed with barbell. The results show that in healthy subjects, exercises performed with barbell-expander device corresponding adjusted for risk of inducing ascent of blood pressure not increase systolic blood pressure as high that the exercises similar in execution maner and degree of request executed with barbell. However is present a moderate risk of increased heart rate. Some data suggests the potential of muscle growth as a result of exercise performed with this device. [ABSTRACT FROM AUTHOR]

International Journal of Exercise Science 5(3) : 183-195, 2012. The purpose of this study was to determine if either of the two deadlift starting positions would yield a more efficient movement than the other; (1) the traditional Olympic lifting and deadlift starting position with the barbell over the metatarsalphalangeal joint and under the acromioclavicular joint or (2) an experimental alignment with the bar over the navicular bone and under the most inferior and medial aspect of the scapular spine. This second starting position, developed as a teaching convention, differs from the historical alignment of toes-barbell-shoulder joint and is also proposed to reduce horizontal displacement of the bar thus minimizing the amount of work needed to complete the movement. It was hypothesized that the experimental alignment would produce a more efficient pulling movement compared to a traditional starting alignment. Efficiency was defined as a barbell path approaching linear movement, with larger horizontal displacements being considered less efficient than smaller displacements. Six intermediate level weightlifters, 23.8 ± 1.9 years of age, 164.7 ± 7.9 cm in height, 81.5 ± 31.9 kg in body mass, completed a series of deadlifts under both alignment conditions with 90% of their self-reported 1RM (169.0 ± 58.17 kg). Posterior horizontal barbell displacement was measured by videoanalysis. In the traditional alignment (metatarsalphalangeal-bar-acromioclavicular) displacement was 66.7 ± 12.9 mm and was 37.5 ± 13.7 mm in the experiment alignment (navicular-bar-scapular spine). The noted 43.8% reduction (29.2 mm) in horizontal displacement in the experimental alignment condition was statistically significant (p = 0.0001) and supports the hypothesis in regards to improved lifting efficiency. [ABSTRACT FROM AUTHOR]

Copyright of Sport Scientific & Practical Aspects is the property of Faculty of Physical Education & Sport, Tuzla University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)