Article

Comparison of Muscle Force Production Using the Smith Machine and Free Weights for Bench Press and Squat Exercises

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Abstract

The Smith machine (SM) (vertical motion of bar on fixed path; fixed-form exercise) and free weights (FWs) (free-form path) are commonly used strength training modes. Exercisers may need to alternate between types of equipment, depending on testing, training, rehabilitation, and/or the exercisers' goals. The purposes of this study were to compare muscle force production for SM and FWs using a 1 repetition maximum (1RM) for the parallel back squat and supine bench press exercises and to predict the 1RM for one mode from 1RM on the other mode. Men (n = 16) and women (n = 16) alternately completed 1RM testing for squat and bench press using SM and FWs. Analyses of variance (type of equipment x sex) and linear regression models were calculated. A significant difference was found between bench press and squat 1RMs for each mode of equipment for all participants. The squat 1RM was greater for the SM than the FWs; conversely, the bench 1RM was greater for FWs than the SM. When sex was considered, bench 1RM for FWs was greater than SM for men and women. The squat 1RM was greater for SM than FWs for women only. The 1RM on one mode of equipment was the best predictor of 1RM for the other mode. For both sexes, the equation SM bench 1RM (in kilograms) = -6.76 + 0.95 (FW bench 1RM) can be used. For women only, SM squat 1RM (in kilograms) = 28.3 + 0.73 (FW squat 1RM). These findings provide equations for converting between SM and FW equipment for training.

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... Literature has compared electromyography (EMG) and kinetic measures such as peak force (PF), power, and one-repetition maximum (1RM) between variations of the bench press (Cotterman, Darby, & Skelly, 2005;Goodman, Pearce, Nicholes, Gatt, & Fairweather, 2008;Koshida, Urabe, Miyashita, Iwai, & Kagimori, 2008;Marshall & Murphy, 2006;McCaw & Friday, 1994;Norwood, Anderson, Gaetz, & Twist, 2007;Saeterbakken & Fimland, 2013;Saeterbakken, Van Den Tillaar, & Fimland, 2011;Santana, Vera-Garcia, & McGill, 2007;Schick et al., 2010;Snarr & Esco, 2013;Uribe et al., 2010;Zemková et al., 2014). Previous investigations comparing the standard bench press to a Smith machine bench press have revealed increasing EMG activity of the antagonist muscle group, as well as trunk musculature, suggesting that additional muscles are recruited to increase stability (Saeterbakken et al., 2011). ...
... It was hypothesized that PF and EMG would be significantly higher in the foot down condition, indicating that the feet play a role in body stabilization and thus force production in the bench press. Force production and 1RM values during bench press variations have been investigated by several studies (Anderson & Behm, 2004;Cotterman et al., 2005;Koshida et al., 2008;Saeterbakken & Fimland, 2013;Saeterbakken et al., 2011;Santana et al., 2007;Stock, Beck, Defreitas, & Dillon, 2010;Zemková et al., 2014). Anderson and Behm (2004) reported a 59.6% decrease in force output of isometric bench press when performed on a Swiss ball. ...
... Differences in force and power output and 1RM have been observed with different variations of the bench press. Barbell bench press 1RM was higher than Smith machine 1RM in a previous investigation by Cotterman et al. (2005) with n = 32, suggesting that increased muscluture recruited for the less stable condition (barbell) enhanced 1RM. ...
Thesis
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The bench press is a multi-joint exercise commonly used to improve upper body strength. Previous investigations have analyzed kinetic and kinematic variables during different bench press variations. However, no known studies have examined the effect of foot position on force output and muscle activity. The purpose of this investigation was to examine the effects of 3 different foot placements on isometric bench press force and muscle activity. Twenty-one recreationally trained males (age: 22.57 ± 1.36 years; height: 176.95 ± 6.80 cm; body mass: 85.15 ± 12.54 kg) participated in this investigation. Self-reported one-repetition maximum (1RM) of at least body mass was used as inclusion criteria (self-reported absolute 1RM: 119.37 ± 26.44 kg; relative 1RM: 1.40 ± 0.22). Subjects performed the isometric bench press with a normal foot placement with both feet down on the ground (FD), both feet up on the edge of the bench (FU), and both feet resting on an adjacent bench parallel to the ground (FO) in a randomized order. After 2 familiarization trials with FD placement, subjects performed 3 maximum voluntary isometric contractions for approximately 3 s each. Peak force (PF) and average integrated electromyography (avgIEMG) values were recorded for the pectoralis major (PM), anterior deltoid (AD), triceps brachii (TB), vastus lateralis (VL), biceps femoris (BF), and gastrocnemius (G) muscles. PF output for FD, FU, and FO was 1134 ± 295 N, 1182 ± 247 N, and 1161 ± 249 N, respectively. The avgIEMG for the PM with the feet down, up, and out was 1.25 ± 0.50 mV, 1.19 ± 0.46 mV, and 1.20 ± 0.47 mV respectively. The avgIEMG for AD for feet down, up, and out was 3.20 ± 1.18 mV, 3.18 ± 1.23 mV, and 3.12 ± 1.18 mV, respectively. The avgIEMG for TB for feet down, up, and out was 2.26 ± 0.97 mV, 2.17 ± 0.93 mV, and 2.18 ± 0.89 mV, respectively. The avgIEMG for VL for feet up, down, and out was 0.26 ± 0.30 mV, 0.11 ± 0.01 mV, and 0.24 ± 0.25 mV, respectively. The avgIEMG for BF for feet down, up, and out was 0.21 ± 0.22 mV, 0.12 ± 0.05 mV, and 0.16 ± 0.10 mV, respectively. The avgIEMG for G for feet down, up, and out was 0.25 ± 0.14 mV, 0.23 ± 0.11 mV, and 0.20 ± 0.06 mV, respectively. A repeated measures general linear model returned no significant differences between conditions for force or muscle activity. Additionally, a Pearson correlation coefficient of 0.54 (sig. = 0.01) indicates a strong relationship between self-reported 1RM and isometric bench press in the foot down position. Different foot positions do not have a significant effect on peak force or muscle activity of upper and lower body muscles during the isometric bench press. In this investigation, the bar was attached to a rack which did not permit lateral, anterior, or posterior motion of the bar. In a free weight bench press where these types of motion are possible, the results may be different. Although force output and muscle activity were not different between isometric conditions, stability may be increased with both feet on the ground during a dynamic movement.
... The RT goals include: 1) Morphological transformation-increase in muscle mass, body composition change, body shaping, (Folland & Williams, 2007;Mitchell et al., 2013) 2) Muscle transformation -development of strength and power dimension (Häkkinen et al., 2002;Schoenfeld, Wilson, Lowery & Krieger, 2016) 3) Motor transformation -improvement of motor function and motor performance (Duchateau, Semmler & Enoka, 2006;Granacher et al., 2016). The most commonly used type of RT that cause the changes as mentioned above are free weights, and exercise machines (Cotterman, Darby & Skelly, 2005) and the usual question of a fitness trainer is whether they use one or the other, or combination of the two in their training programs. Training with free weights or with such a type of exercise is also called free form exercises, while exercises on the machines are called fixed form exercises (Baechle & Earle, 2000). ...
... It should also be emphasized that the SM is more secure for performing squats and other exercises (i.e., bench press, shoulder press, shrugs, upright row) because of the set of stands that makes it impossible for the bar to fall and injure the person performing the exercise. Consequently, the increase in safety and the multiple exercise options enhance the popularity of the SM as a resistance exercise mode (Cotterman et al., 2005). To provide some useful information and relevant scientific knowledge for strength trainers and all involved in sport, in this short overview, the squat on SM will be observed from a few possible contexts that characterize the exercise itself: position, load, training volume (repetitions and sets), recovery (resting time), power, muscular work, and one repetition maximum ...
... This kind of foot-placing results in the position which is behind the toes. Because of the need for less stability for performing the SM squat, there are changes in the production force and inclusion of muscle groups, which is resulting in increased weight lifted (Cotterman et al., 2005, Schwanbeck et al., 2009). Adding a vibration as possible efficient training stimulus might result in a tendency of superiority of squats, performed on a vibration platform in comparison to squats without vibrations with respect to maximal strength and explosive power, considering the external load is similar in recreationally resistance-trained men (Rønnestad, 2004). ...
Article
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During the past two decades, sports scientists, coaches, therapeutic specialists, and other professionals are using the Smith Machine exercise (SME) to improve lower limb muscle strength. By overviewing the literature, the position of the bar, load, training volume (repetitions and sets), recovery (resting time), power, muscular work, and one repetition maximum (1-RM) are characteristics describing the SME and presented as variables on which the resistance training (RT) program periodization is focused. Therefore, the aim of the present brief review is to clarify this crucial point and to simplify the SME approach for the strength and condition trainers as well as for all other scientist involved in sports or therapeutic work. This brief review offers an insight into several recommendations on the key points, firmly based on relevant literature.
... During the half-squat test, shoulders were in contact with the bar, and the starting knee angle was 180°. Foot spacing was set at approximately the same width as, or slightly wider than, shoulder width with toes pointing slightly outward [23]. To control the displacement path, the position that the individual needed to initiate the half-squat was determined using an electrogoniometer (TSD130B, Biopac Systems, Inc., CA). ...
... During the bench press test, the head, the shoulders and the hips were supported by the bench with 90°flexion of the knees, as suggested by Cotterman et al. [23]. The barbell was lowered in a continuous motion until the bar position was 1-2 cm above their intermammary line, and they were required to maintain this position for 1 s (velocity = 0 m/s). ...
... Press hand spacing was set at 165-200% of bisacromial width, which has been shown to provide the optimal strength values of all grip widths for the supine bench press [27]. Hand and foot spacing were recorded for replication in subsequent tests [23]. ...
Article
Bench press (i.e. arm-based) and half-squat (i.e. leg-based) are exercises commonly used to increase and evaluate muscular strength. In addition to differences in the location of the muscles that participate in each exercise, the total muscle mass required for the latter is larger than that involved in the former. The aim of this study is to analyze the effects of a maximal incremental strength test when performed by bench press and by half-squat on myocellular damage, oxidative damage and the inflammatory cytokine response. Ten male athletes were subjected to half-squat and bench press incremental strength tests. Blood samples were collected at rest, 15-minutes and 24 h post-test. Hydroperoxide and malondialdehyde concentrations were determined as lipid peroxidation markers. Lactate dehydrogenase (LDH) and creatine kinase isoenzyme MB (CK-MB) activities were determined as markers of muscle damage. α-Actin concentration was determined as a marker of sarcomeric damage. Serum interleukin (IL) 6, IL10, and tumor necrosis factor alpha (TNFα) were determined to assess the inflammatory response. LDH and CK-MB values were greater at 15 min and 24 h post bench press exercise (p < 0.05). No differences were found in lipid peroxidation or α-actin. Interestingly, IL10 values were greater in response to the press bench at 24 h post-test (p < 0.05). Our results suggest that, at equivalent workloads, an arm-based exercise induced higher anti-inflammatory effects and more severe muscle damage compared with a leg-based exercise.
... Literature has compared electromyography (EMG) and kinetic measures such as peak force (PF), power, and one-repetition maximum (1RM) between variations of the bench press (Cotterman, Darby, & Skelly, 2005;Goodman, Pearce, Nicholes, Gatt, & Fairweather, 2008;Koshida, Urabe, Miyashita, Iwai, & Kagimori, 2008;Marshall & Murphy, 2006;McCaw & Friday, 1994;Norwood, Anderson, Gaetz, & Twist, 2007;Saeterbakken & Fimland, 2013;Saeterbakken, Van Den Tillaar, & Fimland, 2011;Santana, Vera-Garcia, & McGill, 2007;Schick et al., 2010;Snarr & Esco, 2013;Uribe et al., 2010;Zemková et al., 2014). Previous investigations comparing the standard bench press to a Smith machine bench press have revealed increasing EMG activity of the antagonist muscle group, as well as trunk musculature, suggesting that additional muscles are recruited to increase stability (Saeterbakken et al., 2011). ...
... It was hypothesized that PF and EMG would be significantly higher in the foot down condition, indicating that the feet play a role in body stabilization and thus force production in the bench press. Force production and 1RM values during bench press variations have been investigated by several studies (Anderson & Behm, 2004;Cotterman et al., 2005;Koshida et al., 2008;Saeterbakken & Fimland, 2013;Saeterbakken et al., 2011;Santana et al., 2007;Stock, Beck, Defreitas, & Dillon, 2010;Zemková et al., 2014). Anderson and Behm (2004) reported a 59.6% decrease in force output of isometric bench press when performed on a Swiss ball. ...
... Differences in force and power output and 1RM have been observed with different variations of the bench press. Barbell bench press 1RM was higher than Smith machine 1RM in a previous investigation by Cotterman et al. (2005) with n = 32, suggesting that increased muscluture recruited for the less stable condition (barbell) enhanced 1RM. ...
... There are several studies on the extent of electromyography activity of the muscles during squat movements [5,[11][12][13][14]. Various studies have compared the level of muscle activity during the execution of the squat with the smith machine and with free weights [15][16][17]. According to different methodologies of these studies, different results have been reported regarding the amount of activity in the lower limb muscles [15][16][17]. ...
... Various studies have compared the level of muscle activity during the execution of the squat with the smith machine and with free weights [15][16][17]. According to different methodologies of these studies, different results have been reported regarding the amount of activity in the lower limb muscles [15][16][17]. Athletes use free weights more as tools for improving muscular strength and power. However, most beginners use these tools for their relative safety and ease of use of resistance training machines [18]. ...
Article
Many practitioners and trainers advise designing and executing resistance training programs that include free weights and machines for strength training. The aim of the present study was to compare the frequency spectrum of lower limb muscles during weight training with traditional and novel equipment. Fourteen healthy power lifters (age: 26±7 years) were participated in this study. A portable EMG system with six pairs of bipolar surface electrodes was used to record the electrical activity of the selected lower limb muscles at a sampling frequency of 1200 Hz. Participants had enough experience to perform Free Weights Squat, Smith Machine Squat, Smith Machine Squat with one leg and the Dead lift movements. Participants carried out each movement, 5 times at an intensity equal to 50% of one-repetition-maximum level. The results showed higher median frequency of the vastus lateralis muscle during free weight single-leg squat than those that in the free weight squat (p=0.001) and dead lift (p=0.000) movements in lifting phase. Also, the median frequency of vastus lateralis muscle in single-limb squat with smith machine was significantly higher than that in the dead lift movement (p=0.021). The median frequency spectrum of the gastrocnemius muscle in the free weight squat movement showed a significant increase during the downward phase relative to the free weight single-leg squat movement (p=0.039). In order to strengthen vastus lateralis muscle in athletes or individuals with weak vastus lateralis muscle, free weight single-leg squat movement is more effective than those that in the other movements.
... The effect of an unstable loads on force output has been less investigated and is less clear. Cotterman et al. (10) found that subjects had a larger 1RM on the barbell bench press compared with the Smith machine bench press by 16%. The authors hypothesized that the mechanical pattern dictated by the bar in a Smith machine may have put the upper extremity at a mechanical disadvantage at certain points in the range of motion, which would result in a more stable device producing less force. ...
... Second, the variations between the stable and unstable conditions were not large. We chose to compare dumbbells and barbells rather than a more stable load (such as a Smith machine) or less stable load (such as liquid-filled objects or hanging additional resistance from a chain) because of the large disparity between strength expressed using barbells vs. dumbbells (25), because the RM on a Smith machine may actually be less than using a barbell (10), and because these are arguably 2 of the most common forms of resistance exercise found in gyms and weight rooms. Other forms of resistance should be considered in subsequent investigations. ...
... These exercises provide the ability to easily adjust the external load and manipulate the rate of movement execution. In addition, these exercises more closely parallel movements experienced during sport, such as dynamic movements at increased velocities and the incorporation of movements in multiple planes (3). ...
... In addition, the weight machines are commonly used for those recovering from an injury such as during physical therapy. Weight machines provide rehabilitating patients the ability to perform resistance exercise while in a more controlled environment with less degrees of freedom of the movement pattern than those encountered during free weight exercises, whereas, for those actively participating in athletics, weight machines are generally not recommended because of the restricted range of motion, lack of muscular involvement, and uniplanar execution (3). ...
Article
Miller, RM, Freitas, EDS, Heishman, AD, Koziol, KJ, Galletti, BAR, Kaur, J, and Bemben, MG. Test-retest reliability between free weight and machine-based movement velocities. J Strength Cond Res XX(X): 000-000, 2018-Several devices are available to measure muscular power through velocity measurement, including the Tendo FitroDyne. The ability for such devices to produce consistent results is still questioned, and the reproducibility of measurement between free weight and machine exercise has yet to be examined. Therefore, the aim of this investigation was to determine the test-retest reliability for barbell velocity during the bench press (BP) and weight velocity during the 2 leg press (2LP) for loads corresponding to 20-80% of 1 repetition maximum (1RM). Forty recreationally active individuals (22.6 ± 2.5 years; 175.9 ± 10.8 cm; and 76.2 ± 13.2 kg) with a 1RM BP and 2LP of 66.8 ± 32.4 kg and 189.5 ± 49 kg, respectively, volunteered for this study. Subjects completed 1 familiarization visit preceding 3 testing visits, which encompassed 1RM determination and 2 days of velocity testing. Forty-eight hours after 1RM testing, the subjects performed 1 repetition at 20, 30, 40, 50, 60, 70, and 80% of their 1RM for each exercise in randomized order. Subjects returned to the laboratory 1 week later to perform the velocity assessment again in randomized order. Intraclass correlation coefficient (ICC2,1) and relative SEM for the BP and 2LP ranged from 0.56 to 0.98 (3-18.1%) and 0.78 to 0.98 (2.8-7.2%), respectively, and no mean differences were observed between trials. The results suggest high reliability for BP velocity between 30 and 60% 1RM and moderate reliability at 20, 70, and 80% 1RM, while the 2LP displayed high to excellent reliability from 20 to 80% 1RM. Cumulatively, machine-based exercise displayed greater reproducibility; however, additional machine exercises need to be examined to bolster this conclusion.
... In the contexts of athletic training and rehabilitation there is support for the use of the free barbell squat which may be considered more effective than the Smith squat 1-3 . The free squat is generally preferred by well-trained athletes because the requirement for balancing the barbell implicates large recruitment of trunk and lower limb musculature 12 . In agreement, Schwanbeck et al. 13 reported greater electromyographycal activity of the lower limb muscles when performing free squats compared to squatting in a Smith machine. ...
... The high bar and low bar squats were performed on a LifeFitness Hammer Strength 7° backward-inclined Smith machine. The backwardinclined type of Smith machine was selected due to being a ubiquitous system in many strength training venues 7,12,13,18 . The participants' 1RM was established two days prior to the test using the high bar free squat technique, since the participants stated that they were accustomed to establishing their 1 RM using the high bar free squat. ...
Article
Introduction: The squat is one of the most effective exercises in athletic training. However, there is a scarcity of research that reports the muscular and joint loads in the lumbar region incurred when performing the high bar and the low bar isometric squat modalities in a Smith machine. Therefore, this study aims to determine the muscle force of the lower back extensors, and the compressive (R c) and shear (R s) forces at the lumbo-sacral joint for the one repetition maximum (1RM) high bar and low bar isometric parallel-depth Smith squats.
... None of the participants had a history of knee injuries, fractures in lower limb, or lower limbs and trunk disorders and surgeries. A week before conducting the test, the experiment was explained to the subjects and the one repetition maximum test was measured [19] for both techniques, in all subjects. ...
... Feet were positioned shoulder width apart or slightly wider with toes pointed slightly outward during the squat [19] ( Figure 1A). The legs position was kept the same for each set of repetitions. ...
Article
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Purpose: A variation in squatting technique is using arms to actively push the bar up with the upper limbs which is common in bodybuilding. This study aimed to compare the Electromyography (EMG) activity of selected muscles during squat with and without upper limb assistance. Methods: This was a quasi-experimental study. Fifteen healthy male power lifters (using the convenience sampling method) participated in this study. Participants performed 2 sets of 5 repetitions while squatting 70% of their one-repetition maximum with and without upper limb assistance. Surface EMG signals were collected from 6 muscles using a wireless electromyography with a sampling frequency of 1200 Hz. The paired sample t test was used for statistical analyses at a significance level of P
... For example, the individual does not have to balance the weight himself during MT and can therefore use higher weights. In contrast, FWT is attributed to muscle activation close to natural movement, a higher range of motion, and better physiological responses (Cotterman et al., 2005;Gutierrez and Bahamonde, 2009;Shaner et al., 2014). Women also seem to achieve better adaptation performance in MT compared to FWT (Cotterman et al., 2005). ...
... In contrast, FWT is attributed to muscle activation close to natural movement, a higher range of motion, and better physiological responses (Cotterman et al., 2005;Gutierrez and Bahamonde, 2009;Shaner et al., 2014). Women also seem to achieve better adaptation performance in MT compared to FWT (Cotterman et al., 2005). Therefore, in order to test training-specific adaptation processes, the testing was specifically adapted to the training method of the respective group, i.e. changes in the force parameters in the FWT group were tested with free weights, while the MT group was tested on machines accordingly. ...
Article
Background: Resistance training is assumed to be a key player in counteracting the age-related decline of functional capacity as well as the incidence of falls in older adults. Functional training using free weights is presumed to mimic daily activities, but there is a lack of studies comparing free weight training with barbells and machine training in older adults. The purpose of this study was to evaluate the development of muscle strength for high resistance training in high functioning older people for machines as well as free-weights as well as testing the feasibility of free weight training for this target group. Methods: Thirty-two fitness trained women and men aged 60 to 86 years (mean: 66.9, SD: ±5.5) participated in this study. Machine exercisers (n = 16; chest press, leg press, upper row, biceps cable curls, triceps cable extension) vs. free weight exercisers (n = 16; squat, bench press, bent-over rowing, biceps curls, lying triceps press) participated twice à week for a total of 26 weeks. They trained the same five muscle groups for three sets with 10 to 12 repetitions at the 10-Repetition-Maximum, followed by 20 min of endurance training over six months. Three measurements (dynamic, isometric strength and endurance) were taken at the beginning, after 10 weeks and again after 26 weeks. Results: Repeated measures MANCOVA analysis revealed significant increases in the free weights training group (FWT) as well as in the machine training group (MT) over the period of 6 months. However, only for leg strength (113 vs. 44%) and triceps (89.0 vs. 28.3%) the free-weights group exhibited significant differences for the percentage increase over a period of 26 weeks compared to the machine group. A detraining period revealed the decline of the dynamic strength without training. The analysis of the follow-up questionnaire resulted in higher demands for safety, but also higher values for fun, motivation, future, and benefit for daily life for the FWT group compared to the MT group indicating an overall better evaluation of their training specific regime. Conclusion: Our results demonstrate that especially free-weight training has benefits in improving leg and triceps strength as well as in the subjective perception in older adults. Nevertheless, our results do not overall indicate that free-weight training is superior to machine training for increasing strength.
... In a study conducted by Cotterman et al (2005), bench press and squat exercises using free weight and Smith Machine were compared. Maximum strength for the group that performed bench press using Smith Machine was found to be 67.4±36 ...
... It is worth to mention that in this study the maximum obtained from free weight bench press exercises was higher than the one obtained with Smith machine, while it was the other way around for squat exercises. Cotterman et al. concluded that there was a significant difference between exercises done with free weight and those that are done using specialized equipment (Cotterman et al., 2005). ...
Thesis
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Objective: The aim of this study is to compare upper extremity strength gain between multi-push machines and free weight in individuals with a sedentary lifestyle that go to sports centers to workout. Based on the obtained results, machine efficiency and the best way to increase upper extremity strength are to be deduced. Method: 22 individuals between the ages of 18-53 (29.04±10.55 (Average±SD)), without any health problems and background in sports participated in our study. The participants were divided into two groups: Free Weight study group (FWG) and Smith Machine study group (SMG). Measured parameters of the participants were height, weight, elasticity, back strength, hand grip strength, lower extremity length, upper extremity length and muscle strength with the latter being done thrice per participant and the highest value being chosen as the relevant value. Data analysis was done using the SPSS 21.0 package program under which Two-Independent Samples T-Test and Two-Related Samples T-Test were used. Results: In this study, statistically significant differences were found between the pre-and post-testing values of the two groups (p<0.05). When two groups were compared with each other, no statistically significant differences were found (p>0.05). Nevertheless, the difference between pre-and post-testing values yielded a 1.25 average strength gain for SMG and 2.36 average strength gain for FWG. Conclusions: Workouts carried out with Smith Machine and free weights for a duration of 8 weeks have a positive effect on strength gain. Even though at a first glance the difference in strength gain between the two groups appears small, it will become significant enough after a long period of time.
... Dessa forma, o modelo alométrico é uma metodologia de pontuação que pode ser comparado com outros atletas de diferente massa corporal, ou seja, de categorias diferentes, no qual a maior pontuação indica maior força do corpo em relação à massa corporal (MC). Portanto, Brechue et al. [18], Vanderburgh et al. [24], Dooman et al. [32], Haff et al. [33], Cotterman et al. [34] os exercícios de supino (SP) utilizando modelo alométrico como exemplo a fórmula SP x MC-0,57 e o agachamento (AG) AG x MC-0,60, e concluíram que o modelo alométrico apresentou melhores resultados de comparação entre as diferentes categorias de peso em relação ao peso levantado e a massa corporal para competidores de powerlifting, principalmente nos exercícios agachamento e supino. ...
... Contudo, segundo Breachue & Abe [18], Cotterman et al. [34], Moore et al. [36] a capacidade de suportar maiores cargas podem estar relacionadas com a estatura e massa corporal, e principalmente com massa livre de gordura. Dessa forma, a capacidade dos atletas de powerlifting de aumentar a quantidade de cargas absolutas levantadas em competição apresenta afinidade a massa corporal, na qual, o aumento da força pode ser explicada pela redução de massa livre de gordura. ...
Article
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Introdução: A composição corporal e os indicadores morfofuncionais são importantes aspectos no desempenho de atletas de powerlifting. Portanto, buscar informações sobre a influência da composição corporal no desempenho esportivo de atletas pode trazer informações que poderiam explicar os resultados em competições e progressão nas cargas de treinamento. Objetivo: Realizar uma revisão sistemática sobre as características morfológicas de atletas e praticantes de powerlifting. Métodos: para a realização do presente estudo,foram utilizadas as bases de dados (Scielo,Ebsco,PubMed e Portal Capes Brasil). Os descritores powerlifting, anthropometric, training foram utilizados no intervalo temporal de análise entre 2000 a 2013. Resultados: Foram selecionados 112 artigos,sendo que 15 artigos permaneceram na presente revisão por atender os critérios de inclusão, especialmente por terem analisado o perfil morfológico de atletas e praticantes de powerlifting. Os resultados principais demonstraram que a média de idade foi de 33 ± 2 anos, tempo de prática de 10 ± 2 anos e média de 39 ± 5 sujeitos avaliados por estudo. Conclusão: Dados permitiram concluir que os atletas e praticantes de powerlifting são predominantemente mesomorfos,com grandes diâmetros ósseos, sendo que as diferenças entre massa muscular e adiposidade mostraram um discreto aumento da massa livre de gordura ao longo de um período de treinamento.Palavras-chave: powerlifting, training, anthropometry.
... The findings are therefore in conflict with the principle of training specificity but are supported by most previous findings comparing resistance exercises with major differences in stability requirements (i.e., using unstable surfaces) (5,7,8,34,38). However, fewer studies have examined exercises using the Smith machine and free weights (15,35,37,38). In bench presses, similar and greater 1RM loads have been observed (35,37), whereas greater loads have been observed using the Smith machine than free weights in squats (15,38). ...
... However, fewer studies have examined exercises using the Smith machine and free weights (15,35,37,38). In bench presses, similar and greater 1RM loads have been observed (35,37), whereas greater loads have been observed using the Smith machine than free weights in squats (15,38). Different resistance training experience and familiarization with exercises may explain the findings. ...
Article
Saeterbakken, AH, Stien, N, Pedersen, H, and Andersen, V. Core muscle activation in three lower extremity with different stability requirements. J Strength Cond Res XX(X): 000-000, 2019-The aim of the study was to compare core muscle surface electromyography (sEMG) during 3-repetition maximum (3RM) and the sEMG amplitude in the turnover from the descending to ascending phase in leg press, free-weight squats, and squats using the Smith machine. Nineteen women with 4.5 (±2.0) years of resistance training were recruited. After one familiarization session, the subjects performed 3RM in randomized order measuring electromyographic activity in the rectus abdominis, external oblique, and erector spinae. The exercises with the lowest stability requirements (leg press) demonstrated 17-59% and 17-42% lower core muscle sEMG amplitude than free weights and the Smith machine, respectively. No statistically significant differences were observed between the Smith machine and free weights. No statistically significant differences in turnover sEMG amplitude in the rectus abdominis between the exercises was observed, but lower sEMG amplitude was observed in external oblique and erector spinae in leg press compared with the other exercises. The 3RM loads in leg press were 54 and 47% greater than squats using the Smith machine and free weights, with 5% greater loads with the Smith machine than with free weights. In conclusion, lower mean and turnover core muscle sEMG amplitude were observed with the leg press but greater 3RM loads compared with squats with the Smith machine and free weights. The authors recommend that resistance-trained individuals use squats to include the core muscles in the kinetic chain, but there is no evidence that greater stability requirements (free weights instead of the Smith machine) will result in greater core muscle sEMG amplitude.
... In this study it was verified better performance in the second situation, with values up to 18% higher for impulse produced in the first 0.37s of concentric action. This may be explained by the fact that, during an eccentric action, elastic components stretch in the musculoskeletal system, generating an accumulation of elastic potential energy that will be used in the beginning of the concentric action; this enables higher motion speeds in the beginning of the concentric action and generates greater strength responses compared to isolated concentric action 19,20 . Thus, the weight corresponding to 60% of 1RM was determined in this condition. ...
... Therefore, repetition duration presented itself as another mediating variable for results. In self-paced durations, there may be changes in speed and acceleration as a way to optimize performance at different ROMs -for instance, the end of eccentric action in squat, and the second half of concentric action in leg curl; in the first case, to reduce the transition time and optimize the SSC utilization, and, in the second case, to overcome the ROM in which the sticking point manifests 20 . These changes in acceleration may also happen in moments of greater fatigue with the aim of not interrupting the task. ...
Article
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The objective of this study was to investigate the effect of exercise order of two exercises involving the participation of common musculature (smith machine back squat and leg curl, on the NMR, in two repetition durations. Sixteen trained male volunteers participated in this study. The protocols were performed in two exercise orders and repetition durations (self paced and 4s) in which volunteers realized their NMR in each exercise over two sets, at an intensity of 60% of 1RM, with 90 seconds between sets and 180 seconds between exercises. The ANOVA whit repeated measures were performed for comparison of the NMR and Bonferroni post hoc was applied when necessary. Regarding the self paced repetition duration, both exercises presented a higher NMR when performed as the first exercise than when performed as second. However, there was neither interaction nor main effect of the factors analyzed for the repetition duration of 4s. Therefore, it is concluded that the repetition duration is a variable capable of modifying the results found by the different orders.
... 40 Unlike Smith machine modalities, the backsquat can involve greater horizontal movement of the barbell which is known to affect velocity measures calculated by LPTs. 41 Therefore, the findings from Smith machine investigations of the Vitruve should not be used to infer the LPTs reliability during free-weight exercise. While a plethora of studies have investigated the reliability of LPTs during lower body free-weight exercises, [42][43][44] the reliability of the Vitruve during backsquat exercise is not known. ...
... 43,44,54,60,61 Although the Vitruve's reduced reliability at 90% 1-RM was consistent with other analyses. 38,42,43,49,50 This has been attributed to horizontal variations in the barbell path during the free-weight squat 41 and the use of the SSC. 62,63 This is why previous investigations have used Smith machine An unexpected finding was the detection of significant differences for MV and PV between trials at 60% 1-RM. ...
Article
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The purpose of this study was to examine the reliability of load-velocity profiles (LVPs) and validity of 1-repetition maximum (1-RM) prediction methods in the back-squat using the novel Vitruve linear position transducer (LPT). Twenty-five men completed a back-squat 1-RM assessment followed by 2 LVP trials using five incremental loads (20%-40%-60%-80%-90% 1-RM). Mean propulsive velocity (MPV), mean velocity (MV) and peak velocity (PV) were measured via a (LPT). Linear and polynomial regression models were applied to the data. The reliability and validity criteria were defined a priori as intraclass correlation coefficient (ICC) or Pearson correlation coefficient (r). 0.70, coefficient of variation (CV) 410%, and effect size (ES) < 0.60. Bland-Altman analysis and heteroscedasticity of errors (r 2) were also assessed. The main findings indicated MPV, MV and PV were reliable across 20%-90% 1-RM (CV < 8.8%). The secondary findings inferred all prediction models had acceptable reliability (CV < 8.0%). While the MPV linear and MV linear models demonstrated the best estimation of 1-RM (CV < 5.9%), all prediction models displayed unacceptable validity and a tendency to overestimate or underestimate 1-RM. Mean systematic bias (27.29 to 2.83 kg) was detected for all prediction models, along with little to no heteroscedasticity of errors for linear (r 2 < 0.04) and polynomial models (r 2 < 0.08). Furthermore, all 1-RM estimations were significantly different from each other (p < 0.03). Concludingly, MPV, MV and PV can provide reliable LVPs and repeatable 1-RM predictions. However, prediction methods may not be sensitive enough to replace direct assessment of 1-RM. Polynomial regression is not suitable for 1-RM prediction.
... Research has highlighted key kinematic differences between Smith machine and free-weight variations of the same exercise, including an increased joint range of motion associated with free-weight exercise (Gutierrez & Rafael, 2009). Additionally, as bar path is not fixed in free-weight exercise the way it is when using a Smith machine, there may be increased sagittal plane movement (Cotterman et al., 2005). These factors likely lead to increased variation in exercise technique and subsequently variation in repetition velocity in free-weight exercise compared to Smith machine exercise. ...
... In fact, it is often proposed that high-level athletic populations may employ these strategies to determine frequent changes in 1RM, without the need for a time consuming and fatiguing, direct assessment. However, the evidence presented in the current study highlights predictions may be more effective for highly controlled machine exercise (Picerno et al., 2016), as compared with the free-weight compound exercises typically used by this population (Cotterman et al., 2005). ...
Article
This study aimed to determine differences in the validity and reliability of 1RM predictions made using load-velocity relationships in Smith machine and free-weight exercise. Twenty well-trained males attended six sessions, comprising the Smith machine and free-weight squat, bench press, prone row and overhead press. Load-velocity relationship-based 1RM predictions were performed using minimal velocity threshold (1RMMVT), load at zero velocity (1RMLD0) and force-velocity (1RMFV) methods, with 5- or 7-loads. Measured 1RM did not differ from 1RMMVT or 1RMLD0 for any of the Smith machine exercises, while it was higher than 1RMFV for all exercises except the prone row. For the free-weight variations all 1RM predictions differed from measured 1RM for the squat and overhead press, while measured and predicted 1RM did not differ in the bench press and prone row. No differences were observed between 7-and 5-load predictions. 1RMMVT was the most reliable and valid each of the methods. Smith machine exercises resulted in more reliable predictions than free weight exercises. 1RMMVT provides valid and reliable predictions for the Smith machine, squat, bench press, prone row and overhead press and free-weight bench press and prone row. Practitioners must be aware of the poor validity of free-weight squat and overhead press predictions.
... Birbirinden bağımsız olarak, serbest ağırlık ve makine ağırlık uygulamalarının kuvvet performansı üzerine etkisiyle ilgili çok sayıda çalışma olmasına karşın 2 uygulamanın kıyaslandığı az sayıda çalışma bulunmaktadır. [7][8][9][10] Bu çalışmalarda da genellikle farklı hareketlerde serbest ağırlık ile makine uygulamasındaki kas aktivasyonu, 1-TM kuvvet performansı karşılaştırmaları yapılmıştır. ...
... Cotterman ve ark.nın yaptığı çalışmada squat hareketinde, hem kadınlar hem de erkekler SA uygulamasına göre M'de daha yüksek maksimal kuvvet performansı sergilenirken, bench press hareketinde ise squat hareketinden farklı olarak, SA uygulamasında daha yüksek 1-TM performansı tespit edilmiştir. 7 Bench press hareketiyle ilgili olarak benzer bir sonuç, Schick ve ark.nın M ile SA uygulamalarındaki karşılaştırmada elde edilmiştir. ...
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Smith Ağırlık Makinesi ve Serbest Ağırlık Karşılaştırması: Farklı Yüklerin ve Antrenman Tecrübesinin Set Tekrarları Üzerine Etkisi https://www.turkiyeklinikleri.com/article/en-smith-agirlik-makinesi-ve-serbest-agirlik-karsilastirmasi-farkli-yuklerin-ve-antrenman-tecrubesinin-set-tekrarlari-uzerine-etkisi-90396.html
... These findings were consistent with Saetterbakken et al. 7 who observed a higher 1RM load when the bench press was performed with a barbell versus dumbbell and Smith machine. Cotterman et al. 16 found that the Smith machine, often characterized by one degree of freedom, maintains a standard and limited range of motion, reducing recruitment of primary muscles, and consequently presenting a lower 10RM load. For the DBP, the lower 10RM load might be associated to the greater stability requirements that decreases the net torque and the ability to lift the weight. ...
... One of the most commonly used exercises to improve and evaluate upper body strength is the bench press (Farias et al., 2017;van den Tillaar & Ettema, 2009;Welsch, Bird, & Mayhew, 2005). Bench press exercises can be carried out in either free form or fixed form (Cotterman, Darby, & Skelly, 2005). The choice of one exercise mode in relation to the other depends on the population and training purpose. ...
Article
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Performing the bench-press (BP) exercise in a weight stack machine (WSM) is a common practice. However, no previous studies have analysed the load-velocity relationship in this BP variant. The purpose of this study was 1) to investigate the load-velocity relationship during BP exercise using a WSM; and 2) to compare the load-velocity relationship in this exercise in two conditions: WSM vs. Smith machine (SM). Twenty-six young men performed a BP progressive loading test to determine their one-repetition maximum and load-velocity relationship using a WSM. Additionally, 19 participants performed two progressive loading tests (WSM and SM). A high relationship was found between the relative load (%1RM) and mean propulsive velocity (MPV) (R2 = 0.97; SEE = 0.07 m/s) in the WSM. Moreover, significant differences were observed (p <.05) in the MPV values attained in every %1RM in WSM and SM from 30 to 75% 1RM. The close relationship between the MPV values and the %1RM in BP exercise using a WSM enables coaches to use the MPV to accurately monitor their athletes on a daily basis. The differences observed between WSM and SM in the %1RM and their respective MPVs indicate that different equations must be used for each exercise mode.
... While a high number of studies have analysed muscle activity patterns during bench press exercises [7][8][9][10][11][12][13], relatively little research has been done on joint kinematics and kinetics of the upper limbs for both bench press and cable pulley exercises. The authors of [14] investigated the effects of exercise intensity on trunk muscle activity during pulleybased shoulder exercises on an unstable support surface. ...
Article
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Injuries to the shoulder are very common in sports that involve overhead arm or throwing movements. Strength training of the chest muscles has the potential to protect the shoulder from injury. Kinematic and kinetic data were acquired in 20 healthy subjects (age: 24.9 ± 2.7 years) using motion capture, force plates for the bench press exercises and load cells in the cable for the cable pulley exercises with 15% and 30% of body weight (BW). Joint ranges of motion (RoM) and joint moments at the shoulder, elbow and wrist were derived using an inverse dynamics approach. The maximum absolute moments at the shoulder joint were significantly larger for the cable pulley exercises than for the bench press exercises. The cable cross-over exercise resulted in substantially different joint angles and loading patterns compared to most other exercises, with higher fluctuations during the exercise cycle. The present results indicate that a combination of bench press and cable pulley exercises are best to train the full RoM and, thus, intra-muscular coordination across the upper limbs. Care has to be taken when performing cable cross-over exercises to ensure proper stabilisation of the joints during exercise execution and avoid joint overloading.
... 15 Therefore, the back squat in the machine Smith was used in this study, because although differences are well established between free weight and Smith machine resistance exercise modalities, instrument positioning and horizontal excursions from the vertical and bar rotational movements appear to be the major concerns for comparative accuracy between the different measurement systems. 17 Therefore, this study determined the reliability of the Wimu (accelerometer) to measure the mean velocity during resistance exercises with two intensities, 40% and 80% 1 repetition maximum (1RM), commonly used in resistance training. This study also evaluated the validity of the Wimu (accelerometer), compared to the linear encoder when the Wimu was clipped to the bar of a Smith machine to measure mean velocity during the back squat exercise in the concentric and eccentric phases. ...
Article
This study had two main goals. The first was to determine the reliability of the Wimu® system (accelerometer) for mean velocity measurements during resistance exercises at 40% and 80% 1 repetition maximum (1RM). The second was to compare the results for the Wimu system to a linear encoder (gold standard) for mean velocity measurements when clipped to the bar during back squat exercises using the Smith machine. In all, 23 trained men (aged 22.3 ± 3.2 years) participated in this study. At maximum velocity in the concentric phase, they performed 10 repetitions with 40% 1RM and eight repetitions with 80% 1RM while using the Wimu system and T-Force linear encoder simultaneously to record data. Reliability was analysed using intraclass correlation, standard error of measurement and coefficient of variation. The validity was assessed using R², intraclass correlation and Bland-Altman plots. The differences in test–retest reliability of both systems and systematic biases were non-significant (p = 0.08–0.85) and very close to 0. The random errors averaged ±0.010 m/s. All the calculated coefficient of variations were less than 5% and all measurements had high intraclass correlations (mean: 0.936). Least-square linear regression and intraclass correlations for validity were very close to 1. Significant systematic biases were observed between the linear encoder and the Wimu system (p < 0.001), although the effect sizes were small (0.21–0.44) and standard error of the estimate in concentric and eccentric phases at both intensities was less than 0.030. In conclusion, the findings of this study suggest that the Wimu system is a reliable and valid tool for the assessment of mean velocity during the back squat exercise using the Smith machine. These findings could help coaches and sport researchers evaluate athletes performing resistance exercises similar to squats with a reliable, valid and portable tool.
... However, it is important to note that these results should be regarded with caution, given that the exercises were performed on a Smith machine and in a concentric-only manner. Consequently, these findings cannot be generalized to movements that are not restricting the barbell pathway or taking advantage of the stretch-shortening cycle, given that free-weight exercises likely change the kinetic and kinematic characteristics of the movement (10,35). More recently, Loturco et al. (25) investigated the accuracy in predicting the 1RM in the free-weight bench press and reported absolute differences of ,5% between predicted and actual 1RM. ...
Article
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The aim of the present study was to verify the reliability and validity of using submaximal loads from the load-velocity relationship to predict the actual 1RM in the deadlift. Data from 11 resistance-trained athletes were analyzed performing three 1RM assessments separated by at least three days. Reliability was assessed by comparing predicted 1RMs of session 2 and 3, while for validity purposes predicted 1RMs of session 3 were compared to actual 1RMs of session 2. Mean-concentric velocity at 1RM (v@1RM) was entered in individualized linear-regression equations, derived from the load-velocity relationship for three (20-60, 40-80% and 60-90% of 1RM), four (20-80% and 40-90% of 1RM), and five (20-90% of 1RM) incremental loads to predict 1RMs. There were trivial changes for all predicted 1RMs between sessions with 20-90% of 1RM being the most reliable model. Similarly, the actual 1RM was very stable (ES = 0.04, 90% CL [-0.03; 0.12], TE = 3.4 kg [2.5; 5.4], ICC = 0.99 [0.96; 0.996], CV = 1.9% [1.4; 3.0]), while the v@1RM was unreliable between trials (ES = -0.30, 90% CL [-0.78; 0.17], TE = 0.029 m.s-1 [0.022; 0.047], ICC = 0.63 [0.19; 0.86], CV = 15.7% [11.7; 26.1]). However, predicted 1RMs computed from all submaximal load ranges substantially overestimated the actual 1RM with considerable differences between athletes. Although 1RM predictions showed high reliability, they all overestimated the actual 1RM, which was stable between sessions. Therefore, it is not recommended to apply the prediction models used in this study to compute daily 1RMs.
... Also, the semi-squat standing in off vibration system should have any impact on the muscle strength. The previous researches indicate that the keeping the squat position would increase the strength of lower extremities' muscles (54)(55)(56)(57)(58)(59) .Furthermore, no significant differences 8 were shown in the vastus medialis RMS value in SLR position among the groups, but there was a significant rate in progress of the above-mentioned variable in WBVT group (33. 62%) compared two other groups (placebo:5.73% and CT: 6.91%). ...
Article
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Background: Whole-Body Vibration Training (WBVT) is a novel neuromuscular training method that has been recently developed as a rehabilitation tool. The purpose of this study was to determine whether WBVT is effective on electromyographic activity of the muscles of the lower limbs in patients with knee osteoarthritis. Methods: The study was designed as a single blinded randomized clinical trial (IRCT201601171637N5), 45 patients with knee osteoarthritis were randomly assigned to three groups; WBVT (n = 15) receiving 12 sessions vibration therapy, control group (n =15) doing two exercise in the home and placebo (n =15) doing exercise like WBVT group on-off vibration system. Electromyographic activities of vastus lateralis and vastus medialis, semitendinosus, gastrocnemius and soleus were evaluated pre and post intervention. The pairedsamples t-test and ANOVA were applied respectively to determine the differences in each group and among the groups (P≤0.05). Results: The RMS value of vastus medialis in semi squat position in placebo group (p=0.024), vastus lateralis in SLR position in WBVT group (p=0.037), soleus in knee flexion in WBVT group (p=0.018), semitendinosus in knee flexion in WBVT group (p=0.007) and RMS response of Semitendinosus in ankle plantar flexion in control group (p=0.047) were revealed significant differences between the pre- and post- intervention. The ANOVA test confirmed the significant differences between the studied groups according to the EMG activity of vastus medialis in semi squat position (p=0.045), semitendinosus in semi squat position (p=0.046) and in plantar flexion position (p=0.015) and also soleus in plantar flexion position (p=0.003). Conclusions: The findings of this study showed the beneficial effects of WBVT in the improvement of the muscles RMS values in the patients with knee OA especially muscles' progression rates in a four-week period.
... A potential limitation of current research is the emphasis of methodology using machine-based exercises. Importantly, the individuals who are most likely to undertake velocitybased 1RM predictions are high-performance athletes training in a professional setting; although these cohorts do make use of machine-based exercises, the majority of their training is typically comprised free-weight exercises (10). Therefore, the aim of this study is to examine the reliability and validity of all currently available velocity-based 1RM prediction methods using free-weight, rather than machine-based, exercise. ...
Article
The purpose of this study was to investigate the reliability and validity of predicting 1-repetition maximum (1RM) in trained individuals using a load-velocity relationship. Twenty strength-trained men (age: 24.3±2.9 years, height: 180.1±5.9 cm, body mass: 84.2±10.5 kg) were recruited and visited the laboratory on three occasions. The load-velocity relationship was developed using the mean concentric velocity of repetitions performed at loads between 20% and 90% 1RM. Predicted 1RM was calculated using 3 different methods discussed in existing research; minimal velocity threshold 1RM (1RMMVT), load at zero velocity 1RM (1RMLD0) and force-velocity 1RM methods (1RMFV). The reliability of 1RM predictions was examined using intraclass correlation coefficient (ICC) and coefficient of variation (CV). 1RMMVT demonstrated the highest reliability (ICC=0.92-0.96, CV=3.6-5.0%), followed by 1RMLD0 (ICC=0.78-0.82, CV=8.2-8.6%) and 1RMFV (ICC=-0.28-0.00, CV= N/A). Both 1RMMVT and 1RMLD0 were very strongly correlated with measured 1RM (r=0.91-0.95). The only method which was not significantly different to measured 1RM was the 1RMLD0 method. However, when analyzed on an individual basis (using Bland-Altman plots), all methods exhibited a high degree of variability. Overall, the results suggest that the 1RMMVT and 1RMLD0 predicted 1RM values could be used to monitor strength progress in trained individuals without the need for maximal testing. However, given the significant differences between 1RMMVT and measured 1RM, and the high variability associated with individual predictions performed using each method, they cannot be used interchangeably; therefore, it is recommended that predicted 1RM is not used to prescribe training loads as has been previously suggested.
... Considering the studies conducted in this field in the literature, Cotterman et al. (2005) determined 34.2 ± 8.3 kg for bench press women and 86.6 ± 13.8 kg for squat women. In a similar study, Cinel et al. found that the bench press was 72 ± 0.7 kg and the shoulder press was 88 ± 0.7 kg after working with reloading method in elite female volleyball players (Cinel et al., 2006). ...
Article
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The aim of this study is to evaluate the body composition, physical and physiological parameters of the functional (cross fit, HIIT) exercises applied at the beginning of the preparatory season and at the end of the preparatory season, and to determine the physical and physiological parameters that occur in female footballers during the preparatory season. The average age of the study was 22.25 ± 3.8 years, average height; 166.36 ± 8.14 cm and a weight average 2018-2019 season in Turkey with 54.44 ± 3.24 kg Football Federation Women 1st league's elite players and 20 female volunteers participated in the play. Statistical analysis of the data obtained as a result of the measurements was made using the SPSS 25.00 for Windows package program. Arithmetic means, standard deviations, and differences between the averages of the data obtained after the measurements were found. In order to compare the data obtained after the measurements of the subjects participating in the study with each other and to determine the significance levels of the differences between the averages, they were analyzed at the level of 0.05 significance using "Paired Samples T Test". As a result, in the light of the data obtained, it was determined that there were statistically significant differences in many parameters that were generally measured, except BMI values. It is believed that functional training, which is one of the determinants of performance, is due to the effect of female footballers on body composition and some physical parameters, and it is important to pay attention to functional training in regularly planned and created training contents.
... We admit that safety should be the foremost consideration especially in the cases of machine exercises. As mentioned earlier, we aimed to provide immersive VR exercise experience for machine exercises, considering their lower attention demand of body balance and enhanced safety [12] compared to free-weight exercises. However, JARVIS may need more extensive consideration for safety, for example, allowing a user to observe surrounding environment and to proactively handle potential threat. ...
Article
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With the advent of immersive virtual reality (VR) head-mounted displays (HMD), we envision that immersive VR will revolutionize the personal fitness experience in our daily lives. Toward this vision, we present JARVIS, a virtual exercise assistant that is able to provide an immersive and interactive gym exercise experience to a user. JARVIS is enabled by the synergy between Internet of Things (IoT) and immersive VR. JARVIS employs miniature IoT sensing devices removably attachable to exercise machines to track a multitude of exercise information including exercise types, repetition counts, and progress within each repetition in real time. Based on the tracked exercise information, JARVIS shows the user the proper way of doing the exercise in the virtual exercise environment, thereby helping the user to better focus on the target muscle group. We have conducted both in-lab experiments and a pilot user study to evaluate the performance and effectiveness of JARVIS, respectively. Our in-lab experiments with fifteen participants show that JARVIS is able to segment exercise repetitions with an average accuracy of 97.96% and recognize exercise types with an average accuracy of 99.08%. Our pilot user study with ten participants shows statistically significant improvements in perceived enjoyment, competence, and usefulness with JARVIS compared to a traditional machine exercise setting (p < 0.05). Finally, our surface electromyography (sEMG) signal analysis conducted during the pilot user study shows statistically significant improvement in terms of muscle activation (p < 0.01), indicating the potential of JARVIS in providing an engaging and effective guidance for machine exercises.
... Importantly, constraint-induced movement therapy with motor restriction to unimpaired extremities has well-documented and substantial beneficial effects on cortical plasticity and motor rehabilitation of the impaired extremity in stroke patients (Wolf et al. 2006). Furthermore, motor restrictions are often used to improve technical features in the context of sport (e.g., Cotterman et al. 2005) or ergonomics, for instance, when orthopedic or robotic devices are designed to prevent individuals from unhealthy postures and to provide motor guidance (Bettany-Saltikov et al. 2008;Carrozza et al. 2019; for an extended overview on the idea of motor restriction, see also Sperl, 2021). ...
Article
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Modifying established motor skills is a challenging endeavor due to proactive interference from undesired old to desired new actions, calling for high levels of cognitive control. Motor restrictions may facilitate the modification of motor skills by rendering undesired responses physically impossible, thus reducing demands to response inhibition. Here we studied behavioral and EEG effects of rule changes to typing in skilled touch-typists. The respective rule change—typing without using the left index finger—was either implemented per instruction only or with an additional motor restriction. In both groups, the rule change elicited delays and more errors in typing, indicating the occurrence of proactive interference. While stimulus-locked ERPs did not exhibit prominent effects of rule change or group, response-locked ERPs revealed that the time courses of preparatory brain activity preceding typing responses depended on the presence of motor restriction. Although further research is necessary to corroborate our findings, they indicate a novel brain correlate that represents changes in inhibitory response preparation induced by short-term motor restrictions.
... Despite numerous criticisms regarding Smith-machines and their transferability to applied settings, most literature in this space continues to employ them. Research suggests that mechanical outputs such as take-off velocity (directly related to peak velocity), maximum load lifted, and electromyographical muscle activity differ when performing Smith-machine exercises compared to free-weight, suggesting that the generalizability of this research to broader contexts using free-weight exercise is limited [37][38][39]. Future research should therefore seek to elucidate the predictive validity of approaches most represented in practice, such as free-weight upper and lower body exercises. ...
Article
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The study aim was to compare different predictive models in one repetition maximum (1RM) estimation from load-velocity profile (LVP) data. Fourteen strength-trained men underwent initial 1RMs in the free-weight back squat, followed by two LVPs, over three sessions. Profiles were constructed via a combined method (jump squat (0 load, 30–60% 1RM) + back squat (70–100% 1RM)) or back squat only (0 load, 30–100% 1RM) in 10% increments. Quadratic and linear regression modeling was applied to the data to estimate 80% 1RM (kg) using 80% 1RM mean velocity identified in LVP one as the reference point, with load (kg), then extrapolated to predict 1RM. The 1RM prediction was based on LVP two data and analyzed via analysis of variance, effect size (g/), Pearson correlation coefficients (r), paired t-tests, standard error of the estimate (SEE), and limits of agreement (LOA). p < 0.05. All models reported systematic bias < 10 kg, r > 0.97, and SEE < 5 kg, however, all linear models were significantly different from measured 1RM (p = 0.015 <0.001). Significant differences were observed between quadratic and linear models for combined (p < 0.001; = 0.90) and back squat (p = 0.004, = 0.35) methods. Significant differences were observed between exercises when applying linear modeling (p < 0.001, = 0.67–0.80), but not quadratic (p = 0.632–0.929, = 0.001–0.18). Quadratic modeling employing the combined method rendered the greatest predictive validity. Practitioners should therefore utilize this method when looking to predict daily 1RMs as a means of load autoregulation.
... According to literature, completely or partiallye.g., bar-guided-OKC squat (e.g., a Smith machine squat, for instance a squat exercise performed at the Smith machine Multipower [MP], read below) is generally preferred over CKC machines (e.g., leg press) by strength-training athletes, because the former exercise is thought to provide a more unstable exercise requiring a greater recruitment of trunk and lower limb musculature (Anderson and Behm, 2005;Schwanbeck et al., 2009). In fact, several studies indicate that OKCs may be preferable over CKC machines for recruiting the major muscle groups of the legs (Hogan, 1984;Haff, 2000;Cotterman et al., 2005). Closed kinetic-chain exercise machines, however, are easier to use by beginners and those with injuries in the early to mid-stages of rehabilitation protocols, as they are easier to control, require less trainer supervision compared to OKCs and expose the exerciser to lower overall injury risk (Haff, 2000). ...
Article
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First aim was describing Smith machine squat and leg press exercise as nominal load, knee extensors activity, and rating of perceived exertion. Second aim was developing predictive equations to provide same muscular activation and same perceived exertion nominal loads during the two exercises. To do that, vastus lateralis and vastus medialis activation, as their summed surface electromyography signal integrals, and overall perceived exertions were measured at different nominal loads during Smith machine squat and leg press exercise in adult male athletes experienced in weight training. Correlation and multistep stepwise analyses were performed. Then, two different results-driven predictive equations to provide same electromyography signals and same perceived exertion nominal loads were developed. The same electromyography signal equation results were less accurate (i.e., less predictive) due to high inter-individual differences, whereas the same perceived exertion equation results were more accurate, because perceived exertion is more related to the Smith machine squat and leg press exercise overall level of exertion than to the two single muscles that were investigated. In conclusion, these two equations represented an initial attempt to provide athletes and coaches with a new tool to mutually convert equivalent nominal loads during Smith machine squat and leg press exercise over a training period.
... Repetitions not covering the whole distance were not considered. Foot spacing on the half-squat was set at approximately the same width as, or slightly wider than, shoulder width while keeping toes pointing slightly outwards [26]. The torso was kept as straight as possible and a security belt was used by all participants [27]. ...
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Background The purpose of this study was to investigate the inflammatory response, lipid peroxidation and muscle damage in men and women athletes subjected to an acute resistance exercise. Methods Twenty college athletes (10 men and 10 women) performed a half-squat exercise consisting of five incremental intensities: 20%, 40%, 60%, 80% and 100% of the one-repetition maximum. Blood samples were collected at rest, 15 min and 24 h post-test. The concentration of lipid peroxidation markers and the activities of a skeletal muscle damage marker and a cardiac muscle damage marker were determined in serum. Serum α-actin was measured as a marker of sarcomere damage. Serum levels of interleukin-6, interleukin-10, and tumor necrosis factor alpha were determined to assess the inflammatory response. Results Interleukin-6 levels were higher at 24 h post-test than at rest and 15 min post-test in men (p < 0.05). Moreover, men showed significantly higher hydroperoxide levels in response to resistance exercise at 24 h post-test than at 15 min post-test (p < 0.05). No differences were found in muscle damage parameters regardless of sex or the time point of the test. No differences regarding the studied variables were found when comparing among different time points in women. Conclusion Our results show a larger influence of half-squat exercises on the release of IL6 and on lipid peroxidation in men than in women at equivalent workloads.
... This improvement in sensitivity of receptors and facilitation of work of the neuromuscular system will presumably contribute to the improvement in work effectiveness in long-term efforts (work economy). Cotterman, Darby, Skelly, (2005) compared two types of muscular work using free weights or Smith machine and found that the first work was more efficient. In both cases of 1RM tests, the level of generated power (i.e. ...
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Proper planning of the training process based on individual LT and AT metabolic thresholds is essential to improve athletic performance. Development of endurance in soccer players is mainly based on continuous runs and variable-intensity runs, supplemented with strength conditioning and sport-specific training. The aim of the study was to analyse selected parameters of physical capacity of soccer players after 8-week variable-intensity running training and circuit training. The experiment was carried out in a group of 34 soccer players aged 21 to 26 years. The athletes were divided into two groups: 17 people in the experimental group and 17 people in the control group. The experimental group was involved in 30-minute tempo runs two times a week for 8 weeks with variable intensity at AT. In the same period, the control group performed two 60-minute continuous runs at the intensity of 70-75%HRmax. The determination of metabolic thresholds used two indirect tests: the multistage shuttle run test (beep test) and maximal lactate steady state test (MLSS) with author's own modification. In order to evaluate maximal heart rate (HRmax), the research procedure was started from the beep test (distance: 20 m). The speed at the first level was 8.5 km/h and increased with each level by 0.5 km/h. Training of the experimental group where variable exercise intensity was used caused a statistically significant increase in HRmax (by 1.9%) and blood lactate levels at the AT (by 20.5%). The training in the experimental group led to the statistically significant (p < 0.05) increase in the parameters of the following variables: HRmax (by 1.9%); lactate level (by 7.85); HR at the AT (by 1,9%); lactate level at the AT (by 20.5%). The assumptions of the experimental training did not cause statistically significant changes in pretest vs. posttest HRmax and blood lactate levels for the LT. Endurance training with high intensity is more effective in soccer players compared to training with moderate intensity. Development of special endurance in soccer should also assume the intensity and method of working similar to the method used during sport competition.
... In addition, there are some differences between the exercises that could have influenced the results. For example, the performance of the bench press in the Smith machine provides a stable condition (29) and allows a less natural weight lifting than nonguided variations (13). However, our results suggest that these differences between the exercises seem to have less importance than the biomechanical similarities. ...
... assessment across 4 testing sessions, with no difference across testing sessions in individuals with little to moderate experience in resistance training (#6 months). In addition, the range of motion used during the squat exercise (full squat vs. parallel squat) and the use of a fixed barbell (Smith machine) for both bench press and squat exercises affect the results, validity, and reliability of the 1RM (10,12). ...
Article
The aim of this study was to determine the validity of performing 3 one repetition maximum (1RM) assessments for the push press (PP), push jerk (PJ), and split jerk (SJ) in sequence in one testing session vs. the criterion method (testing on separate days), while determining the between-session reliability of the combined assessment. Twenty-two well-trained men (n = 22; age: 28.5 + 1.3 years; height: 1.80 + 0.04 m; body mass: 84.9 + 1.9 kg; training experience: 4.27 + 4.08 years) participated in this study. The 1RM was assessed in a sequential order in the same testing session (combined 1RM assessment) for the PP, PJ, and SJ on 2 occasions, to determine between-session reliability. The 1RM for each exercise was also examined on 3 separate sessions to compare the results against the combined method. A high reliability, low variability, and low measurement error were evident for the PP (intraclass correlation coefficient [ICC] = 0.960; coefficient of variation [CV] = 1.8%; smallest detectable difference [SDD] = 7.1%), PJ (ICC = 0.978; CV = 1.5%; SDD = 5.4%) and SJ (ICC = 0.987; CV = 0.8%; SDD = 4.6%). In addition, there were no significant (p > 0.05) or meaningful (η2 ≤0.001) differences between the single and combined assessments. The high reliability and validity of the combined assessment suggest that practitioners and researchers may simplify the testing procedure by assessing the 1RM during the 3 main overhead pressing exercises in a single testing session.
... This may indicate that a greater learning effect occurs with the SSB as the difference in 1RM values between bars declined from 21.3 to 8.8% from pre-to-post training. Although only 2 other studies have investigated the SSB, the literature has been consistent in reporting significant differences between 1RM values when different versions of the squat are performed (e.g., front squat, belt squat, smith machine squat, and back squat) (7,10,14,31). In each study, subjects were able to perform higher intensities during the back squat. ...
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Vantrease, WC, Townsend, JR, Sapp, PA, Henry, RN, and Johnson, KD. Maximal strength, muscle activation, and bar velocity comparisons between squatting with a traditional or safety squat bar. J Strength Cond Res XX(X): 000-000, 2020-The purpose of this study was to compare strength, muscle activation, and bar velocity between the traditional (TRAD) and safety squat bar (SSB) back squat. Thirty-two men (21.94 ± 3.1 years, 1.78 ± 0.8 m, 81.7 ± 10.1 kg) volunteered to complete this randomized, crossover-design study. Subjects completed 2 separate 1 repetition maximum (1RM) sessions using either the TRAD or SSB. Subsequently, subjects completed 1 session of 3 repetitions at 65 and 85% of their 1RM for each squat condition (SSB & TRAD). Peak muscle activation of 7 muscles from the lower body and trunk was recorded through surface electromyography (EMG), and mean velocity (MV) was recorded by a linear transducer. Electromyography and MV were analyzed by a 2 × 2 (bar × load) repeated-measures analysis of variance. A Pearson correlation was used to determine the relationship of 1RM load between bars. Squat 1RM was significantly higher (p < 0.001; 11.6%) for TRAD (144.7 kg) compared with SSB (128.8 kg), and a strong correlation (r = 0.94) was observed between 1RM values of each bar. A significant main effect was seen in EMG (p < 0.001) and MV for load (p < 0.001). No significant bar × load interaction was observed between conditions for any EMG or bar velocity measure (p > 0.05). The SSB produces similar muscle activation and bar velocities compared with the TRAD at relative intensities. However, absolute loads should be adjusted when changing squat bars during a training cycle.
... As the stability demands of movement increase, the ability to produce net force decreases (Cotterman et al., 2005;Lyons et al., 2010), with the magnitude of the effect being dependent on the specific motor task and involved muscles groups. While some discrepancies between the stable and compliant ergometers have already been observed, no studies have investigated different approaches to creating an unstable ergometer design so far. ...
Article
This study compared biomechanical characteristics and physiological responses during rowing on three devices: (i) stable ergometer (STE), (ii) transversally compliant ergometer (TCE) and (iii) frontally compliant ergometer (FCE). Eleven young competitive rowers completed a 2000 meter simulated race under each of the ergometer conditions in a randomized order. Stroke rate, average force, power output, velocity and amplitude of the handle and stretcher or seat, heart rate and blood lactate were measured at 500 m intervals. Force and power at the stretcher were significantly lower (p < 0.03) for TCE, while stroke rate and velocities of the handle and the seat were higher (p < 0.01). No significant differences were observed between STE and FCE in biomechanical parameters. The lowest rowing performance was observed in FCE (p = 0.007), and was accompanied with the highest average heart rate (p = 0.031). Our findings indicate that in TCE, rowers modified their technique, but were able to maintain physiological strain and performance. In contrast, FCE had no effect on rowing biomechanics, but decreased rowing performance and increased physiological strain. It seems plausible that transversal, but not frontal compliance, elicited a biomechanical technique that might reduce the discrepancy between a rowing ergometer and on-water rowing.
... Measures were taken during single repetitions of concentric back-squats with increasing loads. This test was carried out on a Smith machine (Pivot680L; Pivot Fitness, Tianjin, China) to eliminate the stretch-shortening cycle and reduce the technical demands [16]. The barbell height was adjusted so each participant started from a 90 ° knee angle. ...
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The aim of this study was to examine the effects of overspeed or overload plyometric training on jump height and lifting velocity in resistance trained females without plyometric training experience. Fifty-six participants (age: 21.2±1.7 years; body mass: 65.1±8.2 kg; height: 168.0±5.9 cm) were randomly allocated to either an overspeed (n=18), overload (n=18), or passive control (n=16) group. The two training groups completed 18.7±1.7 sessions consisting of three different plyometric exercises with overspeed or overload over eight weeks. Apart from the external loading, the two training modalities were identical. Following the training period, the changes in the recorded variables were not significantly different from those in the control group, nor did the training groups differ from each other. The training groups improved peak and average lifting velocity in the 40 and 60% of body mass loading conditions (9.50–33.37%, p=<0.001–0.038), whereas only the average lifting velocity improved in the 80% of body mass loading condition (OS: 14.47%, p<0.001 and OL: 23.13%, p<0.001). No significant changes occurred in the control group (9.18–13.55%, P=0.062–0.980). Overspeed and overload plyometric training may be viable methods for improving lifting velocity, but not squat jump height, in a population without plyometric training experience.
... However, other inertial measurement units, such as the PUSH band 1.0, have previously been found reliable and valid compared to a single linear position transducer for Smith machine back squat mean velocity (ICC 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 = 0.907, r = 0.85) and peak velocity (ICC = 0.944, r = 0.91) (2). In contrast to the free weight exercises in the current study, the Smith machine fixes the barbell path in a linear motion, which reduces error in measurements from unaccounted horizontal motion making comparisons between methods rather difficult (8,9). This may be a reason for lower levels of validity previously noted when comparing the PUSH Band 2.0 to a single linear position transducer (33). ...
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This study evaluated the reliability and concurrent validity of the OUTPUT sports inertial unit to measure concentric velocity of free-weight back squat and bench press exercises. Eleven men and women performed back squat and bench press one-repetition maximum (1-RM) testing. One week later, subjects performed three repetitions of each exercise with 35, 45, 55, 65, 75, and 85% 1-RM (18 total repetitions). The OUTPUT and four cable-extension transducers (criterion) simultaneously recorded mean and peak velocity. The OUTPUT had acceptable reliability for all loads except 85% 1-RM for back squat and bench press (ICC=0.72-0.96, CV=0.03-0.12). High systematic biases existed for mean and peak velocity for the back squat and bench press, according to Bland-wide limits of agreement and ordinary least products regressions. According to Bland-Altman plots, OUTPUT tended to overestimate bench press velocity and overestimate back squat velocity at slower velocities. Least products regression analyses determined proportional bias existed for mean and peak velocity of the back squat and peak velocity of the bench press. In conclusion, researchers and practitioners are advised not to compare velocity estimates of the OUTPUT unit to criterion devices as these methods cannot not be used interchangeably. However, due to the demonstrated reliability when estimating mean and peak velocity, strength and conditioning practitioners may find the OUTPUT unit valuable for monitoring performance of the back squat and bench press exercises. Yet, caution should be taken when evaluating loads ≥85% 1-RM.
... This has been demonstrated in the bench press throw, as greater throw heights were achieved with AEL (+20-40 kg of additional bar mass) by reaching greater accelerations [27]. However, this was conducted using a Smith machine, which has a fixed bar path that is different than free weights [58]. During jump squats with 30% back squat 1-RM, AEL with an additional 20, 50, or 80% of the back squat 1-RM International Journal of Strength and Conditioning. ...
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Accentuated eccentric loading (AEL) employs heavier load magnitudes in eccentric actions than concentric actions of complete stretch-shortening cycles. In doing so, unique neuromuscular and molecular responses are expected to result in acute post-activation performance enhancements, as evidenced by increased movement velocity or power. Improvements are dependent upon load selection, which varies across exercises, such as jumps and bench press throws (eccentric: 20-40 kg or 20-30% of body mass; concentric: body mass only), and squats and bench press (eccentric: 77.3-120% One-Repetition Maximum (1-RM); concentric: 30-90% 1-RM). The efficacy of AEL is dependent upon the concentric load used, which in turn is influenced by the magnitude of the eccentric load. Greater strength relative to body mass may enable the maintenance of technique and pacing during AEL, necessary for resultant performance enhancements, particularly when using eccentric loads exceeding the individual’s concentric 1-RM. Before prescribing AEL practitioners should consider: training experience, strength relative to body mass, the particular exercise, AEL application method, and the magnitude of both eccentric and concentric loads. Thus, the aims of this brief review are to describe: 1) neuromuscular and molecular constructs of AEL; 2) acute effects of AEL; 3) chronic effects of AEL; 4) loading considerations; 5) practical applications.
... The use of a Smith machine with an inclined rail was a unique feature of this study for measurements of knee loads because prior studies using Smith machines for squats were either limited to the analysis of 1-RM loads [35] or to the assessment of muscle activation [36]. The use of this particular equipment is beneficial as it can help inform exercise prescription for recreational use of strength training, maintenance of health and rehabilitation. ...
Article
BACKGROUND: Comparison of knee loads on a Smith machine, which utilised in for maintenance of health and rehabilitation, has not been attempted. OBJECTIVE: This study compared lower limb muscle and knee joint forces during front and back squats performed on a Smith Machine. METHODS: Eleven participants performed front and back squats with loads at 40%, 60% and 80% of their back squat 1-RMs. Ground reaction forces and three-dimensional full body motion were collected and used for modelling lower limb muscle and knee joint forces. RESULTS: Larger loads increased tibiofemoral compressive force during back squat at 80% compared to 40% (p< 0.01; d= 1.58) and to 60% (p< 0.01; d= 1.37). Patellofemoral compressive (p= 0.96) and tibiofemoral shear forces (p= 0.55) were not influenced by external load or type of squat. Gluteus medius and minimus produced more force at 80% compared to 60% (p= 0.01; d= 1.10) and to 40% (p< 0.01; d= 1.87) without differences for other muscles (p= 0.09–0.91). CONCLUSIONS: Greater external load was associated with increase in gluteus medius and minimus force and with increased tibiofemoral compressive force without effects on tibiofemoral shear force, patellofemoral compressive force or other lower limb muscle forces.
... However, during free-weight barbell-based exercise, the device was unable to accurately determine velocity measures with heavy loads (.80% 1RM) (5), likely due to the increased variability of technique during such tasks (9). Although Smith machine-based exercise can be included into resistance training programs for reasons such as reducing demands on coordination and stability for athletes new to strength training (1), the advantages of performing free-weight exercises are well documented (8,23), particularly for the development of muscular strength and power. Furthermore, velocity-based monitoring is more likely to occur in well-trained cohorts who typically use free weights rather than Smith machine-based exercises. ...
Article
Hughes, LJ, Peiffer, JJ, and Scott, BR. Reliability and validity of using the Push Band v2.0 to measure repetition velocity in free-weight and Smith machine exercises. J Strength Cond Res XX(X): 000-000, 2019-The purpose of this study was to investigate the test-retest reliability and concurrent validity of using the Push Band device 2.0 (PUSH) to quantify repetition velocity across 4 common resistance training exercises performed using free-weight and Smith machine training modalities. Twenty well-trained men (age: 25.1 ± 2.9 years, height: 182.4 ± 6.0 cm, body mass: 77.9 ± 12.0 kg, training age: 5.2 ± 1.4 years) visited the laboratory on 6 occasions (3 free-weight and 3 Smith machine sessions). Baseline strength assessments were conducted in the first session with each modality for squat, bench press, overhead press, and prone row exercises. The subsequent sessions featured repetitions performed with 30, 60, and 90% 1-repetition maximum. During these sessions, velocity was measured simultaneously using a validated linear position transducer (LPT; considered the criterion for this study) and 2 PUSH devices, one in body mode (PUSHBODY) and the other bar mode (PUSHBAR). Test-retest reliability was examined using the intraclass correlation coefficient (ICC) and coefficient of variation (CV). The LPT demonstrated slightly greater reliability (ICC = 0.80-0.98, CV = 0.4-5.1%) than the PUSHBODY (ICC = 0.65-0.95, CV = 0.8-6.9%) and PUSHBAR (ICC = 0.50-0.93, CV = 0.7-7.1%) devices. Near-perfect correlations existed between velocity measured using LPT and PUSH devices (r = 0.96-0.99). No significant differences existed between mean velocity measures obtained using LPT and either PUSH device. The PUSH device can be used in either bar or body mode to obtain reliable and valid repetition velocity measures across a range of loads and exercises performed using either free weights or a Smith machine.
... Indeed, technique variation across a set can increase perceived difficulty due to poor lifting mechanics rather than proximity to muscular failure. Given that individuals are instructed to estimate RIR based primarily on the perceived difficulty of the last repetition, machine-based exercises may improve RIR estimations as they allow more consistent technique compared with free-weights (2,9,10). Finally, the accuracy of RIR estimates is negatively influenced by the total number of repetitions performed (27). ...
Article
This study aimed to determine the accuracy and reliability of estimating repetitions in reserve (RIR) across the squat, bench press, overhead press and prone row exercises, using both free-weight and Smith machine modalities. Twenty-one trained males attended the laboratory on 14-occasions. They were assessed for 1RM for the squat, bench press, prone row and overhead press exercises and subsequently completed six RIR testing sessions using 65%, 75% and 85% 1RM. In these trials, subjects indicated when they reached 2-RIR (i.e. perceive they could only perform two more repetitions), before continuing the set to failure. The same process was then replicated using the alternative equipment modality. To determine accuracy of 2-RIR estimates, one-sample t-tests assessed differences between 2 and the actual number of repetitions completed after subjects indicated they had reached 2-RIR. Intraclass correlation coefficients (ICC) were used to determine the reliability of test-retest RIR estimated. There were no clear differences in the accuracy or reliability of estimating RIR between free-weight and Smith machine exercises. Load however, proved an important factor with the highest accuracy associated with RIR estimations performed when using 85%, followed by 75% and 65% 1RM respectively. When using loads of 75% and 65% 1RM it was increasingly likely that individuals would underestimate RIR by >1-repetition, which would practically lead to an undesired reduction in training volume. These results highlight that while estimates of 2-RIR may be accurate and reliable in heavy load resistance training (≥85% 1RM), practitioners should be wary of using this measure with lighter loads.
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ABSTRACT: The aim of this study was to compare the test performances of one repetition maximum in the barbell bench press and dumbbell bench press exercises. The study has a quasi experimental design, with a cross-over design. Participants included 10 healthy men, with minimum experience of six months of resistance training. Participants performed their respective one repetition maximum bench press exercise. To compare strength performance between exercises, was used the Univariate Analysis of Covariance, being age and body mass index covariates. Statistical analysis was performed through SPSS 21.0, being adopted a significant value of p <0.05.A Cohen effect size was verified (p = 0.7), and a significant difference between exercises (p <0.001), with the barbell bench press having a greater average value (84.4 ± 13.50) compared to dumbbells (70.2 ± 8.87). There was no interaction of age (p <0.69) and body mass index (p <0.40) with the performance in the exercises. The results showed greater strength performance in the barbell bench press compared to dumbbells.
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Purpose: This study examined the reliability of peak velocity (PV), mean propulsive velocity (MPV), and mean velocity (MV) in the development of load-velocity profiles (LVP) in the full depth free-weight back squat performed with maximal concentric effort. Methods: Eighteen resistance-trained men performed a baseline one-repetition maximum (1RM) back squat trial and three subsequent 1RM trials used for reliability analyses, with 48-hours interval between trials. 1RM trials comprised lifts from six relative loads including 20, 40, 60, 80, 90, and 100% 1RM. Individualized LVPs for PV, MPV, or MV were derived from loads that were highly reliable based on the following criteria: intra-class correlation coefficient (ICC) >0.70, coefficient of variation (CV) ≤10%, and Cohen's d effect size (ES) <0.60. Results: PV was highly reliable at all six loads. Importantly, MPV and MV were highly reliable at 20, 40, 60, 80 and 90% but not 100% 1RM (MPV: ICC=0.66, CV=18.0%, ES=0.10, standard error of the estimate [SEM]=0.04m·s(-1); MV: ICC=0.55, CV=19.4%, ES=0.08, SEM=0.04m·s(-1)). When considering the reliable ranges, almost perfect correlations were observed for LVPs derived from PV20-100% (r=0.91-0.93), MPV20-90% (r=0.92-0.94) and MV20-90% (r=0.94-0.95). Furthermore, the LVPs were not significantly different (p>0.05) between trials, movement velocities, or between linear regression versus second order polynomial fits. Conclusions: PV20-100%, MPV20-90%, and MV20-90% are reliable and can be utilized to develop LVPs using linear regression. Conceptually, LVPs can be used to monitor changes in movement velocity and employed as a method for adjusting sessional training loads according to daily readiness.
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Amaç: Araştırmanın amacı, sedanter bireylerin çoklu itiş makinesi ve serbest ağırlıklarla yapılan çalışmalarda üst ekstremiteye yönelik kuvvet gelişimlerinin karşılaştırılarak, cihaz etkinliğinin araştırılması ve bunlara bağlı olarak üst ekstremite kuvvetini hangi cihazın daha çok ve hangi yönde etkilediğini araştırmaktır. Yöntem: Araştırmamıza, 18-53 yaş arası spor geçmişi olmayan, herhangi bir sağlık problemi bulunmayan 22 (29,04±10,55 (Ortalama±SS)) birey katılmıştır. Örneklem Serbest Ağırlık Çalışma grubu (SAG) ve Smith Machine çalışma grubu (SMG) olarak iki gruptan oluşmaktadır. Araştırma gruplarına boy, kilo, esneklik, sırt kuvveti, el pençe kuvveti, alt ekstremite uzunluğu, üst ekstremite uzunluğu, kas kuvveti ölçümleri yapılmıştır. Analizler SPSS 21.0 paket programında yapılmıştır. Verilerin değerlendirilmesinde tanımlayıcı istatistik, Bağımsız İki toplum Ortalamasına dayalı iki örneklem T testi (Two Independent Samples T test) ve Bağımlı İki toplum farklarının ortalamasına dayalı iki örneklem T testi (Two related Samples T test, Paired T test) kullanılmıştır. Bulgular: Araştırmamızda, her iki grubun ön test ve son test puanları arasında istatiksel olarak anlamlı farklılık bulunmuştur (p<0,05). İki grubu birbiri ile karşılaştırdığımızda istatiksel olarak anlamlı farklılık bulunamamıştır (p>0,05). Fakat her iki grupta ayrı ayrı ön test-son test arasındaki farklara bakıldığında SMG grubunda kuvvet artış ortalaması 1,25 iken SAG grubunda bu oran 2,36 olarak bulunmuştur. Sonuç: 8 hafta boyunca Smith makinesi ve serbest ağırlıkla yapılan çalışmaların kuvvet gelişimi üzerine pozitif etkisi vardır. İki grup arasındaki kuvvet artışlarına bakıldığında, gruplar arası fark az olmasına karşın bu fark uzun süreli çalışmalarda katlanarak büyüyeceğinden zamanla, dahada anlamlılık kazanacaktır. Anahtar kelimeler: Kuvvet, üst ekstremite, serbest ağırlık, smith
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The use of smartphones and wearables as sensing devices has created innumerable context inference apps including a class of workout tracking apps. Workout data generated by mobile tracking apps can assist both users and physicians in achieving better health care, rehabilitation, and self-motivation. Previous approaches impose extra burdens on users by requiring users to select types of exercises or to start/stop sessions. In this paper we propose MiLift, a practical end-to-end workout tracking system that performs automatic segmentation to remove user burdens. MiLift uses commercial off-the-shelf smartwatches to accurately and efficiently track both cardio and weightlifting workouts without manual inputs from users. For weightlifting tracking, MiLift supports both machine-based and free weight exercises, and proposes a lightweight repetition detection algorithm to ensure efficiency. A research study of 22 users shows that MiLift can achieve above 90% average precision and recall for cardio workout classification, weightlifting session detection, and weightlifting type classification. MiLift can also count repetitions of weightlifting exercises with an average error of 1.12 reps (out of an average of 9.65). Our empirical app study on a Moto 360 watch suggests that MiLift can extend watch battery lives by up to 8.25x (19.13h) compared with previous approaches.
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RESUMEN: El objetivo de este estudio fue determinar la relación entre la masa muscular apendicular y la repetición máxima (RM) en sentadilla con barra (ST), press banca plano (PB) y peso muerto (PM) en sujetos físicamente activos que practican musculación. Este estudio correlacional se desarrolló con un enfoque cuantitativo y un diseño de campo, veinte sujetos sanos capacitados (14 hombres y 6 mujeres) en el entrenamiento con sobrecargas participaron voluntariamente en este estudio. El análisis estadístico consistió en aplicar la prueba de normalidad de Shapiro-Wilk y el coeficiente correlacional de Pearson, para ello se utilizó el paquete estadístico IBM SPSS V.22 con un nivel de confianza del 95% por lo que el p-valor empleado fue de 0,05. Los hombres tuvieron una masa muscular en miembros superiores (MMMS) de 6,49+1,37 kg y una masa muscular en miembros inferiores (MMMI) de 11,98+1,43 kg. En cambio, las mujeres mostraron una MMMS de 3,90+0,63kg, y en MMMI de 8,43+1,05kg. Los hombres obtuvieron un promedio en el 1RM ST 122,09+28,54 kg, 1RM PB 83,07+24,54 kg y 1RM PM 94,58+16,49 kg, mientras que las mujeres tuvieron 1RM ST 93,40+24,60 kg, 1RM PB 28,13+13,38 kg y 1RM PM 71,81+8,75 kg, por lo cual los hombres presentaron mejores resultados de MMMS, MMMI y 1 RM con respecto a las mujeres. Por otro lado, se obtuvo una distribución normal de los datos (p>0,05), aunque no se evidencio una relación significativa entre la MMMS y MMMI con el 1 RM de los ejercicios evaluados (p>0,05). Por consiguiente, se concluye que no existe relación significativa entre la masa muscular apendicular y la repetición máxima en los ejercicios ST, PB y PM en practicantes de musculación. Palabras Clave: Estudio correlacional, fuerza, masa muscular apendicular, repetición máxima. ABSTRACT: The objective of this study was to determine the relationship between appendicular muscle mass and maximum repetition (RM) on squat with bar (SB), banch press (BP) and deadlift (DL) in subjects physically active practicing bodybuilding. This correlational study was developed with a quantitative approach and design of field, twenty trained healthy subjects (14 men and 6 women) in training with overloading voluntarily participated in this study. Statistical analysis consisted of applying the Shapiro-Wilk normality test and the Pearson correlation coefficient, was used the statistical package SPSS IBM V.22 with a 95% confidence level so that the employee p-value was 0,05. The men had a muscle mass in upper limbs (MMUL) of 6,49+1,37 kg and a muscle mass in the lower limbs (MMLL) of 11,98+1,43 kg. On the other hand, women showed a MMUL of 3,90+0,63 kg, and at MMLL of 8,43+1,05 kg. The men obtained an average in the 1RM in SB of 122,09+28, 54 kg, 1RM BP of 83,07+24,54 kg and 1RM DL of 94,58+16,49 kg, while women had 1RM SQ of 93,40+24,60 kg, 1RM PB of 28,13+13,38 kg and 1 RM DL of 71,81+8,75 kg, which men presented MMUL best results, position and 1 RM with regard to women, on the other hand was a normal distribution of data (p>0,05), Although was not evidence a significant relationship between the MMUL and MMLL with 1 RM of the evaluated exercises (p>0,05). Therefore, it is concluded that not significant relationship between appendicular mass muscle and maximum repetition in the exercises SQ, BP and DL practitioners of bodybuilding. Key words: Correlational study, strength, muscle mass appendicular, maximum repetition.
Article
Employing an arched back posture during the bench press exercise is increasingly popular. Vertical displacement of the barbell is commonly believed to be the key difference influencing strength performance between an arched and flat back bench press technique. However, comparisons between these back postures using a free weight barbell are lacking. Directly comparing performance between each posture is confounded by many variables such as proficiency and fatigue. This investigation aimed to investigate whether changing back posture alone can influence barbell kinematics, to indirectly assess potential performance differences. Twenty males performed one repetition of the bench press exercise using either an arched or flat back posture, at 25%, 50% and 75% of their one repetition maximum, in a repeated measures study design. Statistical significance was considered at p < 0.05. Changing back posture alone, reduced vertical displacement (approximately 11% average difference across all load conditions) and barbell to glenohumeral joint moment arm (approximately 20% difference) in the arched posture compared to the flat posture. These changes occurred without any specific cueing of the barbell motion and may increase the potential for lifting higher loads and decrease cumulative joint exposure. Additional cueing and training may be required to maximize the mechanical advantage available with each back posture. The arched posture appears to have an increased potential for further improvements in vertical displacement and moment arm through specific cueing. Future comparisons should consider if each back posture’s potential mechanical advantage has been maximized when assessing differences between techniques.
Article
Williams, TD, Esco, MR, Fedewa, MV, and Bishop, PA. Bench press load-velocity profiles and strength after overload and taper microcyles in male powerlifters. J Strength Cond Res XX(X): 000-000, 2020-The purpose of this study was to quantify the effect of an overload microcycle and taper on bench press velocity and to determine if the load-velocity relationship could accurately predict 1-repetition maximum (1RM). Twelve male powerlifters participated in resistance training structured into an introduction microcycle, overload microcycle (PostOL), and taper (PostTP). At the end of each microcycle, subjects completed a bench press for 1RM assessment consisting of warm-up sets at 40, 55, 70, and 85% of a previously established 1RM. The mean concentric velocity (MCV) was recorded during each warm-up set. A predicted 1RM (p1RM) was calculated using an individualized load-velocity profile (LVP). The average MCV decreased after PostOL (0.66 ± 0.07 m·s) compared with baseline (BL) (p = 0.003; 0.60 ± 0.11 m·s) but increased after PostTP (0.67 ± 0.09 m·s). One-repetition maximum increased from PostOL (146.7 ± 19.8 kg) to PostTP (p = 0.002; 156.1 ± 21.0 kg), with no differences observed between other test sessions (p > 0.05). Bland-Altman analysis indicated that p1RM was consistently higher than measured 1RM (3.4-7.8 kg), and the limits of agreement were extremely wide. However, very large to near perfect correlations (r = 0.89 to 0.96) were observed between p1RM and 1RM during BL, PostOL, and PostTP. The load-velocity relationship established from submaximal sets did not accurately predict 1RM, but MCV was affected by changes in weekly training loads. Velocity-based measurements seem to be more sensitive to changes in training loads than maximal strength.
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Penelitian ini bertujuan untuk menguji pengaruh latihan squat menggunakan free weight dan gym machine terhadap kekuatan, power, dan hypertrophy otot; dan menguji perbedaan pengaruh latihan squat menggunakan free weight dan gym machine terhadap kekuatan, power, dan hypertrophy otot. Penelitian ini adalah penelitian eksperimen dengan desain two group pretest-posttest design. Sampel dalam penelitian ini dipilih berdasarkan teknik random sampling berjumlah 32 orang. Instrumen untuk mengukur kekuatan menggunakan back and leg dynamometer merk Takei buatan Jepang. Instrumen untuk mengukur power menggunakan Jump Duration of Fright (JDF) seri TKK 5114 buatan Jepang, satuan sentimeter. Instrumen untuk mengukur lingkar otot paha menggunakan meteran dengan satuan sentimeter. Teknik analisis data yang digunakan adalah analisis multivariat pada taraf signifikansi α = 0,05. Hasil penelitian menunjukkan bahwa (1) ada pengaruh yang signifikan latihan squat menggunakan free weight terhadap kekuatan, power, dan hypertrophy otot, (2) ada pengaruh yang signifikan latihan squat menggunakan gym machine terhadap kekuatan, power, dan hypertrophy otot, dan (3) ada perbedaan yang signifikan antara latihan squat menggunakan free weight dan latihan squat menggunakan gym machine terhadap kekuatan, power, dan hypertrophy otot. Persentase kenaikan nilai pretest dan posttest kekuatan, power, dan hypertrophy otot menunjukkan kelompok latihan squat menggunakan free weight lebih baik daripada kelompk gym machine. The influence of squat practice using free weight and gym machine on the strength, the muscle and the hypertrophy of the muscle AbstractThe study aims at testing the influence of squat training using free weight and gym machine on the strength, the power and the hypertrophy of the muscle and at testing the differences between the influence of squat training using free weight and the influence of squat training using gym machine on the strength, the power and the hypertrophy of the muscle. The study is an experiment with two group pre-test-post-test design. Then, the samples for the study were selected based on the random sampling technique and the total number of the respondents was 32 people. The instrument for measuring the strength of the muscle was back and leg dynamometer Takei made in Japan while the instrument for measuring the power of the muscle was Jump Duration of Fright (JDF) series TKK 5114 made in Japan with centimetre unit. Furthermore, the instrument for measuring the circle of the tight muscle was a gauge with centimetre unit. The results of the study show that: (1) the squat training using the free weight has significant influence on the strength, the power and the hypertrophy of the muscle; (2) the squat training using the gym machine has significant influence on the strength, the power and the hypertrophy of the muscle; and (3) there has been significant difference between the squat training using the free weight and the squat training using the gym machine on the strength, the power and the hypertrophy of the muscle. The increasing percentage from the pre-test score into the post-test score in the strength, the power and the hypertrophy of the muscle shows that the training group that performs the squat training using the free weight has better performance than the group that performs the squat training using the gym machine.
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The purpose was to evaluate the acute effects of accentuated eccentric loading (AEL) on bench press velocity and subsequent perceived effort (RPE) and soreness. Resistance-trained men (n=8) and women (n=2) completed 4 sets of 5 bench press repetitions with AEL and traditional loading (TL) using concentric loads of 50% (AEL50, TL50) and 65% (AEL65, TL65) one-repetition maximum (1-RM). Throughout each TL set, the eccentric load remained identical to the concentric. Variable resistance during the first repetition of AEL equaled 120% 1-RM. Hierarchical Linear Modeling was used to evaluate differences between AEL and TL (p<0.05). For the first repetition, AEL50 and AEL65 resulted in slower eccentric and concentric velocities. The increasing slope of eccentric and concentric velocity across repetitions was greater during AEL50 and AEL65 compared to TL50 and TL65, respectively (p<0.05). As an individual’s strength increased, AEL50 resulted in slower eccentric velocity and faster concentric velocity than TL50. The AEL65 resulted in faster concentric velocity than TL65 (p<0.05). Mean protocol comparisons revealed trivial to small effects between AEL and TL. There were no differences in RPE or soreness between protocols with soreness ratings remaining unchanged from baseline (1.80±0.20 AU; p<0.05). Overall, AEL was not effective for increasing concentric velocity during the bench press with current loading protocols. Yet, stronger individuals may exhibit increases in concentric velocity from AEL, which may be a result of different pacing strategies employed during the eccentric phase. Further, when using the current AEL protocols, eccentric intensities were increased with no greater RPE or soreness.
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This study was conducted to determine the relationship between the performances of one repetition maximums (1-RM) of selected free weight and Universal machine exercises. Subjects, 57 young women and 67 young men, performed a 1-RM for the Universal bench press (UBP), free weight bench press (FWBP), Universal leg press (ULP), and free weight parallel squat (FWPS). Test correlations were significant (p < 0.05) for both genders: women, upper body, r = 0.95; lower body, r = 0.66; men, upper body, r = 0.94; lower body, r = 0.67. Eight regression equations were developed to predict 1-RM for UBP, FWBP, ULP, and FWPS. These equations may be useful to coaches and athletes who wish to convert to the approximate weight needed for a lift when switching from one type of resistance equipment to another. (C) 1997 National Strength and Conditioning Association
Article
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1. Skinfold thickness, body circumferences and body density were measured in samples of 308 and ninety-five adult men ranging in age from 18 to 61 years. 2. Using the sample of 308 men, multiple regression equations were calculated to estimate body density using either the quadratic or log form of the sum of skinfolds, in combination with age, waist and forearm circumference. 3. The multiple correlations for the equations exceeded 0.90 with standard errors of approximately ±0.0073 g/ml. 4. The regression equations were cross validated on the second sample of ninety-five men. The correlations between predicted and laboratory-determined body density exceeded 0.90 with standard errors of approximately 0.0077 g/ml. 5. The regression equations were shown to be valid for adult men varying in age and fatness.
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The performance of ten elite powerlifters were analyzed in a simulated competition environment using three-dimensional cinematography and surface electromyography while bench pressing approximately 80% of maximum, a maximal load, and an unsuccessful supramaximal attempt. The resultant moment arm (from the sagittal and transverse planes) of the weight about the shoulder axis decreased throughout the upward movement of the bar. The resultant moment arm of the weight about the elbow axis decreased throughout the initial portion of the ascent of the bar, recording a minimum value during the sticking region, and subsequently increased throughout the remainder of the ascent of the bar. The electromyograms produced by the prime mover muscles (sternal portion of pectoralis major, anterior deltoid, long head of triceps brachii) achieved maximal activation at the commencement of the ascent phase of the lift and maintained this level essentially unchanged throughout the upward movement of the bar. The sticking region, therefore, did not appear to be caused by an increase in the moment arm of the weight about the shoulder or elbow joints or by a minimization of muscular activity during this region. A possible mechanism which envisages the sticking region as a force-reduced transition phase between a strain energy-assisted acceleration phase and a mechanically advantageous maximum strength region is postulated.
Article
In brief: Sexual differences in athletic performance are largely due to variations in body size, body composition, aerobic power, and muscular strength. This article reviews the literature on sexual differences for these variables and examines both absolute and relative differences to determine whether they are caused by the biological factor of sex or by cultural influences. The authors conclude that although physiological values for the average man are statistically different from the average woman, differences between any two individuals of the same sex are often greater. Even though sexual differences can be greatly reduced or eliminated by using relative values, their larger size gives men a practical physical advantage in many athletic and daily activities.
Article
The purpose of this study was to determine the effects of grip width, chest depth, limb lengths, and bar path on the performance of a maximal bench press. Subjects were 24 experienced male weight trainers. Bench press performance was assessed at six different grip widths (G1–G6). Repeated-measures ANOVA with Tukey post hoc comparisons revealed that bench press strength values at the two moderate grip widths (G3 and G4) were significantly greater than either the narrow or wide grip widths. First-order partial correlations showed no significant relationship between strength values and anthropometric variables when adjusted for differences in body weight. Standard two-dimensional cinematographic procedures were used to film a subsample (n = 6) while bench pressing using G1, G3, and G6. The results of the statistical comparisons of bar path indicated that as grip width increased, the horizontal and vertical distance from the bar to the shoulder decreased.
Article
The purpose of this study was to examine gender differences in upper and lower body strength as a function of lean body weight and the distribution of muscle and subcutaneous fat in the upper and lower limbs. The subjects were 103 physically active men (n = 48) and women (n = 55). The peak torques produced during shoulder flexion (SF) and knee extension (KE) were used as measures of upper body and lower body strength, respectively. Flexed arm girth, thigh girth, triceps skinfold, and thigh skinfold were used to estimate the distribution of muscle and subcutaneous fat in the limbs. Results of the MANOVA revealed that the overall strength of men was significantly greater than that of women. Results of MANCOVA indicated that the SF and KE strength of women and men did not differ significantly when differences in lean body weight, arm girth, thigh girth, triceps skinfold and thigh skinfold were statistically controlled. High levels of SF and KE strength were associated with a high lean body weight and a large arm girth. Results of the multiple regression analysis indicated that for men a substantial portion of the variance in both SF and KE strength was explained by lean body weight alone; whereas strength variations in women were explained more adequately by including limb variables along with lean body weight. Within the limitations of this study, it was concluded that gender differences in upper and lower body strength are a function of differences in lean body weight and the distribution of muscle and subcutaneous fat in the body segments. Upper body strength is relatively more important than lower body strength in characterizing the gender difference in strength.
Article
The purpose of this study was to formulate a kinematic model of performance in the parallel squat, based on the movement characteristics of world class powerlifters, and to determine if the model could be utilized to assess technique differences between high and less-skilled subjects. Two trials were recorded via high-speed cinematography from a side view of twenty-four Ss during the 1974 U.S. Senior National A.A.U. Powerlifting Championships. Vertical and horizontal displacement patterns of three joint centers and the center of the bar were determined for the best trial of each S. These data were subsequently used to calculate desired linear and angular coordinates, velocities and accelerations for body segments and bar. Results indicated that although there was some variability in most kinematic parameters, vertical bar velocity was found to be very similar among competitors, even for Ss of different bodyweight. Consequently, the vertical velocity of the bar was selected as the parameter around which performance could be modeled in the parallel squat. A model was formulated by plotting the mean values in vertical bar velocity for all Ss scaled to a common time base. The resultant model was contrasted with vertical bar velocity data for less-skilled Ss to assess typical performance errors. (C)1977The American College of Sports Medicine
Article
The purpose of this study was to determine the effect of grip width on myoelectric activity of the pectoralis major, anterior deltoid, triceps brachii, and biceps brachii during a 1-RM bench press. Grip widths of 100,130,165, and 190% (G1, 2, 3, 4, respectively) of biacromial breadth were used. Mean integrated myoelectric activity for each muscle and at each grip width was determined for the concentric portion of each 1-RM and normalized to percentages of max volitional isometric contractions (%MVIC). Data analysis employed a one-factor (grip width) univariate repeated measures ANOVA. Results indicated significant main effects for both grip width (p = 0.022) and muscles (p = 0.0001). Contrast analyses were conducted on both main effects. Significant differences (p <= 0.05) were found between grip widths G4 and both Gl and G2 relative to %MVIC. Significant %MVIC differences on the muscles main effect were also found. All prime movers registered significantly greater %MVICs than the biceps and, in addition, the triceps %MVIC was greater than the pectoralis major. (C) 1997 National Strength and Conditioning Association
Article
This study calculated IEMG values during the ascent and descent phases of the bench press and compared the values between lifts performed with free weights versus a guided weight machine. In Phase 1 of the study the 1-RM on each mode was determined for each subject. In Phase 2, EMG data were collected from five muscles of the upper extremity while each subject completed five trials at 80% of 1-RM and five trials at 60% of 1-RM for each mode. Linear envelopes were created from the EMG data of each trial, and IEMG values were calculated during the descent and ascent phases of each trial. Planned comparisons were used to compare mean IEMG values between the two loads within the same mode, and between the two modes at both the 60% and 80% loads. Results suggested greater muscle activity during the free-weight bench press, especially at the 60% 1-RM load, although there were notable differences among the patterns of individual subjects.
Article
This study investigated the muscular torques and joint forces during the parallel squat as performed by weightlifters. (JD)
Article
The purpose of this study was to formulate a kinematic model of performance in the parallel squat, based on the movement characteristics of world class powerlifters, and to determine if the model could be utilized to assess technique differences between high and less-skilled subjects. Two trials were recorded via high-speed cinematography from a side view of twenty-four Ss during the 1974 U.S. Senior National A.A.U. Powerlifting Championships. Vertical and horizontal displacement patterns of three joint centers and the center of the bar were determined for the best trial of each S. These data were subsequently used to calculate desired linear and angular coordinates, velocities and accelerations for body segments and bar. Results indicated that although there was some variability in most kinematic parameters, vertical bar velocity was found to be very similar among competitors, even for Ss of different bodyweight. Consequently, the vertical velocity of the bar was selected as the parameter around which performance could be modeled in the parallel squat. A model was formulated by plotting the mean values in vertical bar velocity for all Ss scaled to a common time base. The resultant model was contrasted with vertical bar velocity data for less-skilled Ss to assess typical performance errors.
Article
Strength training has become quite popular and is now recommended as part of a well-balanced fitness program in healthy individuals. It is also useful in a wide variety of other clinical circumstances. An understanding of the pertinent basic science and research endeavors will help in the design and prescription of safe, effective programs.
Article
Women and men respond to strength training in very similar ways from their individual pretraining baselines. Women on the average have smaller bodies than men, have less absolute muscle mass and smaller individual muscle fibers, and display approximately two-thirds of the absolute overall strength and power of men. In addition, children are enculturated to view strength as masculine, an outlook which has depressed the pursuit and performance of strength activities by women. However, unit for unit, female muscle tissue is similar in force output to male muscle tissue, and there is some evidence to support similar, proportional increases for the sexes in strength performance and hypertrophy of muscle fibre relative to pretraining status. Strength training can also provide beneficial alterations in bone, body fat and self-concept in women. There is no evidence that women should train differently than men, and training programmes should be tailored for each individual.
Article
The purpose of the study was to evaluate selected parameters describing performance characteristics of a free-weight and isokinetic bench press. A secondary purpose was an attempt to clarify the technique requirements essential for a successful lift. Parameters describing the free-weight condition were generated from cinematographic data (150 fps) for five trials each at 90 and 75% of the subject's maximal performance (1RM). Isokinetic data were obtained from an instrumented Cybex Power Bench Press at two speeds corresponding to the average speeds for the free-weight conditions. Despite differences, accommodation appeared to occur for both methods when the lifts were performed maximally. A "sticking region" was defined as the portion of the free-weight activity when the subjects' force application was less than the weight of the bar. No significant difference (P less than 0.05) was observed between the 90% 1RM (26.02%) and 75% 1RM (26.94%) mean relative time values for these regions. For the Cybex device, the percentage of the activity which was isokinetic was longer for the slower speeds of rotation (0.47 rad X s-1 = 70%) and steadily decreased until the movement was only 50% isokinetic at 1.74 rad X s-1. The observed relationships between applied force-time data along with anatomical considerations suggest an ideal technique for the lift.
Article
This study compared untrained men with trained women body builders in terms of absolute and relative upper and lower body strength. Relative strength was expressed per unit of height, weight, biacromium and biiliac width. Analysis of the data by a one-way ANOVA indicated that upper body strength in untrained men is significantly stronger than in trained women in absolute terms, but no difference was found in lower body strength between the contrasted groups. When body characteristics were controlled by using an ANCOVA there were no significant differences in upper and lower body strength between the groups, although a trend appeared in which the men were stronger on the upper body and women were stronger on the leg flexors with little difference on the leg extensors.
Article
Forty-seven women and twenty-six men volunteered to participate in a 10-week program of intensive weight training, with an average attendance of two days per week, 40 minutes per session. Assessments of strength, body composition and anthropometric girths, diameters and skinfolds were made at the beginning and at the conclusion of the study period. Both groups made similar relative gains in strength and absolute gains in body composition. The men were stronger than the women for all strength measures, although the women exhibited a greater leg strength when expressed relative to lean body weight. Muscular hypertrophy evident in both groups, was confined basically to the upper extremity, and was of substantially greater magnitude in the males. Correlations between absolute strength and girth size indicate a probable relationship between muscle size and strength, but hypertrophy is not a predominant consequence of increasing total body or individual muscle strength. (C)1974The American College of Sports Medicine
Article
The purpose of this research was to identify kinematic factors that could be relevant to performance and injury risk in the bench press. The methods used included: use of high-speed, 2D cinematographic procedures to record the performances of 36 subjects (19 experts and 17 novices), determination of the kinematic and kinetic differences between the groups, and identification of a rationale describing how those kinematic differences could lead to the kinetic differences. Kinematic factors so identified could influence performance and injury risk. In addition to the fact that experts were able to lift 79% more weight than the novices, the pertinent kinetic differences included the following: 1) the difference in peak force exerted while lowering the bar was only 43%; 2) the difference in peak force exerted while raising the bar was only 45%; and 3) the difference in minimum force exerted while raising the bar was 87%. There was no significant difference in torque required at the shoulder. The relevant kinematic differences were: 1) the expert group maintained a smaller bar speed while lowering the bar, 2) the expert group used a bar path closer to the shoulders; and 3) the expert group used a different sequence of bar movements. The roles of these kinematic factors in the bench press merit further investigation.
Article
The purpose was to compare untrained college men with trained collegiate women basketball and volleyball players in terms of absolute and relative upper and lower body strength. Absolute and relative strength comparisons were also made between the two groups of women athletes. Eighty subjects were included in each group. Relative strength was expressed per unit of weight, height, biacromium, and biiliac widths. It was hypothesized that while men are significantly stronger than trained women athletes, such differences may be removed once body size characteristics are controlled. MANOVA and MANCOVA were utilized to test hypotheses. Results indicate that untrained men have greater upper and lower body strength than trained women athletes in terms of both absolute and relative strength. Women basketball players have greater upper and lower body strength than women volley players. The two groups of women athletes are alike in terms of upper body absolute and relative strength.
Article
To the Editor: We read with interest the recent article of Cooper et al, in which they proposed hand-to-feet bioelectrical impedance analysis (BIA) as an accurate and very useful surrogate marker for total body water (TBW) in patients with end-stage renal failure (ESRF)1. Despite this assertion, the authors also acknowledged that a great variation existed between TBW assessed by BIA compared to the gold standard (deuterium oxide) technique (-10.9 to 8.4 L). This wide variation is in agreement with our very recent findings (unpublished data), in which we also found a significant discrepancy between TBW assessed by multifrequency BIA and deuterium oxide (-3.4 to 20.3 l) in 18 patients with hemodialysis, and that BIA tended to underestimate TBW.
Article
1. Skinfold thickness, body circumferences and body density were measured in samples of 308 and ninety-five adult men ranging in age from 18 to 61 years. 2. Using the sample of 308 men, multiple regression equations were calculated to estimate body density using either the quadratic or log form of the sum of skinfolds, in combination with age, waist and forearm circumference. 3. The multiple correlations for the equations exceeded 0.90 with standard errors of approximately +/-0.0073 g/ml. 4. The regression equations were cross validated on the second sample of ninety-five men. The correlations between predicted and laboratory-determined body density exceeded 0.90 with standard errors of approximately 0.0077 g/ml. 5. The regression equations were shown to be valid for adult men varying in age and fatness.
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