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Comparison of Muscle Force Production Using the Smith Machine and Free Weights for Bench Press and Squat Exercises
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.
... It is often debated whether performing squats with the barbell resting freely on the shoulders or using a Smith machine is preferable for leg muscle strength training. Current evidence indicates that when the squat is performed in a fixed vertical movement path, greater absolute loads can be lifted (1,8). Schwanbeck et al. observed less gastrocnemius, biceps femoris and vastus medialis activation for Smith machine squats compared with a free movement path among six healthy individuals with strength training experience when using a load equivalent to their eight-repetition maximum (1). ...
... Another reason may be that the same absolute load was used for both conditions for standardization purposes. Previous research has found that performing squats in a Smith machine results in greater one repetition maximum (1RM) loads compared to free weight squats (8). This may subsequently lead to a lower relative load in relation to 1RM when squatting in the Smith machine with the same absolute weight as with a barbell resting freely on the shoulders, and therefore lower muscle activation. ...
... The potential influence of friction from the Smith machine was not considered in our study. Such friction is however considered minimal and was believed unlikely to influence our results (8). Further research is also needed to investigate whether altering stance (e.g., positioning of the feet) and squatting depths influences muscle activation between the two barbell conditions. ...
Introduction
Traditional recordings of muscle activation often involve time-consuming application of surface electrodes affixed to the skin in laboratory environments. The development of textile electromyography (EMG) electrodes now allows fast and unobtrusive assessment of muscle activation in ecologically valid environments. In this study, textile EMG shorts were used to assess whether performing squats with the barbell resting freely on the shoulders or using a Smith machine for a fixed barbell movement path is preferable for maximizing lower limb muscle activation.
Methods
Sixteen athletes performed free and fixed barbell squats in a gym with external loads equivalent to their body mass. Quadriceps, hamstrings and gluteus maximus activation was measured bilaterally with textile EMG electrodes embedded in shorts.
Results
Mean quadriceps activation was greater for the free compared with the fixed movement path for the right (mean difference [MD] 14μV, p = 0.04, η p ² = 0.28) and left leg (MD 15μV, p = 0.01, η p ² = 0.39) over the entire squat and specifically during the first half of the eccentric phase for the left leg (MD 7μV, p = 0.04, d = 0.56), second half of the eccentric phase for both legs (right leg MD 21μV, p = 0.05, d = 0.54; left leg MD 23μV, p = 0.04, d = 0.52) and the first half of the concentric phase for both legs (right leg MD 24μV, p = 0.04, d = 0.56; left leg MD 15μV, p = 0.01, d = 0.72). Greater hamstrings activation for the free path was seen for the second half of the eccentric phase (left leg MD 4μV, p = 0.03, d = 0.58) and first half of the concentric phase (right leg MD 5μV, p = 0.02, d = 0.72). No significant differences were found for gluteus maximus.
Discussion
Textile EMG electrodes embedded in shorts revealed that to maximize thigh muscle activity during loaded squats, a free barbell movement path is preferable to a fixed barbell movement path.
... 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. ...
... 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. ...
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.
... 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]. ...
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.
... Some studies have noted significantly greater increases in 1RM when utilizing FW compared to MW [14-16], while others have found MW to produce a greater increase than FW [17][18][19]. Yet other studies have found no modality difference in strength improvement following RT [20][21][22][23]. Greater neural activation of prime movers is typically observed during FW lifts than during equivalent loading with MW, which could explain some of the difference between lifting performances [9][10][11][12]. ...
... It should be noted that previous studies comparing FW and MW have found differing results. An early study by Stone, Johnson, and Carter [23] observed FW 1RM squats to be significantly greater than Universal machine squats in men in a beginning RT class. Additional research comparing FW and MW bench press training in a group of untrained women found a non-significantly higher 1RM for MW bench press compared to FW bench press [22]. ...
... Further, in contrast to BPT using the Smith machine, free-weight BPT could have provided a more "natural" throwing technique. 33 However, it can be assumed that safety in the present study was enhanced during exercise due to the restricted movement (ie, using the Smith machine). 33 Additionally, a recent systematic review indicated that variation in measures such as movement velocity was less when using a Smith machine. ...
... 33 However, it can be assumed that safety in the present study was enhanced during exercise due to the restricted movement (ie, using the Smith machine). 33 Additionally, a recent systematic review indicated that variation in measures such as movement velocity was less when using a Smith machine. 34 In support of this notion and with respect to the excellent reliability of the linear encoder used in the present study for assessing average velocity and vertical displacement (ie, r = .993), ...
Purpose : Power output is dependent on the load used during exercise such as bench-press throw (BPT). Attentional focus (external [EXT] vs internal [INT]) during exercise significantly modulates power performance. The purpose of the present study was to examine the effects of load and attentional focus on mechanical parameters during BPT. Methods : In a crossover study, 31 resistance-trained men (mean age 23.5 [3.0] y) performed BPT at 30% (light), 50% (moderate), and 70% (heavy) of 1-repetition maximum (1-RM) using an INT or EXT focus of attention in randomized order. A linear encoder was used to identify barbell vertical displacement, throw time, peak/average velocity, force, and power during the concentric lifting phase. Results : Statistical analysis revealed significant load × focus interaction effects for velocity and vertical displacement ( P ≤ .045; 0.66 ≤ d ≤ 0.89). Post hoc analyses indicated significantly larger velocities and displacements at 30% and 70% of 1-RM in favor of EXT ( P ≤ .038; 0.79 ≤ d ≤ 1.13) but similar values at 50% of 1-RM ( P > .05). Furthermore, significant main effects of load were found for throw time, force, and power ( P < .001; 4.20 ≤ d ≤ 14.0). While time and force gradually increased with higher loads ( P < .001; 1.45 ≤ d ≤ 14.0), power output was larger at 50% compared with 30% and 70% 1-RM ( P < .001; 3.09 ≤ d ≤ 7.07), irrespective of attentional focus. Conclusions : The present findings indicated that practitioners may use EXT over INT attentional focus to enhance velocity and vertical displacement during BPT at light and heavy loads (ie, 30% and 70% 1-RM). At moderate loads (ie, 50% 1-RM), mechanical bench-press parameters appear to be less affected by attentional focus.
... When performing bench press exercises, several methods have been adopted to create instability. First, compared to a Smith machine bench press lifting the bar in a fixed path, the free weight bench press may offer instability in all three planes of motion, which force the lifter to contract the muscles in a more natural fashion to keep balance while exerting force at an inconsistent velocity (Cotterman et al., 2005;Schick et al., 2010). Moreover, instability could be further increased by using a specially designed flexible barbell (e.g., Bandbell bar, "Earthquake" bar, or multi-grip Swiss Bar), suspending the load from a barbell through the use of elastic bands as well as completing the bench press on an unstable surface (Saeterbakken and Fimland, 2013;Dunnick et al., 2015;Ostrowski et al., 2017;Costello, 2020). ...
... Moreover, instability could be further increased by using a specially designed flexible barbell (e.g., Bandbell bar, "Earthquake" bar, or multi-grip Swiss Bar), suspending the load from a barbell through the use of elastic bands as well as completing the bench press on an unstable surface (Saeterbakken and Fimland, 2013;Dunnick et al., 2015;Ostrowski et al., 2017;Costello, 2020). In previous studies, the differences in muscle activation (as reflected by EMG amplitude) between a Smith machine and free weight bench presses and between free weight and increased instability bench press have been compared and revealed (Cotterman et al., 2005;Schick et al., 2010;Dunnick et al., 2015;Saeterbakken et al., 2016). As the instability degree from a Smith machine to free weight and to increased instability bench press increases gradually, muscle activation during the three bench presses may differ due to the change in instability degree. ...
The aim of this study was to analyze and compare the muscle activation and concomitant intermuscular coupling of antagonist muscles among bench presses with different instability degrees. Twenty-nine untrained male college students performed bench press exercises at an intensity of 60% 1 RM on three conditions: small unstable bench press with Smith machine (SBP), medium unstable bench press of free weight (FWBP), and large unstable bench press with increased instability by suspending the load with elastic bands (IIBP). One-way repeated measures analysis of variance was used to compare integrated EMG activity values of the biceps brachii (BB), posterior deltoid (PD), long head of the triceps brachii (TB), anterior deltoid (AD), upper portion of the pectoralis major (PM) muscles, and phase synchronization index (PSI) of BB-TB and PD-AD antagonist muscle pairs. A higher integrated EMG of BB muscle was found during bench press with a more unstable condition. IIBP showed a higher integrated EMG of prime movers (TB, AD, and PM) and stabilizing of BB than SBP and FWBP. PSI between muscle pairs of BB-TB in the gamma frequency band was higher in SBP than the other bench presses with unstable conditions, which may be related to the optimal “internal model” for antagonist muscles during bench press exercise. Therefore, IIBP training may be an effective accessory exercise to maintain a higher level of muscle activation across primary and stabilizing muscles with a lighter load for untrained men, while SBP may be a suitable bench press exercise for untrained participants who have not developed the neuromuscular adaptations necessary for correct stabilization of the elbow joint.
... 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. ...
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.
... 4 Isotonic exercises encourage a natural pattern of movement, requiring muscle coordination and joint stability in all planes of movement, so strength gains can be transferred more easily to the playing fields. 7 Considering these effects, we believe that biofeedback exercises combined with isotonic contractions will provide more benefits for the development of the muscle strength and proprioception. It is thought that biofeedback exercises involving isotonic contractions performed with the mode of the isokinetic dynamometer will improve proprioception by stimulating muscle spindle 8 better than EMG biofeedback exercises that include isometric contraction. ...
... 4 Gli esercizi isotonici incoraggiano un modello naturale di movimento, richiedendo coordinazione muscolare e stabilità articolare in tutti i piani di movimento, ergo i guadagni di forza possono essere trasferiti più facilmente ad analoghe situazioni di gara. 7 Considerando questi effetti, crediamo che gli esercizi di biofeedback combinati con contrazioni isotoniche siano in grado di fornire maggiori benefici per lo sviluppo della forza muscolare e della propriocezione. Riteniamo inoltre che gli esercizi di biofeedback con contrazioni isotoniche eseguiti con l'ausilio della specifica modalità di un dinamometro isocinetico possano migliorare la propriocezione stimolando il fuso neuromuscolare 8 più efficacemente rispetto agli esercizi di biofeedback EMG che includono la contrazione isometrica. ...
SUMMARY
BACKGROUND: Biofeedback exercises are among the frequently used methods to increase muscle strength and pro�prioception. However, no previous study investigating the effects of exercises performed with the biofeedback mode of an isokinetic dynamometer on muscle strength, proprioception and balance, could be traced. The aim of the study was to explore the effects of exercises performed in the biofeedback mode of an isokinetic dynamometer with their isotonic counterparts on muscle strength, balance, and proprioception.
METHODS: Ninety-five participants were included in this prospective case control study. Isometric and isokinetic muscle strength test, biofeedback test, Y-balance test, active and passive proprioception measurements of the study participants were performed. Three experimental groups (IT-IT group: isotonic exercises, IT-BF group: isotonic and bi�ofeedback exercises, BF-BF group: biofeedback exercises) were made to perform 10 sessions of exercises (IT-IT group: 3×10 repetition, 2 sets isotonic exercises; IT-BF group: 3×10 repetition isotonic exercises and 3×60 sec biofeedback exercises; BF-BF group: 3×60 sec 2 sets biofeedback exercises/strength [50% MVC for the quadriceps muscle with the help of an isokinetic dynamometer]). No intervention was performed in the control group.
RESULTS: After the exercise program in all groups to which the exercise protocol was applied, a statistically significant improvement was found in quadriceps strength, balance, and proprioception results (P<0.05). The Y-balance test and proprioception final measurement of the BF-BF group were significantly higher compared to the other three groups (IT-IT group, IT-BF group and control group), and the most significant improvement was observed in the BF-BF group (P<0.05).
CONCLUSIONS: The exercise performed in the biofeedback mode of an isokinetic dynamometer made significant contributions to the simultaneous improvement in the three parameters of physical fitness. Based on all these data, exercises performed in the biofeedback mode are possibly superior to conventional isotonic exercise practices.
(Cite this article as: Oğul A, Ercan S, Çetın C, Canbulut A, Ergan M, Acar HT, et al. The effect of biofeedback exercises for the quadriceps muscle on the muscle strength, balance, and proprioception. Med Sport 2022;75:29-44. DOI: 10.23736/S0025-7826.22.03894-7)
Key words: Biofeedback; Psychology; Muscle strength; Quadriceps muscle; Proprioception.
RIASSUNTO
OBIETTIVO: Gli esercizi di biofeedback sono tra i metodi più frequentemente impiegati per aumentare la forza muscolare e la propriocezione. Tuttavia, non è stato possibile rintracciare in letteratura alcuno studio che indaghi gli effetti sulla forza muscolare, sulla propriocezione e sull’equilibrio di tali esercizi, eseguiti con la modalità biofeedback di un dinamometro isocinetico. Lo scopo del presente studio è stato quello di esplorare gli effetti degli esercizi eseguiti usufruendo della modalità biofeedback di un dinamometro isocinetico sulla forza muscolare, sull’equilibrio e sulla propriocezione, rispetto alle controparti isotoniche.
METODI: Novantacinque partecipanti sono stati inclusi in questo studio prospettico caso-controllo. I partecipanti studio sono stati sottoposti a test di forza muscolare isometrica e isocinetica, test di biofeedback, Y-balance test per misurare l’equilibrio e misurazioni di propriocezione attiva e passiva. Tre gruppi sperimentali (gruppo IT-IT: esercizi isotonici; gruppo IT-BF: esercizi isotonici e biofeedback; gruppo BF-BF: esercizi di biofeedback) hanno svolto 10 ses�sioni di esercizi (gruppo IT-IT: 3×10 ripetizioni, 2 serie di esercizi isotonici; gruppo IT-BF: 3×10 ripetizioni di esercizi isotonici e 3×60 sec esercizi di biofeedback; gruppo BF-BF: 3×60 sec 2 serie di esercizi di biofeedback/forza [50% MVC per il muscolo quadricipite con l’aiuto di un dinamometro isocinetico]). Nessun intervento è stato eseguito nel
gruppo di controllo.
RISULTATI: In tutti i gruppi a cui è stato applicato il protocollo di allenamento, è stato riscontrato un miglioramento statisticamente significativo nei risultati di forza dei quadricipiti, equilibrio e propriocezione (P<0,05), successivamen�te all’allenamento. L’Y-balance test e la misurazione finale della propriocezione del gruppo BF-BF hanno prodotto valori significativamente più elevati rispetto agli altri tre gruppi (gruppo IT-IT, gruppo IT-BF e gruppo di controllo), e il
miglioramento più significativo è stato osservato nel gruppo BF-BF (P<0,05).
CONCLUSIONI: L’esercizio eseguito usufruendo della modalità biofeedback di un dinamometro isocinetico ha contri�buito significativamente al miglioramento simultaneo dei tre parametri della forma fisica da noi monitorati. Sulla base dei dati raccolti durante lo studio, possiamo dedurre che gli esercizi eseguiti in modalità biofeedback sono probabil�mente da considerarsi superiori alle pratiche di esercizio isotonico convenzionali.
Parole chiave: Biofeedback; Psicologia; Forza muscolare; Muscolo quadricipite; Propriocezione.
... 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. ...
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
... 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). ...
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.
... 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]. ...
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.
... 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. ...
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.
... 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. ...
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.
... 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. ...
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.
... Although Smith machines serve a specific purpose and are often used in general health and fitness settings, they are not commonly used in S&C contexts or often located in such facilities, thus limiting transferability of Smithmachine-based data to free-weight exercises. In addition, coaches must refrain from cross-comparisons between Smith machines and freeweight data as peak velocity, maximum load lifted, and electromyographical muscle activity have been reported to differ between the 2 methods (17,89,100). Finally, LVPs are specific to exercise and sex, meaning that superfluous research studies in 1 exercise (e.g., bench press) limit transferability to other, more commonly used, exercises within typical S&C programs such as the back squat, deadlift, and weightlifting derivatives ( Table 2). ...
Velocity-based training (VBT) uses the measurement of velocity to help inform and influence testing, monitoring, programming, autoregulation, and feedback strategies within strength and conditioning (S&C) practice. This review focuses specifically on the definitions and underpinning principles of VBT, as well as load-velocity profiling, while undertaking an in-depth evaluation of the literature and translating this information into practical recommendations for S&C coaches. There is a detailed evaluation of the different ways to construct a load-velocity profile (LVP), providing examples of simplicity, time efficiency, increased accuracy, and optimizing training prescriptions and manipulations. New approaches, such as combining ballistic and nonballistic exercises, and methods of extrapolation have been explored. In addition, this review highlights practical considerations regarding data analysis, specific exercises, statistical modeling, number of loads, and extrapolation methods. A worked example of using LVP data within Excel has also been presented. Finally, there is a focus on 1 repetition maximum prediction, the benefits and challenges of implementing such an approach, and the most appropriate ways of collecting reliable and valid data.
... This corroborates the findings of recent studies, in which muscle electrical activity was analyzed in exercises such as the SLP, the leg press at 45 • , and the squat, finding that they all activate the same major muscle groups, despite their differences in execution, as they are all lower limb press exercises [1,11,14]. Furthermore, as all exercises are performed on stable, guided machines, the core musculature may be more involved, as they rely less on the stabilizing musculature, as compared to exercises with free weights [41] Therefore, it is possible to proceed to the comparison of the machines with each other. ...
Featured Application
The main practical application of this research is the presentation of a new type of outdoor fitness equipment (OFE) available to both trainers and users, with scientific support regarding its ability to recruit the desired muscles in a similar way to conventional gym machinery. In addition, it was possible to improve the effectiveness of the OFE by including an intensity regulation system, thus allowing the principle of intensity progression to be considered, as well as increasing the control of training intensity in this type of machinery.
Abstract
This study compares the electromyographic activity (EMG) of different muscle groups (rectus femoris, vastus lateralis, biceps femoris, tibialis anterior, and gastrocnemius) of the lower limbs when performing a traditional seated leg press (SLP) with a classic piece of outdoor fitness equipment (OFE-SLP), and with a new OFE leg press that allows the user to adjust the intensity of the exercise by means of a selectorized system (BIOFIT-LP). It was found that the EMG of the OFE-SLP was significantly lower than that of the SLP, but similar activations to those of the SLP were achieved with the BIOFIT-LP. In conclusion, the inclusion of a system to be able to change intensity of the exercise in OFE achieves an EMG activity similar to traditional machinery in trained young men.
... For instance, exercises using the stretchshortening cycle produce greater amounts of force, velocity, and power than those incorporating a pause between eccentric and concentric contraction (6). In addition, although performing exercise on a Smith machine only involves vertical displacement of the bar, this is not the case for free-weight lifts (typically accompanied by some degree of horizontal displacement) (9). Therefore, approaches designed to estimate 1RM under a specific circumstance should not be used across dissimilar exercises or execution techniques. ...
Fitas, A, Santos, P, Gomes, M, Pezarat-Correia, P, Schoenfeld, BJ, and Mendonca, GV. Prediction of one repetition maximum in free-weight back squat using a mixed approach: the combination of the individual load-velocity profile and generalized equations. J Strength Cond Res XX(X): 000–000, 2023—We aimed to develop a mixed methods approach for 1 repetition maximum (1RM) prediction based on the development of generalized equations and the individual load-velocity profile (LVP), and to explore the validity of such equations for 1RM prediction. Fifty-seven young men volunteered to participate. The submaximal load-velocity relationship was obtained for the free-weight parallel back squat. The estimated load at 0 velocity (LD0) was used as a single predictor, and in combination with the slope of the individual LVP, to develop equations predictive of 1RM. Prediction accuracy was determined through the mean absolute percent error and Bland-Altman plots. LD0 was predictive of 1RM ( p < 0.0001), explaining 70.2% of its variance. Adding the slope of the LVP to the model increased the prediction power of 1RM to 84.4% ( p < 0.0001). The absolute percent error between actual and predicted 1RM was lower for the predictions combining LD0 and slope (6.9 vs. 9.6%). The mean difference between actual and estimated 1RM was nearly zero and showed heteroscedasticity for the LD0 model, but not for the combined model. The limits of agreement error were of 31.9 and 23.5 kg for LD0 and LD0 combined with slope, respectively. In conclusion, the slope of the individual LVP adds predictive value to LD0 in 1RM estimation on a group level and avoids error trends in the estimation of 1RM over the entire spectrum of muscle strength. However, the use of mixed methods does not reach acceptable accuracy for 1RM prediction of the free-weight back squat on an individual basis.
... Supporting our second hypothesis, the MV fastest associated with each RTF was greater for the Smith machine PBP compared to the free-weight PBP. This may be explained because machine-based equipment requires less inter-muscular coordination contributing to generate more force in the direction of the movement [9,10,21,22]. Consequently, the loads associated with the same MV fastest were higher for the Smith machine PBP and the higher loads could explain the lower RTFs for the same MV fastest . However, contrary to our second hypothesis, the MV fastest associated with each RTF was greater for the multiple-point method compared to the two-point method. ...
This study compared the accuracy of the fastest mean velocity from set (MVfastest) to predict the maximum number of repetitions to failure (RTF) between 2 variants of prone bench pull (PBP) exercise (Smith machine and free-weight) and 3 methods (generalized, individualized multiple-point, and individualized 2-point). Twenty-three resistance-trained males randomly performed 2 sessions during Smith machine PBP and 2 sessions during free-weight PBP in different weeks. The first weekly session determined the RTF-MVfastest relationships and subjects completed single sets of repetitions to failure against 60-70-80-90%1RM. The second weekly session explored the accuracy of RTFs prediction under fatigue conditions and subjects completed 2 sets of 65%1RM and 2 sets of 85%1RM with 2 min of rest. The MVfastest associated with RTFs from 1 to 15 were greater for Smith machine compared to free-weight PBP (F ≥ 42.9; P < 0.001) and for multiple-point compared to 2-point method (F ≥ 4.6; P ≤ 0.043). The errors when predicting RTFs did not differ between methods and PBP variants, whereas all RTF-MVfastest relationships overestimated the RTF under fatigue conditions. These results suggest that RTF–MVfastest relationships present similar accuracy during Smith machine and free-weight PBP exercises and it should be constructed under similar training conditions.
... There has been observed a higher maximum load lifted with machine-based exercises compared to free-weights within a similar exercise or movement. For example, some researchers have shown that more loads can be lifted with a Smith machine squat compared to a freeweight squat [14,17]. This could be affected by stability and/or bar path. ...
Background
The effectiveness of strength training with free-weight vs. machine equipment is heavily debated. Thus, the purpose of this meta-analysis was to summarize the data on the effect of free-weight versus machine-based strength training on maximal strength, jump height and hypertrophy.
Methods
The review was conducted in accordance with the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, and the systematic search of literature was conducted up to January 1st, 2023. Studies that directly compared free-weight vs. machine-based strength training for a minimum of 6 weeks in adults (18–60 yrs.) were included.
Results
Thirteen studies (outcomes: maximal strength [n = 12], jump performance [n = 5], muscle hypertrophy [n = 5]) with a total sample of 1016 participants (789 men, 219 women) were included. Strength in free-weight tests increased significantly more with free-weight training than with machines (SMD: -0.210, CI: -0.391, -0.029, p = 0.023), while strength in machine-based tests tended to increase more with machine training than with free-weights (SMD: 0.291, CI: -0.017, 0.600, p = 0.064). However, no differences were found between modalities in direct comparison (free-weight strength vs. machine strength) for dynamic strength (SMD: 0.084, CI: -0.106, 0.273, p = 0.387), isometric strength (SMD: -0.079, CI: -0.432, 0.273, p = 0.660), countermovement jump (SMD: -0.209, CI: -0.597, 0.179, p = 0.290) and hypertrophy (SMD: -0.055, CI: -0.397, 0.287, p = 0.751).
Conclusion
No differences were detected in the direct comparison of strength, jump performance and muscle hypertrophy. Current body of evidence indicates that strength changes are specific to the training modality, and the choice between free-weights and machines are down to individual preferences and goals.
... That is, the bar patch was fixed throughout the movements. Free-weight exercises possess other kinetic and kinematic movement characteristics, as there is typically more movement in the sagittal plane and higher range of motion when using free-weights [38]. Although caution is warranted when generalizing the present findings to free-weight movements, Loturco et al. [16] reported that both free-weights and Smith Machine could predict 1RM bench press with similar accuracy in top-level athletes. ...
Objectives
The purpose of this study was to explore the validity and reliability of three different strength testing approaches to determine one-repetition maximum (1RM) in the bench press and prone bench pull.
Methods
Twenty-eight recreationally active subjects (25 ± 2 years, 178 ± 8 cm, 78 ± 9 kg) were assessed for load-velocity (L-V) relationship, 1RM, maximal isometric force (MIF), and maximal repetitions to failure (MRF) in a Smith Machine on three separated sessions. Linear regression was used for L-V relationship, MIF, and MRF to predict 1RM. Level of significance was set to ρ ≤ 0.05.
Results
Reliability analyses of the varying 1RM estimations revealed mean differences from 0.6 to -1.3 kg (mainly trivial effects) between test days 1 and 2, intraclass correlation coefficient was > 0.96, and coefficient of variation (CV) was in the range 2.3–8.3% for all tests. Regarding validity, all 1RM predictions exhibited a mean difference ≤ 1.3 kg (trivial), except for the L-V relationship method that underestimated the predicted 1RM by 5 kg (small) compared to the actual bench press 1RM. However, the L-V relationship method showed the least mean absolute errors. CVs were in the range 4.5–13.2%. Standard error of the estimate was in the range 3.2–9.7 kg. Change scores for all tests were significantly correlated with change scores in actual 1RM, except for MIF in the prone bench pull. Smallest deviations in 1RM predictions were observed for the L-V relationship approach.
Conclusions
All 1RM prediction methods were highly comparable to the traditional 1RM test. However, given the high variability associated with individual predictions for each method, they cannot be used interchangeably.
... Although these findings are useful, it is not clear whether the results are ecologically valid to free-weight exercises utilising the stretch-shortening cycle that involve vertical and horizontal barbell movements (Cotterman et al. 2005). Free-weight exercises utilising the stretch-shortening cycle are more popular among trainees, especially athletes, and have been shown to have a greater transfer of training effects to sports performance compared with concentric-only contractions, particularly in more complex multi-joint exercises (Bobbert et al. 1996;Stone et al. 2002). ...
Purpose
The aim of this study was to examine the goodness of fit, prediction accuracy, and stability of general and individual relationships between velocity loss and the percentage of completed repetitions out of maximum possible (VL-% repetitions ) in the free-weight back squat exercise. The effects of sex, training status and history, as well as personality traits, on the goodness of fit and the accuracy of these relationships were also investigated.
Methods
Forty-six resistance-trained people (15 females and 31 males) performed a one-repetition maximum (1RM) test, and two repetitions to failure (RTF) tests, 72 h apart. RTF tests were performed with 70, 80, and 90% of 1RM with 10 min inter-set rest.
Results
The findings question the utility of using general and individual VL-% repetitions relationships to prescribe training volume with free-weight back squats as (1) the agreement in the % repetitions completed until reaching a given velocity loss threshold across two consecutive testing sessions was unacceptable, regardless of the load used; and (2) the ability of general and individual VL-% repetitions relationships to predict % repetitions in a subsequent testing session were poor (absolute errors > 10%). Sex, training status and history, and personality traits did not affect the goodness of fit of general and individual VL-% repetitions relationships or their prediction accuracy, suggesting potential generalisability of those findings among resistance-trained populations.
Conclusions
VL-% repetitions relationships do not seem to provide any additional benefits compared to costless, traditional methods and hence should not be used for monitoring and prescribing resistance training with a free-weight back squat exercise.
... Bu motorik özelliği geliştirmek isteyen antrenörler hem serbest ağırlıkları hem de kondisyon makinelerini sporcuların kuvvet, güç ve performansını geliştirmek için kullanılmaktadır. Kondisyon makineleri ile tek eklemli (sadece bir eklem içeren) ve serbest ağırlıklar kullanılarak yapılan çok eklemli güçlendirme antrenmanları, sporcunun fiziksel gelişimini kolaylaştıran genel aktivitelerdir 4 . Kuvvet antrenmanlarının hedefi, kasların içerisinde olan lif boyutlarında artış meydana getirerek gelişimlerini sağlamaktır 5 . ...
Bu çalışmanın amacı, geleneksel kuvvet antrenmanlarına karşın dirençli güç interval antrenman protokolünün ivmelenme, çeviklik ve hareket hızına etkisinin değerlendirilmesidir. Bu amaç doğrultusunda, lisanslı sporcu olmayan 20 genç gönüllü olarak katılım sağlamıştır. Katılımcılar, A grubu (AG, n=10, yaş: 21,3 yıl ± 1,41; boy: 176,4 cm. ± 4,69; kilo: 68,9 kg ± 5,6) ve B grubu (BG, n=10 yaş: 20,8 yıl ± 1,03; boy: 173,7 cm ± 6,63; kilo: 63,5 kg ± 5,9) olarak iki homojen gruba ayrılmıştır. Çalışmadan önce katılımcılara 2 hafta adaptasyon antrenmanı yaptırılmıştır. Bir tekrarlı maksimal kuvvet, tam squat hareketinde itme evresindeki hareket hızı, ivmelenme ve çeviklik testleri yaptırılmıştır. A Grubuna 6 haftalık geleneksel kuvvet antrenmanları (GKA), B Grubuna dirençli güç interval antrenmanları (DGİA) uygulanmıştır. Ara testler sonrasında antrenman protokolleri gruplar arasında çaprazlama değiştirilerek A Grubu DGİA, B Grubu ise GKA olarak 6 hafta devam ettirilmiştir. Ardından son testler yaptırılmıştır. Veriler SPSS 20 paket programında analiz edilmiştir (p0.05). Sonuç olarak; her iki antrenman protokolünün de performans parametrelerini geliştirdiği ve protokoller arasında anlamlı bir farklılık olmadığı elde edilmiştir. Ayrıca, belirtilen performans parametrelerini geliştirmek için her iki protokolün de kullanılabileceği ileri sürülebilir.
... Kinesiotaping has been studied in both research and clinical practise, particularly in terms of its impacts on speed, target, accuracy, and proprioception; nevertheless, the results are still inconclusive. It is vital to note that the glenohumeral joint is linked to scapular stabiliser muscle imbalance, therefore kinesiotaping may be useful in correcting position alterations and scapular movement, thereby reducing instability (Cotterman et al., 2005). The purpose of the study was to compare the combined effect of kinesiotaping with 'ballistic six plyometric training' and with ballistic six plyometric training alone on speed, accuracy, target and joint proprioception in fast bowlers with mild glenohumeral joint instability. ...
Cricket is one of the most popular international sports played worldwide. Ballistic six plyometric training improves throwing activity in throwing sports, improves rotator cuff muscular strength, and prevents and reduces the risk of shoulder injury associated with overhead pitching. Kinesiotaping is used in rehabilitation, as a treatment for sportsrelated injuries, and as a means of injury prevention.
The objective of the study was to compare the combined effect of kinesiotaping with ‘ballistic six plyometric training’ and with ballistic six plyometric training alone on speed, accuracy, target and joint proprioception in fast bowlers with mild glenohumeral joint instability.
Thirty male semiprofessional fast bowlers in the age group of 20-30 years were included in this study and randomly divided into two groups: group A and group B with 15 players in each group. Group A received kinesiotaping along with ballistic six plyometric training, whereas group B was only given ballistic six plyometric training. Both groups also performed conventional upper extremity workouts. All players were evaluated for bowling speed, accuracy, target and joint proprioception (internal rotation & external rotation) with a radar gun, cricket specific bowling accuracy test, no. of balls hit stump in an over and inclinometer, respectively.
Both groups improved significantly at the end of week 8, however, group B showed significant difference for bowling speed, accuracy, target and joint proprioception (P<0.05). Rehabilitation protocol comprising of combined kinesiotaping, plyometrics along with conventional protocol can be beneficial in enhancing performance related variables, i.e. bowling speed, accuracy and target in fast bowlers with mild glenohumeral instability.
... Barbell squatting movements, for instance, are complex free-weight exercises with many potential kinematic sources of variation (e.g., spine, ankle, knee and/or hip) [49]. When performed on a Smith machine, the reduced balance demands are theorised to contribute to a greater squat 1RM (i.e., 3.7%) when compared to free-weight squat 1RM (Smith machine: 129.0 kg, free-weight: 124.3 kg) [50]. This is despite greater electromyographic activity of the vastus medialis (49%), gastrocnemius (34%) and biceps femoris (26%) is observed during freeweight squats when compared to Smith machine squats [51]. ...
Maximal strength can be predicted from the load-velocity relationship (LVR), although it is important to understand methodological approaches which ensure the validity and reliability of these strength predictions. The aim of this systematic review was to determine factors which influence the validity of maximal strength predictions from the LVR, and secondarily to highlight the effects of these factors on the reliability of predictions. A search strategy was developed and implemented in PubMed, Scopus, Web of Science and CINAHL databases. Rayyan software was used to screen titles, abstracts, and full texts to determine their inclusion/eligibility. Eligible studies compared direct assessments of one-repetition maximum (1RM) with predictions performed using the LVR and reported prediction validity. Validity was extracted and represented graphically via effect size forest plots. Twenty-five eligible studies were included and comprised of a total of 842 participants, three different 1RM prediction methods, 16 different exercises, and 12 different velocity monitoring devices. Four primary factors appear relevant to the efficacy of predicting 1RM: the number of loads used, the exercise examined, the velocity metric used, and the velocity monitoring device. Additionally, the specific loads, provision of velocity feedback, use of lifting straps and regression model used may require further consideration.
... Kinesiotaping has been studied in both research and clinical practise, particularly in terms of its impacts on speed, target, accuracy, and proprioception; nevertheless, the results are still inconclusive. It is vital to note that the glenohumeral joint is linked to scapular stabiliser muscle imbalance, therefore kinesiotaping may be useful in correcting position alterations and scapular movement, thereby reducing instability (Cotterman et al., 2005). The purpose of the study was to compare the combined effect of kinesiotaping with 'ballistic six plyometric training' and with ballistic six plyometric training alone on speed, accuracy, target and joint proprioception in fast bowlers with mild glenohumeral joint instability. ...
Cricket is one of the most popular international sports played worldwide. Ballistic six plyometric training improves throwing activity in throwing sports, improves rotator cuff muscular strength, and prevents and reduces the risk of shoulder injury associated with overhead pitching. Kinesiotaping is used in rehabilitation, as a treatment for sportsrelated injuries, and as a means of injury prevention. The objective of the study was to compare the combined effect of kinesiotaping with ‘ballistic six plyometric training’ and with ballistic six plyometric training alone on speed, accuracy, target and joint proprioception in fast bowlers with mild glenohumeral joint instability. Thirty male semiprofessional fast bowlers in the age group of 20-30 years were included in this study and randomly divided into two groups: group A and group B with 15 players in each group. Group A received kinesiotaping along with ballistic six plyometric training, whereas group B was only given ballistic six plyometric training. Both groups also performed conventional upper extremity workouts. All players were evaluated for bowling speed, accuracy, target and joint proprioception (internal rotation & external rotation) with a radar gun, cricket specific bowling accuracy test, no. of balls hit stump in an over and inclinometer, respectively. Both groups improved significantly at the end of week 8, however, group B showed significant difference for bowling speed, accuracy, target and joint proprioception (P<0.05). Rehabilitation protocol comprising of combined kinesiotaping, plyometrics along with conventional protocol can be beneficial in enhancing performance related variables, i.e. bowling speed, accuracy and target in fast bowlers with mild glenohumeral instability.
... 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. ...
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.
... 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. ...
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.
... 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). ...
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.
... 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). ...
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. ...
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.
... 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]. ...
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.
... 5 Additionally, 1RM can be up to 22% higher when using a free weight barbell compared to a smith machine which has been attributed to the smith machine's restriction of horizontal barbell motion that creates a fixed and constant moment arm throughout the lift. 6,7 Thus, horizontal barbell motion may also influence the potential to lift higher loads, but it is unknown if there is a difference in horizontal motion between using an arched and flat back technique. Previous evidence has demonstrated that changing spine motion can influence the motion of the extremities and vice versa. ...
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.
... 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. ...
BACKGROUND
Comparison of knee loads on a Smith machine, which is utilised 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% ([Formula: see text] 0.01; [Formula: see text] 1.58) and to 60% ([Formula: see text] 0.01; [Formula: see text] 1.37). Patellofemoral compressive ([Formula: see text] 0.96) and tibiofemoral shear forces ([Formula: see text] 0.55) were not influenced by external load or type of squat. Gluteus medius and minimus produced more force at 80% compared to 60% ([Formula: see text] 0.01; [Formula: see text] 1.10) and to 40% ([Formula: see text] 0.01; [Formula: see text] 1.87) without differences for other muscles ([Formula: see text] 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.
... 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). ...
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.
... 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). ...
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.
... 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. ...
Objective: The purpose of this study was to examine the effect of pre-fatiguing the triceps brachii on subsequent strength performance and myoelectric activity in the barbell, dumbbell, and Smith machine bench press. Method: Nineteen trained men participated of this study (27.9 ± 4.5 years; 1.72 ± 0.1 m; 80.3 ± 9.2 kg). Ten-repetition maximum loads were determined for the triceps extension as well as the barbell barbell, dumbbell and Smith machine bench press. Three experimental protocols were performed in a randomized design. All experimental protocols began with four sets of the triceps extension (performed with a high pulley) to repetition failure followed by four sets to repetition failure for one of three bench press modalities. Two minute-rest intervals were adopted between sets and exercises. Total repetitions (work), training volume and myoelectric activity of pectoralis major, anterior deltoid, biceps brachii, and triceps brachii were recorded during each bench press modality. Results: Significantly greater activity of the biceps brachii was observed during performance of the dumbbell bench press versus barbell and Smith machine bench press. No other significant differences were observed between protocols. Conclusion: Therefore, considering the training volume and myoelectric activity of the synergistic muscles, similar performance across bench press modalities can be expected when preceded by performance of a triceps extension.
... 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. ...
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.
... 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. ...
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.
... 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. ...
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.
... 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). ...
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.
... 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. ...
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.
The primary objective of the study was to compare the muscle electrical activity during Benchpress for the different muscle groups. The amount of contribution of each mentioned muscle duringbench press was also analyzed.For the purpose of the present investigation, total of 10 male power lifterswere chosen as the sample forthe study.The analysis showed that there is a significant difference in the muscle electrical activity during Benchpress for the different muscle groups. The results pertaining to EMG data of 1RM bench pressrevealed maximum muscle electrical activity in case of Pectoralis Major. Hence the Pectoralis Majordisplayed better muscle electrical activity than the Anterior deltoid and Triceps
This study compared the kinematics, surface electromyography (sEMG) and kinetics among isometric squats performed at 10 different heights of the upward part and a one-repetition maximum (1-RM) squat. Eleven males (age: 27.5 ± 3.4 years, body mass: 84.9 ± 8.1 kg, body height: 1.79 ± 0.06 m, 1-RM squat: 152.2 ± 20.55 kg) took part in this study. It was found that force output was lowest in the sticking region at around the event of peak deceleration for the 1-RM trial with force output at 2179 ± 212 N. For the isometric trial, the lowest force output occurred at the lowest barbell height (1735 ± 299 N). In addition, for the 1-RM condition hip extension moments peaked at the first four barbell heights (6.5–6.2 Nm/kg) representing the pre-sticking and the sticking region before significantly decreasing during the events representing the post-sticking region. Additionally, the sEMG amplitude peaked for the hip extensors at the barbell heights corresponding to the post-sticking region. Moreover, the sEMG amplitude was significantly higher for the 1-RM condition for all hip extensors, vastus lateralis, and calf muscles (F ≥ 2.7, p ≤ 0.01, ηp² ≥ 0.25). Therefore, we suggest that the sticking region occurs because of reduced force output in the pre-sticking and the sticking region in back squats among resistance-trained males. The reduced force output is probably a combination of suboptimal internal moment arms, length-tension relationships of the gluteus maximus, hamstring and vastii muscles in the pre-sticking and sticking regions to overcome the large extensor moments together with diminishing potentiation from the pre-sticking to the sticking region.
The objective of this study was to compare a number of variables derived from the vertical and horizontal force components between loaded countermovement jumps performed in a Smith machine (SM modality; vertically restrained jumps) and with free weights (FW modality; unrestrained jumps). Twenty-three recreationally trained individuals, 6 women and 17 men, performed on a 3D force platform 5 maximal countermovement jump trials against 3 external loads (30%, 50%, and 70% of the SM 1-repetition maximum) using the SM and FW jumping modalities on separate sessions. The SM modality promoted greater values for virtually all the variables derived from the vertical force component (maximal force, maximal and minimum velocity, and impulse) and also shorter durations of the braking and propulsive phases. Regardless of the countermovement jump phase (braking or propulsive), the impulse directed toward the backward direction was always considerably greater for the SM compared with the FW modality. These results evidence that for recreationally trained individuals, the SM modality could be more effective to increase the general force capacity of the leg muscles due to increased external stability, while the FW modality is preferable when the orientation of force application is a crucial consideration, as it reduces the horizontal force component.
This study investigated the grouped and individualized load-velocity profile (GLVP vs. ILVP) in Bulgarian split squat using Smith machine and free weight. Seventy five recreational male lifters completed two incremental loading tests of Bulgarian split squat. Mean velocity was measured by a linear-position transducer (GymAware). Linear regression equation was applied to construct the GLVP and ILVP. The agreement of predicted %1RM and measured %1RM was assessed by a combination of intraclass correlation coefficient (ICC), coefficient of variation (CV), standard error of measurement (SEM) and Bland-Altman analysis. Acceptable validity was defined as ICC > 0.75, CV ≤ 10% and p ≥ 0.05 (a paired Wilcoxon signed-rank test). A very high level of inverse load-velocity relationships were demonstrated in Bulgarian split squat (r = −0.92) with free weights and a Smith machine. ILVP (ICC ≥ 0.98, CV ≤ 8.73%, p ≥ 0.56) was valid enough to predict the %1RM, but GLVP of both limbs revealed large CVs in free weights (CV: 15.4%,15.63%) and a Smith machine (CV: 11.24%, 12.25%). Cross-validation between the actual %1RM and predicted %1RM using free weights and a Smith machine ILVP was not acceptable (p ≤ 0.03, CV ≥ 14.07%). A very high level of inverse relationship were observed between %1RM and MV in Bulgarian split squat using free weights and a Smith machine, indicating individualized load velocity properties, and the ILVP showed high between-devices variability in both scenarios. Using velocity as a measure of loading intensity in Bulgarian split squat needs to consider the individualized load velocity properties, and difference between free weights and a Smith machine.
Hernández-Belmonte, A, Buendía-Romero, Á, Pallares, JG, and Martínez-Cava, A. Velocity-based method in free-weight and machine-based training modalities: the degree of freedom matters. J Strength Cond Res XX(X): 000-000, 2023-This study aimed to analyze and compare the load-velocity relationships of free-weight and machine-based modalities of 4 resistance exercises. Moreover, we examined the influence of the subject's strength level on these load-velocity relationships. Fifty men completed a loading test in the free-weight and machine-based modalities of the bench press, full squat, shoulder press, and prone bench pull exercises. General and individual relationships between relative intensity (%1RM) and velocity variables were studied through the coefficient of determination (R2) and standard error of the estimate (SEE). Moreover, the velocity attained to each %1RM was compared between both modalities. Subjects were divided into stronger and weaker to study whether the subject's strength level influences the mean test (mean propulsive velocity [MPVTest]) and 1RM (MPV1RM) velocities. For both modalities, very close relationships (R2 ≥ 0.95) and reduced estimation errors were found when velocity was analyzed as a dependent (SEE ≤ 0.086 m·s-1) and independent (SEE ≤ 5.7% 1RM) variable concerning the %1RM. Fits were found to be higher (R2 ≥ 0.995) for individual load-velocity relationships. Concerning the between-modality comparison, the velocity attained at each intensity (from 30 to 100% 1RM) was significantly faster for the free-weight variant. Finally, nonsignificant differences were found when comparing MPVTest (differences ≤ 0.02 m·s-1) and MPV1RM (differences ≤ 0.01 m·s-1) between stronger and weaker subjects. These findings prove the accuracy and stability of the velocity-based method in the free-weight and machine-based variants but highlight the need to use the load-velocity relationship (preferably the individual one) specific to each training modality.
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.
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.
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.
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
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
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.
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.
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.
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.
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.
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
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.
This study investigated the muscular torques and joint forces during the parallel squat as performed by weightlifters. (JD)
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.
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.
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.
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.
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.
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
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.
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.
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.
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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