Article

Elastic Bands in Combination With Free Weights in Strength Training: Neuromuscular Effects

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Abstract

This study compared the effects of a variable- versus a constant lower limb resistance training program on muscle strength, muscle activation and ballistic muscle performance at different knee angles. Thirty-two females were randomized to a constant resistance training free-weight group (FWG) or a variable resistance training group, using free-weights in combination with elastic bands (EBG). Two variations of the squat exercise (back squat and split) were performed two days per week for ten weeks. Knee extensor maximal voluntary isometric contraction (MVC) and counter movement jump were assessed at knee angles of 60°, 90° and 120° before and after the intervention. During the MVCs, muscle activation of the superficial knee extensor muscles was measured using surface electromyography. The FWG increased their MVCs at 60° and 90° (24% and 15%, respectively) while the EBG only increased significantly at 60° (15%). The FWG increased their jump height significantly at all angles (12-16%) while the EBG only improved significantly at 60° and 90° (15% and 10%, respectively). Both groups improved their 6-RM free-weight squat performance (EBG: 25% and FWG: 23%). There were no significant changes in muscle activation. In conclusion, constant- and variable resistance training provided similar increases in dynamic and isometric strength, and ballistic muscle performance, albeit most consistently for the group training only with free-weights.

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... With the increase in research on VRT, contradictory research data have emerged. The results of several of studies have not found that VRT is better than CRT for the development of maximum strength [16,22,23]. In a study by Cronin et al. [24], participants performed supine jump squat training with a load of 8-15 repetition maximum (RM) with or without elastic bungees. ...
... A total of 22 reports that comprised both trained and untrained participants were included for the meta-analysis [8,16,[22][23][24][31][32][33][34][35][36][37][38][39]. As shown in Figure 2, VRT and CRT significantly differed in the improvement of the maximum strength of the subjects (ES = 0.80; 95% CI: 0.42-1.19). ...
... The meta-analysis conducted on the studies of only trained subjects showed that VRT favored a significantly higher improvement of maximum strength than CRT (ES = 0.57; 95% CI: 0.22-0.93; Figure 3) [8,[22][23][24]32,[36][37][38][39]. Based on the VRT workload, we then subgrouped the studies into <80% and ≥80% 1RM. ...
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Greater muscular strength is generally associated with superior sports performance, for example, in jumping, sprinting, and throwing. This meta-analysis aims to compare the effects of variable-resistance training (VRT) and constant-resistance training (CRT) on the maximum strength of trained and untrained subjects. PubMed, Web of Science, and Google Scholar were comprehensively searched to identify relevant studies published up to January 2022. Fourteen studies that met the inclusion criteria were used for the systematic review and meta-analysis. Data regarding training status, training modality, and type of outcome measure were extracted for the analyses. The Cochrane Collaboration tool was used to assess the risk of bias. The pooled outcome showed improved maximum strength with VRT, which was significantly higher than that with CRT (ES = 0.80; 95% CI: 0.42–1.19) for all the subjects. In addition, trained subjects experienced greater maximum-strength improvements with VRT than with CRT (ES = 0.57; 95% CI: 0.22–0.93). Based on subgroup analyses, maximum-strength improvement with a VRT load of ≥80% of 1 repetition maximum (1RM) was significantly higher than that with CRT (ES = 0.76; 95% CI: 0.37–1.16) in trained subjects, while no significant differences were found between VRT and CRT for maximum-strength improvement when the load was
... Furthermore, the findings with respect to power performance are also equivocal. Despite some studies supposing the superiority of VRT in terms of velocity-specific adaptation (Frost et al., 2010;Wallace et al., 2018), several studies have shown no significant differences between VRT and CRT (Andersen et al., 2015;Ataee et al., 2014;Katushabe and Kramer, 2020). The lack of powerful tasks within the intervention may result in the unchanged power outcomes. ...
... To ensure similar loading across both groups, half of the variable resistance (17% 1RM) was removed from the free-weight in the VRT group, as previously reported (Krčmár et al., 2021;Mina et al., 2019). In addition, when adjusting the intensity of the back squat throughout the intervention, the contribution of variable resistance remained constant and only the free-weight varied in the VRT group (Andersen et al., 2015). ...
... Our findings regarding the CMJ and SJ output showed significant within-group improvements in both groups. Our results concur with previous studies (Andersen et al., 2015;Joy et al., 2016;Katushabe and Kramer, 2020). Andersen et al. (2015) reported that VRT and CRT groups significantly increased the CMJ in two modes (starting depth of a 60° and a 90° knee angle) after a 10-week intervention with two sessions per week, whereas no significant difference was observed between groups. ...
Article
The aim of this study was to investigate the differences in neuromuscular performance between variable resistance training and constant resistance training within complex training. Twenty-one well-trained collegiate basketball players were randomly assigned to either an experimental group (variable resistance training) or a control group (constant resistance training) and completed a twice weekly training program over an 8-week period. Training programs were the same except that the experimental group included variable resistance via elastic bands (40% of the total load). Maximum strength, vertical jump, horizontal jump, and sprint performance were assessed pre-and post-intervention. Both groups demonstrated significant increases in the back squat 1RM (experimental group +36.5% and control group +32.3%, both p < 0.001), countermovement jump (experimental group +12.9%, p = 0.002 and control group +5.6%, p = 0.02), and squat jump performance (experimental group +21.4% and control group +12.9%, both p < 0.001), whereas standing broad jump performance improved only in the experimental group (+2.9%, p = 0.029). Additionally, the experimental group showed significant improvement in the squat jump (p = 0.014) compared with the control group. However, no statistically significant differences were found between groups for countermovement jump (p = 0.06) and sprint performance at 10 m (p = 0.153) and 20 m (p = 0.076). We may conclude that both training modalities showed similar improvements in maximum strength. Performing variable resistance training within a complex training program is more efficient to enhance selective power performance in well-trained collegiate basketball players.
... This procedure consists of performing between 8 and 12 maximal repetitions and introducing an elevation in IOP [1,2]. Given that the EB reduce the load throughout this biomechanically disadvantageous region of the movement [26] due to their elongation coefficient [25], the question arises whether the use of EB in resistance exercises could generate different responses in ocular parameters compared to conventional resistance (e.g., weight plates). ...
... Squatting with EB reduces the weight at the bottom phases of the squat, during which a mechanical disadvantage occurs [25,26]. Beyond this point, EB add progressively more resistance/weight until the end of the movement. ...
... Beyond this point, EB add progressively more resistance/weight until the end of the movement. Thus, exercising with EB can increase the load in the region of the range of motion that is more mechanically effective, accompanied by reduced loads in the less efficient range [22,25,26]. This feature of the EB allowed subjects to perform more repetitions, which is useful to promote muscle adaptations [16,27,57]. ...
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This study aimed to compare intraocular pressure (IOP), mean ocular perfusion pressure (MOPP) and central corneal thickness (CCT) acute adaptations to squat exercise using elastic bands (EB) or weight plates (WP) together with the weight of the bar and applying maximal or submaximal efforts. Cardiovascular parameters (pulse pressure, mean blood pressure, heart rate), rate of perceived exertion, kilograms, and number of repetitions served to monitor psychophysiological acute variations. Twenty physically active males (25.55 ± 4.75 y.o.) underwent two sessions (one for familiarization and one for the experimental trial). In the experimental session, ocular and cardiovascular pre-exercise measurements were taken. Then, two sets using WP and two using EB attached to the bar with the same load were performed by each subject in random order. Immediately after finishing each set, the subjects rated perceived exertion, and cardiovascular and ocular measurements were taken,in this order. An ANOVA with post-hoc LSD evaluated differences between sets. IOP significantly decreased (p < 0.001, ƞp² = 0.513), and MOPP (p < 0.001, ƞp² = 0.413) and cardiovascular variables significantly increased due to the exercise effect; CCT changes were non-significant. No significant effect of the material, level of effort, or their interaction was observed in the IOP and MOPP (p > 0.05). EB permitted more repetitions to be performed and led to non-significantly lower post-exercise IOP values (effect size [d] compared to resting 0.79 and 1.00) in comparison to WP (d = 0.73–0.74). IOP and ocular and systemic hemodynamic responses are similar when using EB instead of WP to load the bar, with EB allowing a larger number of repetitions. Data presented in this paper may help with the prescription of resistance training for people with glaucoma risk factors.
... Elastic Bands (EB) are increasing in popularity for strength training for both health and physical performance (Colado et al., 2010;2020;Colado and Triplett, 2008;Saeterbakken et al., 2014;Soria-Gila et al., 2015). EB have been shown to induce similar neuromuscular activation and adaptations to free weights and machines (Colado and Triplett, 2008;Colado et al., 2010;Sundstrup et al., 2012;Iversen et al., 2017), and provide optimal muscle stimulation across the entire range of motion for different resistance exercises such as the squat (Andersen et al., 2015;Joy et al., 2016). ...
... Nevertheless, most of the previous research has used EB with a lower tensile force or in combination with higher loads of constant resistance devices Andersen et al., 2015;Iversen et al., 2017). Only some studies are in line with our procedures and have used EB to achieve similar or even higher external resistance than the one used with constant resistance devices (Colado and Triplett, 2008;Colado et al., 2010;Andersen et al., 2016;Aboodarda et al., 2013). ...
... Regarding the load, obtained 5RM and 10RM (Table 1) are consistent with the percentages (Reynolds et al., 2006;Andersen et al., 2015) and kilograms (Joy et al., 2016) used by some studies with a varied subject population. On the other hand, some researches assessing free barbell squat reported lower average loads (Bryanton et al., 2012;Saeterbakken et al., 2016;Andersen et al., 2016;Iversen et al., 2017), and one study showed greater loads (Vigotsky et al., 2019). ...
Article
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Modifying basal elongation of elastic bands (EB) has been proven useful to increase some parameters of the intensity in variable resistance training. Therefore, the question arises as to whether the pertinent resistance could be applied with EB immediately above the sticking point in squat exercises to optimize the performance. The purpose was to analyze some variables of the external (kilograms and number of repetitions) and internal load (heart rate, blood pressure, and rate of perceived exertion) after six different conditions of the squat exercise when using weight plates (WP) or EB (placed at different points of the range of motion) and applying maximal or submaximal effort. Twenty physically active males (25.50 ± 5.26 yrs) underwent two sessions for familiarization and one for assessment. The six conditions (three with WP and three with EB) were randomly performed. The sticking point of each subject was measured using the knee joint angle and the resistance was applied with EB at this height. Immediately after finishing each set subjects reported perceived effort rate and cardiovascular measurements were taken. Repetitions completed, and kilograms used were recorded. Repeated measures testing evaluated differences between conditions. EB permitted performing 8 more repetitions compared to WP when the same load was added at standing position. Adding the load immediately above the sticking point significantly (p < 0.05) increased 24.7% the kilograms used and permitted participants to perform 3 more repetitions. Internal load measurements suggested that EB could significantly (p < 0.05) reduce the perceived effort rate and/or physiological stress depending on their application. EB are a suitable device to load the bar for squat exercises in fit young men. According to the necessities of the subjects, if the load with EB is added at different points of the range of motion, it could be possible to overcome the sticking point, to maximize the performance and/or modulate cardiovascular and perceptual responses.
... The squat depth was measured and controlled by placing a horizontal band behind the participants. They were instructed to touch the band lightly with their gluts before pressing upwards [31]. The height of the band corresponded to a 90˚angle of the knees. ...
... The participants used their preferred foot width. The distance between the heels and big toes of feet were measured and used in testing and training [31]. The participants maintained a natural sway in their lower back during the entire lift. ...
... Between 1-3 attempts were used to identify the 10RM loads. The participants were allowed 3-5 min rest between each attempt and between the three squat modalities [5,31]. ...
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The aim of this study was to assess the short-and long-term effects of resistance training (RT) with different stability requirements. Fifty-nine men underwent a 3-week familiarization period followed by a 7-week training period. During familiarization, all participants trained four sessions of squats with a Smith machine, free weights and free weights standing on a wobble board. After week-3, participants were randomized into a low (Smith machine), medium (Free-weight) or high (Wobble board) stability RT program, and Control group. All participants were tested pre-, after week-3 and post-intervention. Ten repetition maximum (10RM), rate of force development (RFD), electromyography (EMG) and maximum voluntary isometric contraction (MVIC) were tested in all three squat conditions in addition to countermovement jump (CMJ) on stable and unstable surfaces, and muscle thickness. After familiarization, greater 10RM loads (21.8-27.3%), MVIC (7.4-13.5%), RFD (29.7-43.8%) and CMJ (4.9-8.5%) were observed in all conditions. Between week 3 and 10, the Free-weight and Wobble board groups similarly improved 10RM in all conditions. Smith machine group demonstrated greater improvement in the trained exercise than the medium and high stability exercises. All training groups showed similar improvement in muscle thickness , RFD and MVIC. There was no CMJ improvement on the stable surface, but the Wobble board group demonstrated significantly greater improvement on the unstable surface. In conclusion, low, medium or high stability RT resulted in similar improvements in trained and non-trained testing conditions except for greater CMJ on the unstable surface in the Wobble group. Greater 10RM strength in trained than non-trained exercise was only observed in low stability group. Familiarization was associated with substantial improvements in 10RM and CMJ, with greater improvement associated with higher stability requirements. These findings suggest that high stability can increase strength, muscle thickness and explosive measurements similar to training with lower stability.
... Elastic Bands (EB) are increasing in popularity for strength training for both health and physical performance (Colado et al., 2010;2020;Colado and Triplett, 2008;Saeterbakken et al., 2014;Soria-Gila et al., 2015). EB have been shown to induce similar neuromuscular activation and adaptations to free weights and machines (Colado and Triplett, 2008;Colado et al., 2010;Sundstrup et al., 2012;Iversen et al., 2017), and provide optimal muscle stimulation across the entire range of motion for different resistance exercises such as the squat (Andersen et al., 2015;Joy et al., 2016). ...
... Nevertheless, most of the previous research has used EB with a lower tensile force or in combination with higher loads of constant resistance devices Andersen et al., 2015;Iversen et al., 2017). Only some studies are in line with our procedures and have used EB to achieve similar or even higher external resistance than the one used with constant resistance devices (Colado and Triplett, 2008;Colado et al., 2010;Andersen et al., 2016;Aboodarda et al., 2013). ...
... Regarding the load, obtained 5RM and 10RM (Table 1) are consistent with the percentages (Reynolds et al., 2006;Andersen et al., 2015) and kilograms (Joy et al., 2016) used by some studies with a varied subject population. On the other hand, some researches assessing free barbell squat reported lower average loads (Bryanton et al., 2012;Saeterbakken et al., 2016;Andersen et al., 2016;Iversen et al., 2017), and one study showed greater loads (Vigotsky et al., 2019). ...
... Based on this, the authors concluded that variable resistance can work as an effective adjunct to training, which might be related to the alterations in contractile machinery (i.e., neuromuscular structures) provoked by the concomitant utilization of EB and FW when raising or lowering loads. Nevertheless, longer studies (i.e., from 10 to 12 weeks) found no significant differences in strength gains between groups who trained with or without the simultaneous use of bungee cords (2,36). Therefore, it is possible that the additional effect of variable resistances on strength development occurs mainly at shorter time periods, being gradually reduced as the training progresses. ...
... Thus, it is possible to speculate that the combination between heavy loads and EB may reduce the enhancement in power output over shorter time periods; however, these effects seem to be mitigated at lighter loading conditions (i.e., power-oriented phase; bar velocities ranging between 1.0 and 1.2 m·s 21 ). These findings are in line with previous research showing similar improvements in power-related performance in both upper-limb (i.e., bench press) and lower-limb exercises (i.e., back squat and split squat) executed at moderate and heavy loading conditions (i.e., training intensities ranging from 70 to 92% 1RM, with EB providing a fixed resistance of ;20% 1RM [for bench press] and between 27 and 58% of the total resistance [for back and split squats]) in elite young athletes and other populations after comparing the chronic effects of variable and constant resistance training programs (2,43). This is the first study to demonstrate these effects under a mixed training scheme, which simultaneously combined nonballistic and ballistic exercises over a 4-week training period. ...
Article
Maximizing the neuromuscular capacities of players is a critical challenge during short soccer preseasons. This study compared the effects of two strength-power training regimes, on the strength, speed, and power performance of elite young soccer players during a 4-week preseason. Twenty-five under-20 players from the same club were pair-matched in two training groups as follows: traditional training group (TTG) (n=13), athletes performed half-squat (HS) and jump-squat (JS) exercises as traditionally prescribed; and EB group (EBG) (n=12), athletes performed HS and JS with EB attached to the barbell. Vertical jump height, 20-m sprint velocity, change-of-direction (COD) speed, HS and JS power, and one-repetition maximum (1RM) in the HS were assessed pre, post 2-week, and post 4-week of training. An ANOVA two-way with repeated measures was used to assess the effects of both training protocols over the experimental period. Both strategies were effective for significantly improving HS and JS power (effect sizes [ES] 1.00 - 1.77), HS 1RM (ES = 1.68 and 1.51 for TTG and EBG, respectively), vertical jumping ability (ES 0.37 - 0.65), and COD speed (ES = 0.81 and 0.39 for TTG and EBG, respectively), when comparing pre- and post-measures. In contrast, both TTG and EBG failed to increase 20-m sprint velocity (ES ranging between -0.54 and 0.23). In conclusion, both training schemes were able to improve the strength and power performance, but not the sprint capacity of young soccer players. To accelerate strength gains over very-short time periods (i.e., 2-week), variable resistance training may be advantageous. Conversely, to optimize power adaptations in ballistic exercises across a similar time period, traditional FW training may be preferred.
... Moreover, between-exercise variables may still be listed, as for example the type of load (e.g. cables, elastic bands, barbells/dumbbells, isoinertial devices) that appear to lead to different short-term or long-term strength and structural adaptations [11][12][13][14][15]. ...
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Manipulating resistance training variables is crucial to plan the induced stimuli correctly. When reporting the exercise variables in resistance training protocols, sports scientists and practitioners often refer to the load lifted and the total number of repetitions. The present conceptual review explores all within-exercise variables that may influence the strength and hypertrophic gains, and the changes in muscle architecture. Together with the (1) load and (2) the number of repetitions, (3) performing repetitions to failure or not to failure, (4) the displacement of the load or the range of movement (full or partial), (5) the portion of the partial movement to identify the muscle length at which the exercise is performed, (6) the total time under tension, the duration of each phase and the position of the two isometric phases, (7) whether the concentric, eccentric or concentric-eccentric phase is performed, (8) the use of internal or external focus and (9) the inter-set rest may all have repercussions on the adaptations induced by each resistance exercise. Manipulating one or more variable allows to increase, equalize or decrease the stimuli related to each exercise. Sports scientists and practitioners are invited to list all aforementioned variables for each exercise when reporting resistance training protocols.
... Sin embargo, la determinación de la carga de trabajo o test en bandas elásticas no se ha dilucidado en la literatura, como se tiene para los test de fuerza muscular dinámica en máquinas o pesas libres (7,8,11) . Pero, hoy es un método ampliamente utilizado por profesionales del acondicionamiento físico para la salud o rehabilitación física (12) . ...
Article
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RESUMEN La presente investigación tuvo por objetivo verificar la aplicación del parámetro antropométrico masa corporal en la evaluación de la fuerza dinámica mediante las bandas elásticas. Participaron 36 voluntarios hombres y mujeres sanos, con diferentes niveles de acondicionamiento físico, a los que se les aplicaron dos pruebas de fuerza, una con máquina de culturismo y otra con bandas elástica conectadas a una célula de carga, que posibilito la determinación de la fuerza generada durante la evaluación de la condición muscular de los grupos pectoral, dorsal ancho, cuádriceps, isquiotibiales; bíceps y tríceps. Los resultados identificaron diferencias significativas (p <0.01) para casi todos los grupos musculares analizados. Sin embargo, es posible concluir sobre la posibilidad de utilizar porcentajes de masa corporal en los protocolos existentes para el cálculo de cargas de prueba con banda elástica para diferentes grupos musculares para individuos sanos jóvenes y de mediana edad. ABSTRACT The objective of the present investigation was to verify the application of the anthropometric body mass parameter in the evaluation of dynamic force using elastic bands. 36 healthy male and female volunteers participated, with different levels of physical conditioning, who underwent two strength tests, one with a bodybuilding machine and the other with elastic bands connected to a load cell, which enabled the determination of strength generated during the evaluation of the muscular condition of the pectoral, latissimus dorsi, quadriceps, hamstring groups; biceps and triceps. The results identified significant differences (p <0.01) for almost all the muscle groups analyzed. However, it is possible to conclude the possibility of using body mass percentages from existing protocols to calculate elastic band test loads for different muscle groups for healthy young and middle-aged individuals.
... Regarding the VM, the electrodes were placed at 80% of the distance between the superior anterior iliac spine and the joint space at the anterior border of the medial collateral ligament [35]. Finally, for the RF the electrodes were placed in the middle of the anterior superior iliac spine line and the upper part of the patella [39]. All of the electrodes were covered with an elastic bandage to prevent their possible displacement during exercise. ...
Article
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The Monopodal Squat, Forward Lunge and Lateral Step-Up exercises are commonly performed with one's own body weight for rehabilitation purposes. However, muscle activity evaluated using surface electromyography has never been analyzed among these three exercises. Therefore, the objectives of the present study were to evaluate the amplitude of the EMG activity of the gluteus medius, gluteus maximus, biceps femoris, vastus lateralis, vastus medialis and rectus femoris muscles in participants performing the Lateral Step-Up, Forward Lunge and Monopodal Squat exercises. A total of 20 physically active participants (10 men and 10 women) performed 5 repetitions at 60% (5 repetition maximum) in each of the evaluated exercises. The EMG amplitude was calculated in percentage of the maximum voluntary contraction. The Monopodal Squat exercise showed a higher EMG activity (p ≤ 0.001) in relation to the Lateral Step-Up and Forward Lunge exercises in all of the evaluated muscles (d > 0.6) except for the rectus femoris. The three exercises showed significantly higher EMG activity in all of the muscles that were evaluated in the concentric phase in relation to the eccentric one. In the three evaluated exercises, vastus lateralis and vastus medialis showed the highest EMG activity, followed by gluteus medius and gluteus maximus. The Monopodal Squat, Forward Lunge and Lateral Step-Up exercises not only are recommended for their rehabilitation purposes but also should be recommended for performance objectives and strength improvement in the lower limbs.
... However, when training with constant resistance, maximal effort (force) is required at the beginning of the concentric lifting phase, decreasing neuromuscular stress throughout the concentric phase [5] . In this sense, several studies have analysed and compared kinematics, kinetics and muscle activation between constant and variable resistances [5][6][7][8][9][10][11] . Other studies have evaluated the effectiveness of accommodation and constant resistance training [12][13][14][15][16][17] . ...
Article
In strength or resistance training, the patterns of movement of the load and the muscle activation can be adapted to the training objective according to the muscle conditioning machine selected. Traditionally, free-weight bench press is extensively used for athlete training. One of the main features of such kind of machine is the significant influence of the inertial forces in the muscle forces that the athlete has to develop. In this paper, a bench press which is able to maintain an almost constant force resistance is proposed. Then, the proposed constant-force bench press is compared to the traditional free-weight resistance bench press. Experimental data measured in a test session with free-weight resistance are used as an input for a mathematical model of the bench press that allows estimating three meaningful variables of the exercise performance: the shoulder vertical force, the net joint moment at the shoulder and the muscular power. These results are compared with those obtained by assuming a constant-force resistance, finding significant differences between both resistance systems. Constant-force resistance results in a less fluctuating force curve, lower peaks of the joint moment and muscular power, and small variance between different exercise repetitions.
... e participants' dominant hand was used to holda semisupinated grip [26], and the elbow was held closed to the body. Each participant had three attempts with a contraction duration of five seconds and a 60-second rest between each attempt [27]. Participants were carefully instructed to contract "as fast and forcefully as possible." ...
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The aim of this study was to determine the effects of a 10-week strength training intervention on isometric strength, rate of force development (RFD), physical function (stair climbing, rising from a chair, and preferred and maximal walking speed), and physical activity among frail elderly people receiving home-care services. Thirty participants were randomly assigned (by sex) to a control group (CON) or a strength training group (ST) performing a supervised training programme using elastic bands, box-lifting, and body weight exercises twice per week. Twenty-three participants were selected to complete the study (age 84.9 ± 6.1 years). For the ST, only improvement in muscle properties was the peak RFD in leg extension (). No significant differences were observed in muscle properties for the control group (CON) () or between groups (). There were no changes within and between the groups in physical function () or physical activity levels (). The results of this pilot study did not demonstrate greater improvements in muscle properties and physical function and improved physical activity after attending a home-based resistance program compared to physical activity advise; however, larger population studies should examine these findings. This trial is registered with ISRCTN10967873.
... Commonly used compound resisted hip extension exercises are the squat, deadlift, and hip thrust. Furthermore, to optimize the activation of specific muscles or for the purpose of variation in a periodized resistance training program, it is common to perform different variations of the same exercise (1)(2)(3). This can be done, for example, by moving the placement of the load horizontally (e.g., front squat vs back squat) relative to the axis of rotation (e.g., the hip joint). ...
Article
The aim of the study was to compare the muscle activation level of the gluteus maximus, biceps femoris and erector spinae in the hip thrust, barbell deadlift and hex bar deadlift; each of which are compound resisted hip-extension exercises. After two familiarization sessions, 13 resistance-trained men performed a 1-RM in all three exercises in one session, in randomized and counterbalanced order. The whole ascending movement (concentric phase), as well as its lower and upper part (whole movement divided in two), were analyzed. The hip thrust induced greater activation of the gluteus maximus compared to the hex bar deadlift in the whole (16%, p=0.025) and the upper part (26%, p=0.015) of the movement. For the whole movement, the biceps femoris was more activated during barbell deadlift compared to both the hex bar deadlift (28%, p<0.001) and hip thrust (20%, p=0.005). In the lower part of the movement, biceps femoris activation was respectively 48% and 26% higher for the barbell deadlift (p<0.001) and hex bar deadlift (p=0.049) compared to hip thrust. Biceps femoris activation in the upper part of the movement was 39% higher for the barbell deadlift compared to the hex bar deadlift (p=0.001) and 34% higher for the hip thrust compared to the hex bar deadlift (p=0.002). No differences were displayed for erector spinae activation (p=0.312-0.859). In conclusion, the barbell deadlift was clearly superior in activating the biceps femoris compared to the hex bar deadlift and hip thrust, whereas the hip thrust provided the highest gluteus maximus activation.
Article
Background and Study Aim. The aim of this study was to examine the effects of different training programs on the improvement of motoric and swimming performance prepubescent swimmers. Material and Methods. Forty-five children between the ages of 9 -11 years with at least 2 years of training experiences, participated in the study. Three different [(1) dry-land with elastic resistance band group + swimming (ERB); (2) dry-land without elastic resistance band (DL) + swimming and (3) swimming group (SG) with swimming training alone] training group were formed. And a 12-week training program was implemented thought the study. Biceps, chest, waist, hip, thigh body circumference measurements were taken from all participants. Vertical jump (VJ), flexed-arm strength (FAS), speed, upper body strength (UBS), Standing horizontal jump (SHJ), flexibility, aerobic endurance (AE), balance, and 50 m freestyle swimming (FS) score were tested on the participants. As statistical analysis, normality and homogeneity of variance assumption were checked (Shapiro-Wilk and Levene tests, respectively). A non-normal distribution was found. The values of each variable were expressed as mean ± standard deviation, and median. The training effects within the groups were evaluated using analyses of Friedman for repeated measures and the level of significance was set at p<0.05 for all tests. Results. There was a significant difference in SHJ, UBS, FAS, speed, and FS score among the assessment times 1-3 and 1-4 in both of ERB and DL training groups (p<0.05). ERB and DL training were significantly effective compared to the SG on VJ, FAS, speed, UBS, and freestyle swimming performance (p<0.05). Conclusions: The study findings showed that DL training more effected relatively on motoric performance.
Article
The aim of the study was to compare the electromyographic activity of vastus lateralis, vastus medialis, rectus femoris and biceps femoris when performing the squat with constant resistance or variable resistance with two or four elastic bands, respectively contributing with a mean of 39% and 73% of the total loads. Nineteen resistance-trained women performed 6 repetition maximum (6-RM) using three different experimental conditions: free weights (FW), free weights + 2 elastic bands (FW+2EB) and free weights + 4 elastic bands (FW+4EB). During analyses, each repetition was divided into six phases; upper (more extended knee), middle and lower phase of the descending and ascending movement. Increased activation in the upper parts of the movement was observed for both variable resistance conditions compared to constant resistance (9-51%, p<0.001-0.050). Further, a dose-response effect of variable resistance was observed in the upper ascending movement, with 4 elastic bands increasing muscle activation more than 2 elastic bands (7 - 28%, p = 0.003-0.007). For the whole movement, a 12% higher activation of the biceps femoris was observed for FW+4EB compared to FW (p = 0.005). There were no differences between the other conditions in any of the muscles (p = 0.077 - 1.000). In conclusion, performing the squat using free weights in combination with elastic bands appears to be preferable compared to free weights alone, and more so with a high contribution from variable resistance to the total load.
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The purpose of this study was to assess the effect of heavy/slow movements and variable resistance training on peak power and strength development. Forty-eight National Collegiate Athletic Association (NCAA) Division I athletes (age: 21.4 +/- 2.1 years, all men) were recruited for this 12-week training intervention study. Maximum strength and jumping power were assessed before and after the training program. Athletes were randomly assigned to 1 of 3 training groups: heavy resistance/slow movement (Slow), lighter resistance and fast movement (Fast), or fast movements with accommodated resistance (FACC). All training groups performed similar training programs comprising free weight resistance training with lower-body compound exercises. The only difference among the training interventions was the speed at which subjects performed the squat exercise and the use of bands (Slow group: 0.2-0.4 meters/second; Fast group: 0.6-0.8 meters/second; FACC group trained 0.6-0.8 meters/second with the addition of accommodated resistance in the form of large elastic bands). Post-test data revealed a significant difference between power improvements between the Slow and FACC groups (p = 0.02). Percent increases and effect sizes (ES) demonstrated a much greater treatment effect in the FACC group (17.8%, ES = 1.06) with the Fast group (11.0%, ES = 0.80) adapting more than the Slow group (4.8%, ES = 0.28). The FACC and Slow groups improved strength comparatively (FACC: 9.44%, ES = 1.10; Slow: 9.59%, ES = 1.08). The Fast group improved strength considerably less, 3.20% with an effect size of only 0.38. Variable resistance training with elastic bands appears to provide greater performance benefits with regard to peak force and peak power than heavy, slow resistance exercise. Sports conditioning professionals can utilize bands, and high-speed contractions, to increase power development.
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Core stability and core strength have been subject to research since the early 1980s. Research has highlighted benefits of training these processes for people with back pain and for carrying out everyday activities. However, less research has been performed on the benefits of core training for elite athletes and how this training should be carried out to optimize sporting performance. Many elite athletes undertake core stability and core strength training as part of their training programme, despite contradictory findings and conclusions as to their efficacy. This is mainly due to the lack of a gold standard method for measuring core stability and strength when performing everyday tasks and sporting movements. A further confounding factor is that because of the differing demands on the core musculature during everyday activities (low load, slow movements) and sporting activities (high load, resisted, dynamic movements), research performed in the rehabilitation sector cannot be applied to the sporting environment and, subsequently, data regarding core training programmes and their effectiveness on sporting performance are lacking. There are many articles in the literature that promote core training programmes and exercises for performance enhancement without providing a strong scientific rationale of their effectiveness, especially in the sporting sector. In the rehabilitation sector, improvements in lower back injuries have been reported by improving core stability. Few studies have observed any performance enhancement in sporting activities despite observing improvements in core stability and core strength following a core training programme. A clearer understanding of the roles that specific muscles have during core stability and core strength exercises would enable more functional training programmes to be implemented, which may result in a more effective transfer of these skills to actual sporting activities.
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This study examined mean integrated electromyography (I-EMG) for the quadriceps and hamstring muscle groups, as well as mean and peak vertical ground reaction forces (GRFs), for 3 conditions of the back squat. Conditions included (a) squat with barbell and weight plates, (b) squat with barbell and weight plates plus chains hung on each end of the barbell to replace approximately 10% of the squat load, and (c) squat with barbell and weight plates plus elastic bands offering resistance equivalent to approximately 10% of the squat load. Weight plates equal to the load added by either the chains or elastic bands were removed for the latter 2 squat conditions. Vertical GRFs were obtained during a single testing session for all 3 squat conditions. The tests were performed on a 2-cm thick aluminum platform (0.76 x 1.0 m) bolted directly to a force plate (OR6-5-2000, AMTI, Watertown, MA). Surface electrode I-EMG data from the quadriceps and hamstrings were recorded at 500 Hz. The exercise order was randomly determined for 11 NCAA Division I athletes who had experience using these types of squats. A repeated measures analysis of covariance revealed no differences in I-EMG and GRF during the eccentric or concentric phase for any of the 3 squat conditions. Analyses showed that mean GRF and I-EMG was significantly different between eccentric and concentric phases for all groups. The results question the usefulness of performing squats combining barbell and weight plates with chain and elastic resistance.
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The purpose of this cross-sectional study was to evaluate the effect of unstable and unilateral resistance exercises on trunk muscle activation. Eleven subjects (6 men and 5 women) between 20 and 45 years of age participated. Six trunk exercises, as well as unilateral and bilateral shoulder and chest presses against resistance, were performed on stable (bench) and unstable (Swiss ball) bases. Electromyographic activity of the upper lumbar, lumbosacral erector spinae, and lower-abdominal muscles were monitored. Instability generated greater activation of the lower-abdominal stabilizer musculature (27.9%) with the trunk exercises and all trunk stabilizers (37.7-54.3%) with the chest press. There was no effect of instability on the shoulder press. Unilateral shoulder press produced greater activation of the back stabilizers, and unilateral chest press resulted in higher activation of all trunk stabilizers, when compared with bilateral presses. Regardless of stability, the superman exercise was the most effective trunk-stabilizer exercise for back-stabilizer activation, whereas the side bridge was the optimal exercise for lower-abdominal muscle activation. Thus, the most effective means for trunk strengthening should involve back or abdominal exercises with unstable bases. Furthermore, trunk strengthening can also occur when performing resistance exercises for the limbs, if the exercises are performed unilaterally.
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The objective of this study was to determine differences in electromyographic (EMG) activity of the soleus (SOL), vastus lateralis (VL), biceps femoris (BF), abdominal stabilizers (AS), upper lumbar erector spinae (ULES), and lumbo-sacral erector spinae (LSES) muscles while performing squats of varied stability and resistance. Stability was altered by doing the squat movement on a Smith machine, a free squat, and while standing on two balance discs. Fourteen male subjects performed the movements. Activities of the SOL, AS, ULES, and LSES were highest during the unstable squat and lowest with the Smith machine protocol (p < 0.05). Increased EMG activity of these muscles may be attributed to their postural and stabilization role. Furthermore, EMG activity was higher during concentric contractions compared to eccentric contractions. Performing squats on unstable surfaces may permit a training adaptation of the trunk muscles responsible for supporting the spinal column (i.e., erector spinae) as well as the muscles most responsible for maintaining posture (i.e., SOL).
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The swiss is widely used in the recreational training environment as a supplement to conventional resistance training. One such application is to use the swiss ball as a bench support for bench press exercise. There is no evidence to indicate that the use of a swiss ball is beneficial for resistance training exercise. This study investigated muscle activity using surface electromyography of upper-body and abdominal muscles during the concentric and eccentric phases of the bench press on and off a swiss ball. Volunteers for this study were 14 resistance-trained subjects who performed isolated concentric and eccentric bench press repetitions using the 2 test surfaces with a 2-second cadence at a load equivalent to 60% maximum force output. The average root mean square of the muscle activity was calculated for each movement, and perceived exertion during the tasks was collected using a Borg Scale. The results of the study showed that deltoid and abdominal muscle activity was increased for repetitions performed using the swiss ball. Increased deltoid muscle activity supports previous findings for increased activity when greater instability is introduced to the bench press movement. Abdominal muscle activity increases were not hypothesized, but this finding provides scientific evidence for anecdotal reasoning behind swiss ball use as a potential core stability training device.
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The purpose of this study was to examine the extent of activation in various trunk muscles during dynamic weight-training and isometric instability exercises. Sixteen subjects performed squats and deadlifts with 80% 1 repetition maximum (1RM), as well as with body weight as resistance and 2 unstable calisthenic-type exercises (superman and sidebridge). Electromyographic (EMG) activity was measured from the lower abdominals (LA), external obliques (EO), upper lumbar erector spinae (ULES), and lumbar-sacral erector spinae (LSES) muscle groups. Results indicated that the LSES EMG activity during the 80% 1RM squat significantly exceeded 80% 1RM deadlift LSES EMG activity by 34.5%. The LSES EMG activity of the 80% 1RM squat also exceeded the body weight squat, deadlift, superman, and sidebridge by 56, 56.6, 65.5, and 53.1%, respectively. The 80% 1RM deadlift ULES EMG activity significantly exceeded the 80% 1RM squat exercise by 12.9%. In addition, the 80% 1RM deadlift ULES EMG activity also exceeded the body weight squat, deadlift, superman, and sidebridge exercises by 66.7, 65.5, 69.3, and 68.6%, respectively. There were no significant changes in EO or LA activity. Therefore, the augmented activity of the LSES and ULES during 80% 1RM squat and deadlift resistance exercises exceeded the activation levels achieved with the same exercises performed with body weight and selected instability exercises. Individuals performing upright, resisted, dynamic exercises can achieve high trunk muscle activation and thus may not need to add instability device exercises to augment core stability training.
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This brief review examines some of the methods used to infer central control strategies from surface electromyogram (EMG) recordings. Among the many uses of the surface EMG in studying the neural control of movement, the review critically evaluates only some of the applications. The focus is on the relations between global features of the surface EMG and the underlying physiological processes. Because direct measurements of motor unit activation are not available and many factors can influence the signal, these relations are frequently misinterpreted. These errors are compounded by the counterintuitive effects that some system parameters can have on the EMG signal. The phenomenon of crosstalk is used as an example of these problems. The review describes the limitations of techniques used to infer the level of muscle activation, the type of motor unit recruited, the upper limit of motor unit recruitment, the average discharge rate, and the degree of synchronization between motor units. Although the global surface EMG is a useful measure of muscle activation and assessment, there are limits to the information that can be extracted from this signal.
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The objective of this study was to assess the electromyographic (EMG) activity of rectus abdominis (upper and lower part) and external oblique during sit-ups performed on BOSU ball(s). 24 men participated in a familiarization session and in the next session performed the experimental tests in randomized order. The sit-ups were performed with 10 repetitions with body-weight and with 10 repetitions maximum (10-RM) using elastic bands as external resistance in four different conditions: 1) on a stable surface, 2) with BOSU ball under feet (dome side down, lower-body instability), 3) BOSU ball under back/gluteus (dome side up, upper-body instability) and 4) with BOSU balls under both feet and back/gluteus (dual instability). The feet were not attached to the surface. We observed that with body-weight, external oblique activation was decreased by upper-body instability and dual instability by 22-24% (P=0.002-0.006), whereas rectus abdominis was not affected by surface. Using 10-RM loads, the upper and lower rectus abdominis activities were increased by upper body and dual instability by 21-24% compared to stable surface (P=<0.001-0.036). Further, lower-body instability did not affect muscle activities significantly with either load for any condition. Hence, BOSU balls under back/gluteus can both increase and decrease abdominal muscle activation depending on the load, whereas placing a BOSU ball under feet with the dome side down had little impact.
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Core stability training, operationally defined as training focused to improve trunk and hip control, is an integral part of athletic development, yet little is known about its direct relation to athletic performance. This systematic review focuses on identification of the association between core stability and sports-related performance measures. A secondary objective was to identify difficulties encountered when trying to train core stability with the goal of improving athletic performance. A systematic search was employed to capture all articles related to athletic performance and core stability training that were identified using the electronic databases MEDLINE, CINAHL and SPORTDiscus™ (1982-June 2011). A systematic approach was used to evaluate 179 articles identified for initial review. Studies that performed an intervention targeted toward the core and measured an outcome related to athletic or sport performances were included, while studies with a participant population aged 65 years or older were excluded. Twenty-four in total met the inclusionary criteria for review. Studies were evaluated using the Physical Therapy Evidence Database (PEDro) scale. The 24 articles were separated into three groups, general performance (n = 8), lower extremity (n = 10) and upper extremity (n = 6), for ease of discussion. In the majority of studies, core stability training was utilized in conjunction with more comprehensive exercise programmes. As such, many studies saw improvements in skills of general strengths such as maximum squat load and vertical leap. Surprisingly, not all studies reported measurable increases in specific core strength and stability measures following training. Additionally, investigations that targeted the core as the primary goal for improved outcome of training had mixed results. Core stability is rarely the sole component of an athletic development programme, making it difficult to directly isolate its affect on athletic performance. The population biases of some studies of athletic performance also confound the results. Targeted core stability training provides marginal benefits to athletic performance. Conflicting findings and the lack of a standardization for measurement of outcomes and training focused to improve core strength and stability pose difficulties. Because of this, further research targeted to determine this relationship is necessary to better understand how core strength and stability affect athletic performance.
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The purpose of the study was to compare force output and muscle activity of leg and trunk muscles in isometric squats executed on stable surface (i.e. floor), power board, BOSU ball and balance cone. Fifteen healthy males (23.3 ± 2.7 years, mass: 80.5 ± 8.5 kg, height: 1.81 ± 0.09 m) volunteered. The force output and electromyographic (EMG) activities of the rectus femoris, vastus medialis, vastus lateralis, biceps femoris, soleus, rectus abdominis, oblique external and erector spinae were assessed. The order of the surfaces was randomized. One familiarization session was executed prior to the experimental test. Compared to stable surface (749 ± 222 N), the force output using power board was similar (-7%, P = 0.320), but lower for BOSU ball (-19%, P = 0.003) and balance cone (-24%, P ≤ 0.001). The force output using BOSU ball and balance cone was ∼13% (P = 0.037) and ∼18% (P = 0.001) less than the power board. There were similar EMG activities between the surfaces in all muscles except for rectus femoris, in which stable squat provided greater EMG activity than the other exercises (P = 0.004 - 0.030). Lower EMG activity was observed in rectus femoris using balance cone compared to BOSU ball (P = 0.030). In conclusion, increasing the instability of the surface during maximum effort isometric squats usually maintains the muscle activity of lower limb and superficial trunk muscles although the force output is reduced. This suggests that unstable surfaces in the squat may be beneficial in rehabilitation and as a part of periodized training programs, as similar muscle activity can be achieved with reduced loads.
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We examined the effects of jump training with negative (-30% of the subject's body weight (BW)) VS. positive loading (+30% BW) on the mechanical behaviour of leg extensor muscles. 32 men were divided into control (CG), negative loading (NLG), or positive loading training group (PLG). Both training groups performed maximal effort countermovement jumps (CMJ) over a 7-week training period. The impact of training on the mechanical behaviour of leg extensor muscles was assessed through CMJ performed with external loads ranging from -30% BW to +30% BW. Both training groups showed significant ( P≤0.013) increase in BW CMJ height (NLG: 9%, effect size (ES)=0.85, VS. PLG: 3.4%, ES=0.31), peak jumping velocity ( V(peak); NLG: 4.1%; ES=0.80, P=0.011, VS. PLG: 1.4%, ES=0.24; P=0.017), and depth of the countermovement (Δ H(ecc); NLG: 20%; ES=-1.64, P=0.004, VS. PLG: 11.4%; ES=-0.86, P=0.015). Although the increase in both the V(peak) and Δ H(ecc) were expected to reduce the recorded ground reaction force, the indices of force- and power-production characteristics of CMJ remained unchanged. Finally, NLG (but not PLG) suggested load-specific improvement in the movement kinematic and kinetic patterns. Overall, the observed results revealed a rather novel finding regarding the effectiveness of negative loading in enhancing CMJ performance which could be of potential importance for further development of routine training protocols. Although the involved biomechanical and neuromuscular mechanisms need further exploration, the improved performance could be partly based on an altered jumping pattern that utilizes an enhanced ability of leg extensors to provide kinetic and power output during the concentric jump phase.
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The use of elastic bands in resistance training has been reported to be effective in increasing performance-related parameters such as power, rate of force development (RFD), and velocity. The purpose of this study was to assess the following measures during the free-weight back squat exercise with and without elastic bands: peak and mean velocity in the eccentric and concentric phases (PV-E, PV-C, MV-E, MV-C), peak force (PF), peak power in the concentric phase, and RFD immediately before and after the zero-velocity point and in the concentric phase (RFDC). Twenty trained male volunteers (age = 26.0 ± 4.4 years) performed 3 sets of 3 repetitions of squats (at 55% one repetition maximum [1RM]) on 2 separate days: 1 day without bands and the other with bands in a randomized order. The added band force equaled 20% of the subjects' 55% 1RM. Two independent force platforms collected ground reaction force data, and a 9-camera motion capture system was used for displacement measurements. The results showed that PV-E and RFDC were significantly (p < 0.05) greater with the use of bands, whereas PV-C and MV-C were greater without bands. There were no differences in any other variables. These results indicate that there may be benefits to performing squats with elastic bands in terms of RFD. Practitioners concerned with improving RFD may want to consider incorporating this easily implemented training variation.
Article
The purpose of this paper is to address four aspects of surface electromyography associated with crosstalk between adjacent recording sites. The first issue that is addressed in the potential crosstalk between electrodes located on muscles with different functions: antagonist pairs, or muscles with one common and one different function (i.e. soleus/peroneus longus or soleus/ gastrocnemius). Practical functional tests are utilized to demonstrate the crosstalk between muscle pairs to be negligible. The second goal is to estimate the depth of pick-up and the crosstalk between myoelectric signals from agonist muscles using a theoretical model. The depth of pick-up was estimated to be 1.8 cm (including a 2 mm layer of skin and fat) using electrodes of 49 mm(2) with bipolar spacing of 2.0 cm. A cross-correlation technique is demonstrated which predicts the common signal (crosstalk) between surface electrodes with electrode-pair spacing of 1 cm around a hypothetical muscle. The predicted crosstalk using cross-correlation measures was 49% at 1 cm electrode-pair spacing dropping to 13% at 2 cm spacing and 4% at 3 cm. The third part compares these predictions with crosstalk measures from experimental recordings taken from electrode pairs spaced 2.5 cm apart around the quadriceps. At 2.5 cm spacing there was 22-24% common signal dropping to between 4-7% at 5 cm and to between 1 and 2% at 7.5 cm. The fourth and last component of this report assesses three methods to decrease the range of pick-up and thereby potential crosstalk: electrodes of smaller surface area, reduced bipolar spacing and mathematical differentiation. All three techniques reduce the common signal by varying amounts; all three techniques combined reduce the predicted crosstalk for the 1.0 cm electrode-pair spacing from 49-10.5%.
Article
The present study investigated the effects of training combining elastic tension, free weights, and the bench press. Eleven college-aged men (untrained) in the bench press participated in the 13-week study. The participants were first given instructions and then practiced the bench press, followed by a one-repetition maximum (1RM) test of baseline strength. Subjects were then trained in the bench press for 3 weeks to allow for the beginning of neural adaptation. After another 1RM test, participants were assigned to 1 of 2 conditions for the next 3 weeks of training: 85% Free-Weight Tension, 15% Elastic Tension (BAND), or 100% Free-Weight Tension (STAND). After 3 weeks of training and a third 1RM max test, participants switched treatments, under which they completed the final 3 weeks of training and the fourth 1RM test. Analysis via analysis of covariance revealed a significant (p ≤ 0.05) main effect for time and interaction effect for Treatment (BAND vs. STAND). Subsequent analysis via paired-samples t-test revealed the BAND condition was significantly better (p = 0.05) at producing raw gains in 1RM strength. (BAND 9.95 ± 3.7 kg vs. STAND 7.56 ± 2.8 kg). These results suggest that the addition of elastic tension to the bench press may be an effective method of increasing strength.
Article
Newton's second law of motion describes the acceleration of an object as being directly proportional to the magnitude of the net force, in the same direction as the net force and inversely proportional to its mass (a = F/m). With respect to linear motion, mass is also a numerical representation of an object's inertia, or its resistance to change in its state of motion and directly proportional to the magnitude of an object's momentum at any given velocity. To change an object's momentum, thereby increasing or decreasing its velocity, a proportional impulse must be generated. All motion is governed by these relationships, independent of the exercise being performed or the movement type being used; however, the degree to which this governance affects the associated kinematics, kinetics and muscle activity is dependent on the resistance type. Researchers have suggested that to facilitate the greatest improvements to athletic performance, the resistance-training programme employed by an athlete must be adapted to meet the specific demands of their sport. Therefore, it is conceivable that one mechanical stimulus, or resistance type, may not be appropriate for all applications. Although an excellent means of increasing maximal strength and the rate of force development, free-weight or mass-based training may not be the most conducive means to elicit velocity-specific adaptations. Attempts have been made to combat the inherent flaws of free weights, via accommodating and variable resistance-training devices; however, such approaches are not without problems that are specific to their mechanics. More recently, pneumatic-resistance devices (variable) have been introduced as a mechanical stimulus whereby the body mass of the athlete represents the only inertia that must be overcome to initiate movement, thus potentially affording the opportunity to develop velocity-specific power. However, there is no empirical evidence to support such a contention. Future research should place further emphasis on understanding the mechanical advantages/disadvantages inherent to the resistance types being used during training, so as to elicit the greatest improvements in athletic performance.
Article
This study examined the possibility of using movement velocity as an indicator of relative load in the bench press (BP) exercise. One hundred and twenty strength-trained males performed a test (T1) with increasing loads for the individual determination of the one-repetition maximum (1RM) and full load-velocity profile. Fifty-six subjects performed the test on a second occasion (T2) following 6 weeks of training. A very close relationship between mean propulsive velocity (MPV) and load (%1RM) was observed (R (2)=0.98). Mean velocity attained with 1RM was 0.16+/-0.04 m x s(-1) and was found to influence the MPV attained with each %1RM. Despite a mean increase of 9.3% in 1RM from T1 to T2, MPV for each %1RM remained stable. Stability in the load-velocity relationship was also confirmed regardless of individual relative strength. These results confirm an inextricable relationship between relative load and MPV in the BP that makes it possible to: 1) evaluate maximal strength without the need to perform a 1RM test, or test of maximum number of repetitions to failure (XRM); 2) determine the %1RM that is being used as soon as the first repetition with any given load is performed; 3) prescribe and monitor training load according to velocity, instead of percentages of 1RM or XRM.
Article
Elastic bands added to traditional free-weight techniques have become a part of suggested training routines in recent years. Because of the variable loading patterns of elastic bands (i.e., greater stretch produces greater resistance), it is necessary to quantify the exact loading patterns of bands to identify the volume and intensity of training. The purpose of this study was to determine the length vs. tension properties of multiple sizes of a set of commonly used elastic bands to quantify the resistance that would be applied to free-weight plus elastic bench presses (BP) and squats (SQ). Five elastic bands of varying thickness were affixed to an overhead support beam. Dumbbells of varying weights were progressively added to the free end while the linear deformation was recorded with each subsequent weight increment. The resistance was plotted as a factor of linear deformation, and best-fit nonlinear logarithmic regression equations were then matched to the data. For both the BP and SQ loading conditions and all band thicknesses tested, R values were greater than 0.9623. These data suggest that differences in load exist as a result of the thickness of the elastic band, attachment technique, and type of exercise being performed. Facilities should adopt their own form of loading quantification to match their unique set of circumstances when acquiring, researching, and implementing elastic band and free-weight exercises into the training programs.
Article
The purpose of this study was to explore the effects of a 7-week heavy elastic band and weighted-chain program on maximum muscular strength and maximum power in the bench press exercise. Thirty-six (n = 36) healthy men aged 18-30 years old, from the Robert Morris University football team, volunteered to participate in this study. During the first week, predicted 1 repetition maximum (1RM) bench press and a 5RM speed bench press tests were conducted. Subjects were randomly divided into 3 groups (n = 12): elastic band (EB), weighted chain (WC), and traditional bench (C). During weeks 2-8 of the study, subjects were required to follow the prescribed resistance training program. Mean and SD of the predicted 1RM bench press and 5RM speed bench press were computed. A two-factor (method X time) analysis was applied to identify significant differences between the training groups. Significance was set at alpha = 0.05. Results indicated a significant time (p < 0.05) but no group effect for both predicted 1RM (kg) and 5RM peak power tests (watts). Although not significant, results did show greater nonsignificant improvements in the EB (848-883 W) and WC groups (856-878 W) vs. control (918-928 W) when the 2 highest and greatest values were selected regarding peak power. The use of EB and WC in conjunction with a general off-season strength and conditioning program can increase overall maximum upper-body strength in a sample of Division 1-AA football players. These types of training modalities add a unique training style and more flexibility with respect to exercise prescription for athletes and strength practitioners.
Article
The purpose of this study was to investigate the effects of chain- (CBP) and plate-loaded (PBP) bench press training on measures of strength, shoulder pain, and muscle soreness in Division II baseball players. Twenty-eight subjects with previous resistance training experience (4.8 +/- 2.7 years) completed the study while participating in off-season baseball practice. All subjects completed a one-repetition maximum pre- and posttest on the CBP and PBP and reported shoulder pain and muscle soreness on 15 occasions during training. Two treatment groups, CBP and PBP, trained 2 d.wk for 9 weeks during the off-season with a linear periodization strength training program. The CBP group used chains attached to the bar as the entire load, and the PBP group used only traditional plate-loaded resistance. The chains provided a variable resistance, with a reduction in load during the descent as the weight collected on the floor and with the load increasing during ascent as the weight was lifted from the floor. Statistically significant increases were found in strength scores after training for the CBP test (p < 0.001) and the PBP test (p < 0.001). Both groups were able to improve strength on the CBP and PBP, but no significant differences were found in strength gains between the groups on the CBP and PBP tests. Although levels of pain and soreness were not significantly different, a threefold difference was found for perceived levels of shoulder pain (mean totals of 2.15 vs. 6.14), whereas reported soreness was similar (9.38 vs. 10.57) for the CBP and PBP group, respectively. The data indicate that training with chain- and plate-loaded resistance produce similar short-term strength improvement on the chain- and plate-loaded bench press. Baseball players may benefit from CBP training with improved free-weight strength while minimizing shoulder stress.
Changes in strength, body composition and anthropometric measures for groups training with constant resistance and variable resistance training procedures was compared. Thirty-six male volunteers were randomly assigned to one of three groups: Constant Resistance (CR), Variable Resistance (VR) and Control (C). Strength training was conducted 3 days per week, 45 min per day, for 10 weeks. The results demonstrated that both the CR and the VR groups increased muscular strength. The CR group demonstrated significant increases in strength over the VR group when strength was assessed by CR procedures. Conversely, the VR group demonstrated significant increases in strength over the CR group when strength was assessed by VR procedures. Neither group exhibited superiority over the other relative to changes in body composition and anthropometric measures. The significance of these results is discussed.
Article
To compare the effect of constant resistance (CR) and variable resistance (VR) training on full range-of-motion (ROM) strength development, 22 men and 27 women (age = 26 +/- 5 yr) were randomly assigned to either a CR training group (N = 17), a VR training group (N = 17), or a control group (N = 15) that did not train. The CR and VR groups trained 2 to 3 d.wk-1 for 10 wk. Subjects completed one set of full ROM (120 to 0 degrees of flexion) bilateral knee extensions with an amount of weight that allowed 8 to 12 repetitions during each training session. For the VR group, resistance was varied with a cam supplied by the manufacturer (Nautilus). For the CR group, the cam was removed and replaced with a round sprocket. Prior to and after training, maximal voluntary isometric torque was measured at 9, 20, 35, 50, 65, 80, 95, and 110 degrees of knee flexion. Analysis of covariance indicated that the VR and CR groups gained strength at all angles (P less than or equal to 0.05) when compared to the control. [table: see text] There was no difference (P greater than 0.05) between the CR and VR groups at any angle, and the magnitude of strength gained was similar (P greater than 0.05) among angles for both groups. These data indicate that both CR and VR knee extension training elicit full ROM strength development.
From the mechanical point of view the spinal system is highly complex, containing a multitude of components, passive and active. In fact, even if the active components (the muscles) were exchanged by passive springs, the total number of elements considerably exceeds the minimum needed to maintain static equilibrium. In other words, the system is statically highly indeterminate. The particular role of the active components at static equilibrium is to enable a virtually arbitrary choice of posture, independent of the distribution and magnitude of the outer load albeit within physiological limits. Simultaneously this implies that ordinary procedures known from the analysis of mechanical systems with passive components cannot be applied. Hence the distribution of the forces over the different elements is not uniquely determined. Consequently nervous control of the force distribution over the muscles is needed, but little is known about how this achieved. This lack of knowledge implies great difficulties at numerical simulation of equilibrium states of the spinal system. These difficulties remain even if considerable reductions are made, such as the assumption that the thoracic cage behaves like a rigid body. A particularly useful point of view about the main principles of the force distributions appears to be the distinction between a local and a global system of muscles engaged in the equilibrium of the lumbar spine. The local system consists of muscles with insertion or origin (or both) at lumbar vertebrae, whereas the global system consists of muscles with origin on the pelvis and insertions on the thoracic cage. Given the posture of the lumbar spine, the force distribution over the local system appears to be essentially independent of the outer load of the body (though the force magnitudes are, of course, dependent on the magnitude of this load). Instead different distributions of the outer load on the body are met by different distributions of the forces in the global system. Thus, roughly speaking, the global system appears to take care of different distributions of outer forces on the body, whereas the local system performs an action, which is essentially locally determined (i.e. by the posture of the lumbar spine). The present work focuses on the upright standing posture with different degree of lumbar lordosis. The outer load is assumed to consist of weights carried on the shoulders. By reduction of the number of unknown forces, which is done by using a few different principles, a unique determination of the total force distributions at static equilibrium is obtained.(ABSTRACT TRUNCATED AT 400 WORDS)
Activation patterns of the four thigh muscles (rectus femoris, vastus medialis, vastus lateralis and semimembranosus) were investigated in static leg extension through the entire range of extension movement in three testing postures: sitting, recumbent and supine. Special interest was focused on the role of the two-joint muscles. Five male students performed both maximal and submaximal efforts. The highest force values were observed when the knee was almost extended (150 degrees), while the agonists were the most active in flexed positions. Maximum peak activity of all the agonist muscles occurred throughout a rather wide movement range of the knee joint (80 degrees-150 degrees) in the sitting posture, but the more extended postures tended by lengthening the two-joint muscle of rectus femoris to reduce the range of peak activity of the agonists. During the latter half of the knee extension the activity of the agonists was greatly reduced (p less than .01) and a fully extended knee joint always resulted in silence on the part of the rectus femoris. In that position the vasti muscles together with the semimembranosus formed a force couple for stabilizing the knee joint. The semimembranosus, the two-joint muscle on the antagonistic side, increased activation toward the end of knee extension. This exceptional activation of the antagonist muscle during static agonist effort is likely to be due to the different role of the semimembranosus which tried as an agonist to extend the hip joint in the sitting posture. This phenomenon is supported by the low maximum peak activity of the rectus femoris.(ABSTRACT TRUNCATED AT 250 WORDS)
Article
The knowledge of surface electromyography (SEMG) and the number of applications have increased considerably during the past ten years. However, most methodological developments have taken place locally, resulting in different methodologies among the different groups of users.A specific objective of the European concerted action SENIAM (surface EMG for a non-invasive assessment of muscles) was, besides creating more collaboration among the various European groups, to develop recommendations on sensors, sensor placement, signal processing and modeling. This paper will present the process and the results of the development of the recommendations for the SEMG sensors and sensor placement procedures. Execution of the SENIAM sensor tasks, in the period 1996-1999, has been handled in a number of partly parallel and partly sequential activities. A literature scan was carried out on the use of sensors and sensor placement procedures in European laboratories. In total, 144 peer-reviewed papers were scanned on the applied SEMG sensor properties and sensor placement procedures. This showed a large variability of methodology as well as a rather insufficient description. A special workshop provided an overview on the scientific and clinical knowledge of the effects of sensor properties and sensor placement procedures on the SEMG characteristics. Based on the inventory, the results of the topical workshop and generally accepted state-of-the-art knowledge, a first proposal for sensors and sensor placement procedures was defined. Besides containing a general procedure and recommendations for sensor placement, this was worked out in detail for 27 different muscles. This proposal was evaluated in several European laboratories with respect to technical and practical aspects and also sent to all members of the SENIAM club (>100 members) together with a questionnaire to obtain their comments. Based on this evaluation the final recommendations of SENIAM were made and published (SENIAM 8: European recommendations for surface electromyography, 1999), both as a booklet and as a CD-ROM. In this way a common body of knowledge has been created on SEMG sensors and sensor placement properties as well as practical guidelines for the proper use of SEMG.
Article
Eccentric strength training is thought to be important for improving functional performance. A form of training that may enhance the eccentric training stimulus is the attachment of a rubber bungy to the strength-training apparatus in such a way that the return velocity and, therefore, the force required to decelerate the load at the end of the eccentric phase are increased. To determine the effects of elastic bungy training, we performed two studies. In the first, we examined the electromyographic (EMG) and kinematic characteristics of three different squat techniques: traditional squat, non-bungy jump squat and bungy jump squat. In the second study, we examined whether jump squat training with and without the attachment of a rubber bungy to an isoinertial supine squat machine affects muscle function, multidirectional agility, lunge ability and single leg jump performance. The EMG activity of the vastus lateralis and gastrocnemius muscles was recorded. An instrumented isoinertial supine squat machine was used to measure maximal strength and various force, velocity and power measures in both studies. Participants were randomly assigned to one of three groups: a control group and two weight-trained groups, one of which performed bungy squat jumps and one of which performed non-bungy squat jumps. The two experimental groups performed 10 weeks of ballistic weight training. The kinematic and EMG characteristics of the bungy and non-bungy squat techniques differed significantly from those of the traditional squat on all the variables measured. The only difference between the bungy squat and non-bungy squat training was greater EMG activity during the later stages (70-100%) of the eccentric phase of the bungy squat condition. The 10 weeks of bungy squat and non-bungy squat jump weight training were found to be equally effective in producing improvements in a variety of concentric strength and power measures (10.6-19.8%). These improvements did not transfer to improved performance for the single leg jump and multidirectional agility. However, bungy weight training did lead to a significant improvement in lunge performance (21.5%) compared with the other groups.
Article
Adaptations of arm and thigh muscle hypertrophy to different long-term periodized resistance training programs and the influence of upper body resistance training were examined. Eighty-five untrained women (mean age = 23.1 +/- 3.5 yr) started in one of the following groups: total-body training [TP, N = 18 (3-8 RM training range) and TH, N = 21 (8-12 RM training range)], upper-body training [UP, N = 21 (3-8 RM training range) and UH, N = 19, (8-12 RM training range)], or a control group (CON, N = 6). Training took place on three alternating days per week for 24 wk. Assessments of body composition, muscular performance, and muscle cross-sectional area (CSA) via magnetic resonance imaging (MRI) were determined pretraining (T1), and after 12 (T2) and 24 wk (T3) of training. Arm CSA increased at T2 (approximately 11%) and T3 (approximately 6%) in all training groups and thigh CSA increased at T2 (approximately 3%) and T3 (approximately 4.5%) only in TP and TH. Squat one-repetition maximum (1 RM) increased at T2 (approximately 24%) and T3 (approximately 11.5%) only in TP and TH and all training groups increased 1 RM bench press at T2 (approximately 16.5%) and T3 (approximately 12.4%). Peak power produced during loaded jump squats increased from T1 to T3 only in TP (12%) and TH (7%). Peak power during the ballistic bench press increased at T2 only in TP and increased from T1 to T3 in all training groups. Training specificity was supported (as sole upper-body training did not influence lower-body musculature) along with the inclusion of heavier loading ranges in a periodized resistance-training program. This may be advantageous in a total conditioning program directed at development of muscle tissue mass in young women.
Article
This review focuses on methods for extracting information from the surface EMG recorded in dynamic contractions. It examines the techniques, requirements, and limitations associated with detecting the timing of muscle activation, assessing the modulation of signal amplitude, performing EMG spectral analysis, and estimating conduction velocity. The conclusion is that interpretation of the surface EMG in dynamic tasks requires caution.
Article
The purpose of this investigation was to compare trunk muscle activity during stability ball and free weight exercises. Nine resistance-trained men participated in one testing session in which squats (SQ) and deadlifts (DL) were completed with loads of approximately 50, 70, 90, and 100% of one-repetition maximum (1RM). Isometric contractions during 3 stability ball exercises (quadruped (QP), pelvic thrust (PT), ball back extension (BE)) were also completed. During all exercises, average integrated electromyography (IEMG) from the rectus abdominus (RA), external oblique (EO), longissimus (L1) and multifidus (L5) was collected and analyzed. Results demonstrate that when expressed relative to 100% DL 1RM, muscle activity was 19.5 +/- 14.8% for L1 and 30.2 +/- 19.3% for L5 during QP, 31.4 +/- 13.4% for L1 and 37.6 +/- 12.4% for L5 during PT, and 44.2 +/- 22.8% for L1 and 45.5 +/- 21.6% for L5 during BE. IEMG of L1 during SQ and DL at 90 and 100% 1RM, and relative muscle activity of L5 during SQ and DL at 100% 1RM was significantly greater (P < or = 0.05) than in the stability ball exercises. Furthermore, relative muscle activity of L1 during DL at 50 and 70% 1RM was significantly greater than in QP and PT. No significant differences were observed in RA and EO during any of the exercises. In conclusion, activity of the trunk muscles during SQs and DLs is greater or equal to that which is produced during the stability ball exercises. It appears that stability ball exercises may not provide a sufficient stimulus for increasing muscular strength or hypertrophy; consequently, the role of stability ball exercises in strength and conditioning programs is questioned. SQs and DLs are recommended for increasing strength and hypertrophy of the back extensors.
Article
This study was undertaken to determine whether combined elastic and free weight resistance (CR) provides different strength and power adaptations than free weight resistance (FWR) training alone. Forty-four young (age 20 +/- 1 years), resistance-trained (4 +/- 2 years' experience) subjects were recruited from men's basketball and wrestling teams and women's basketball and hockey teams at Cornell University. Subjects were stratified according to team, then randomly assigned to the control (C; n = 21) or experimental group (E; n = 23). Before and after 7 weeks of resistance training, subjects were tested for lean body mass, 1 repetition maximum back squat and bench press, and peak and average power. Both C and E groups performed identical workouts except that E used CR (i.e., elastic resistance) for the back squat and bench press, whereas the C group used FWR alone. CR was performed using an elastic bungee cord attached to a standard barbell loaded with plates. Elastic tension was accounted for in an attempt to equalize the total work done by each group. Statistical analyses revealed significant (P < 0.05) between-group differences after training. Compared with C, improvement for E was nearly three times greater for back squat (16.47 +/- 5.67 vs. 6.84 +/- 4.42 kg increase), two times greater for bench press (6.68 +/- 3.41 vs. 3.34 +/- 2.67 kg increase), and nearly three times greater for average power (68.55 +/- 84.35 vs. 23.66 +/- 40.56 watt increase). Training with CR may be better than FWR alone for developing lower and upper body strength, and lower body power in resistance-trained individuals. Long-term effects are unclear, but CR training makes a meaningful contribution in the short term to performance adaptations of experienced athletes.
Trunk muscularity in throwers The " sticking period " in a maximum bench press
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  • N Tsunoda
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Tanaka, NI, Komuro, T, Tsunoda, N, Aoyama, T, Okada, M, and Kanehisa, H. Trunk muscularity in throwers. Int J Sports Med 34: 56–61, 2013. 30. van den Tillaar, R and Ettema, G. The " sticking period " in a maximum bench press. J Sports Sci 28: 529–535, 2010.
Conditioning Association Unauthorized reproduction of this article is prohibited. 18 Human strength curves
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Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited. 18. Kulig, K, Andrews, JG, and Hay, JG. Human strength curves. Exerc Sport Sci Rev 12: 417–466, 1984.
The extraction of neural strategies from the surface EMG
  • D Farina
  • R Merletti
  • R M Enoka
Farina, D, Merletti, R, and Enoka, RM. The extraction of neural strategies from the surface EMG. J Appl Physiol (1985) 96: 1486-1495, 2004.
The extraction of neural strategies from the surface EMG
  • Farina