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The artificial pulsed-flows impact associated with hydropower production on the downstream biological and physical processes has been extensively addressed, showing that it may cause fish drift while changing fish habitat selection toward lower water velocity patches, acting as refuge areas. We aimed to evaluate the attraction efficiency of two flow-refuges differing in their approaching angles, for Luciobarbus bocagei at an indoor experimental flume. We tested two flow-refuge insertion angles (45° and 70°), and two flow events (base 7 L/s and pulsed-flow 60 L/s) for each. To analyze flow-refuge efficiency, we quantified fish individual and group patterns, flow-refuge use, and permanence time, while measuring glucose and lactate responses. The results showed that the individual frequency of use during simulated pulsed-flow was higher, especially on the 45° flow-refuge. The simulated pulsed-flow condition did not disrupt group behavior for both approaching angles. Glucose and lactate analysis did not trigger physiological responses in the tested trials. The 45° flow-refuge was used more often than the 70°. The narrowing of the channel caused by the 45° flow-refuge, and the consequent higher flow homogeneity increased the attractiveness of the flow-refuge. Therefore, the flow-refuge insertion angle should be a decisive criterion in the construction and installation of flow-refuges for cyprinids, and be considered a potential indirect mitigation measure. [ABSTRACT FROM AUTHOR]

We analyzed the influence of exercise order using the bench press and squat as the first or second exercise of the session on velocity performance. Ten male trained individuals (20.9 ± 0.7 years) randomly performed two protocols of three sets of six repetitions at 80% of their one-repetition maximum with different exercise sequences: the bench press followed by the squat (BP + S) and the squat followed by the bench press (S + BP). A linear velocity transducer attached to the Smith machine barbell measured the mean propulsive velocity (MPV), peak velocity (PV), and time to peak velocity. Additionally, blood lactate and heart rate were measured. Regarding the bench press, differences were found in the MPV in the first (BP + S: 0.50 ± 0.07 m·s−1 vs. S + BP: 0.42 ± 0.08 m·s−1; p = 0.03, g = 0.72) and second sets (0.50 ± 0.06 m·s−1 vs. 0.42 ± 0.07 m·s−1; p = 0.03, g = 0.73), and in the PV in the second set (0.74 ± 0.09 m·s−1 vs. 0.63 ± 0.09 m·s−1; p = 0.02, g = 0.86). Regarding the squat, although the S + BP sequence tended to show higher velocities, no significant differences were found between protocols. These results showed that squatting first decreased subsequent bench press velocity performance. On the other hand, squat velocity performance was not impaired when preceded by the bench press. [ABSTRACT FROM AUTHOR]

This study aimed to assess the validity and reliability of a commercially available inertial measurement unit (Enode) for measuring barbell kinematics and kinetics during a snatch. In order to assess validity and within- and between-session reliability, thirteen competitive weightlifters conducted two snatches on two separate occasions at 85% of their one-repetition maximum. The Enode sensor was attached to the barbell, with each lift recorded via the device's native application concurrently with an 11-camera motion capture system. Passing–Bablok regression indicated fixed and proportional bias in some horizontal measures of barbell mechanics but showed no bias in all but one vertical variable. Collectively, this suggests that the Enode is a valid tool in the measurement of vertically derived, but not horizontally derived, variables from barbell kinematics. Within- and between-session reliability showed moderate to excellent ICCs, with trivial to small differences between repetitions and between sessions. However, between-session reliability showed lower levels of variability and, thus, may help coaches identify changes in technique over time (between sessions) with good accuracy. Overall the Enode offers a practical and affordable option for coaches seeking to monitor weightlifting technique in training environments. [ABSTRACT FROM AUTHOR]

Barbell squats are commonly utilized in resistance training for rehabilitation, daily living enhancement, and improving sports performance. The current study investigated the kinematic and electromyographic (EMG) parameters in the squat between sexes across different repetition ranges (1-, 3-, 6-, and 10-RM) among recreationally strength-trained subjects. A total of 26 subjects (13 men: age 25 ± 3.5 years, height 178.2 ± 5.8 cm, weight 82.3 ± 9.1 kg; 13 women: age 24 ± 4.1 years, height 165.4 ± 6.3 cm, weight 68.2 ± 8.7 kg) participated in the study. The level of significance was set at p<0.05. The findings revealed no sex-specific differences in average barbell velocity across repetition ranges. However, the 1-RM showed a significantly lower average velocity compared to the final repetition of other repetition ranges (p<0.001), with the last repetition at 10-RM revealing a significantly higher velocity (p<0.001). Women had greater maximal angular hip extension velocity in the final repetitions of the 6- and 10-RM (p≤0.035, ηp2≤0.20), while both sexes displayed lower maximal angular knee extension velocity in the final repetition of the 10-RM (p = 0.028, ηp2 = 0.15). Moreover, men had lower EMG amplitude in the rectus femoris (3- and 10-RM), soleus, and lateral vastus (10-RM) compared to women (p≥0.011, ηp2≥0.26). It was concluded that 10-RM differed greatly in kinematics and EMG, suggesting different fatigue mechanisms compared to other repetition ranges with heavier loads. Furthermore, sex differences in EMG and angular hip extension velocity might imply sex-specific fatiguing mechanisms during high-repetition squats. These considerations could be important when prescribing training programs. [ABSTRACT FROM AUTHOR]

Weightlifting requires explosive strength, high speed, and flexibility. The aim of this research is to present a method based on barbell trajectory and on an anthropometric model comprised of six links for dynamic analysis and optimization of snatch lift. First, snatch lift is divided into nine stages based on barbell trajectory, velocity, and acceleration, while evaluating dynamic characteristics. Then, an anthropometric model of weightlifter which is comprised of six segments: shin, thigh, trunk, upper arm, forearm, and head is developed. Since the head accounts for more or less than 10% of body weight, it should be considered as one link of one degree of freedom. Physical properties such as mass and center of mass of each link are not given by statistical data, but by anthropometry and calculation in Solidworks program. Finally, for barbell trajectory as one of the most important performance indices in weightlifting, an optimal control problem is formulated to minimize a criterion function defined as the sum of work done by lifter during snatch lift and solved by using Pontryagin Maximum Principle (PMP). The proposed method is illustrated with case study, showing results in good agreement with ones by analysis of lifter's actual performances. It can help coach or weightlifter to improve the snatch technique. [ABSTRACT FROM AUTHOR]

The electric solar wind sail (E-sail) is a new propellant-free propulsion concept. The under-actuated and highly nonlinear features of E-sail systems pose a great challenge to their attitude controller design. Conventional control schemes may not be capable of dealing with this tough problem. To this end, a reinforcement learning (RL)-based control scheme, which can explore and obtain optimal policies in the absence of training datasets, is proposed for the attitude control of a barbell E-sail system. The barbell E-sail comprises two end satellites linked to an insulated confluence point through long and conductive tethers. The voltages of the two tethers can be individually modulated for attitude control. The system attitude dynamics is described using a nonsingular formulation. The control scheme has a two-stage design. In the first stage, an RL controller based on the Proximal Policy Optimization (PPO) algorithm is used to obtain an RL control strategy, which is emulated and updated by neural networks. In the second stage, the attitude feedback control is accomplished with low computation and energy consumption and fast convergence speed by performing a real-time mapping from the system state to the control output using the updated control strategy. Finally, the simulation results demonstrate that the proposed RL-based control scheme can effectively adjust the E-sail to the design attitude by regulating the tether voltage difference. The comparisons with the NMPC scheme also indicate that the developed control scheme can significantly reduce the computation time with control accuracy maintained. • Nonlinear dynamics and inherent constraints of the E-sail system are accounted for. • The reinforcement learning method is first applied to attitude control of the E-sail system. • Easy implementation, low computational cost and wide-range attitude adjustment are achieved. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine the differences in braking and propulsion force-time characteristics and barbell velocity between traditional (TRAD) and accentuated eccentric loaded (AEL) back squats using various load combinations. Sixteen resistance-trained men participated in four separate testing sessions which included a one repetition maximum (1RM) back squat during the first session and three squat testing sessions. During the squat testing sessions, participants either performed sets of three repetitions of TRAD back squats each with 50, 60, 70, and 80% 1RM or performed the same loads with the addition of weight releasers that increased the total eccentric weight of the first repetition of each set to either 100 (AEL-MAX) or 110% 1RM (AEL-SUPRA). Braking and propulsion mean force, duration, and impulse as well as mean and peak barbell velocity were compared between each condition and load. Significantly greater braking impulses were produced during the AEL-MAX and AEL-SUPRA conditions compared to TRAD (p < 0.03) with small-moderate effect sizes favoring AEL-SUPRA. No other significant differences existed among conditions for other braking, propulsion, or barbell velocity variables. AEL-MAX and AEL-SUPRA back squats may provide a greater braking stimulus compared to TRAD squats; however, the propulsion phase of the movement does not appear to be impacted. From a loading standpoint, larger and smaller load spreads may favor rapid and maximal force production characteristics, respectively. Further research on this topic is needed as a large portion of the braking stimulus experienced during AEL back squats may be influenced by relative strength. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This study compared the acute effects of different ranges of motion (ROM) on fatigue and metabolic responses during repeated sets of bench press exercise. Ten resistance trained men performed three sets to momentary failure with two-min rest intervals at three different ROM: full ROM (FULL), and partial ROM in which the barbell was moved either at the bottom half (BOTTOM) or the top half (TOP) of the full barbell vertical displacement. In TOP, a higher load was lifted, and a higher total number of repetitions was performed compared to FULL and BOTTOM (130 ± 17.6 vs. 102.5 ± 15.9 vs. 98.8 ± 17.5 kg; 55.2 ± 9.8, 32.2 ± 6.5 vs. 49.1 ± 16.5 kg, respectively p < 0.01). Work per repetition was higher in FULL than TOP and BOTTOM (283 ± 43 vs. 205 ± 32 vs. 164 ± 31 J/repetition, p < 0.01). Mean barbell velocity at the start of set 1 was 21.7% and 12.8% higher in FULL compared to TOP and BOTTOM, respectively. The rate of decline in mean barbell velocity was doubled from set 1 to set 3 (p < 0.01) and was higher in FULL than both TOP and BOTTOM (p < 0.001). Also, the rate of mean barbell velocity decline was higher in BOTTOM compared to TOP (p = 0.045). Blood lactate concentration was similarly increased in all ROM (p < 0.001). Training at TOP ROM allowed not only to lift a higher load, but also to perform more repetitions with a lower rate of decline in mean barbell velocity. Despite the lower absolute load and work per repetition, fatigue was higher in BOTTOM than TOP and this may be attributed to differences in muscle length. [ABSTRACT FROM AUTHOR]

The accumulation of liquid in gas wells is a common problem in the later stages of shale gas production. The plunger lift is currently one of the most economically effective methods for removing accumulated liquid in gas wells, but its applicability is not yet clear. This article analyzes the production characteristics of gas wells on-site and summarizes the key indicators for evaluating the plunger lift technology, including casing pressure changes, production changes, liquid column plunger height, tubing-casing pressure differential changes, and differential size of pressure relief. Combined with numerical simulation methods, a complete set of evaluation systems for judging, classifying, and evaluating the effectiveness of plunger lift technology is established, and an evaluation method for the applicability of plunger lift technology is proposed. Taking well Ning 216-H4 as an example, a comprehensive evaluation is made on whether the gas well is suitable for plunger lift based on the height of the liquid column above the plunger, the production effect under pressure, and the overall shut-in time. This method has important guiding significance for the further promotion and application of plunger lift technology in deep wells, directional wells, and horizontal wells to achieve efficient development of natural gas. [ABSTRACT FROM AUTHOR]

Study purpose. This study aimed to determine the relationship between kicking speed performance and different stance widths during barbell hip thrust (BHT) at one repetition maximum (1RM) scores among young elite Silat athletes. Materials and methods. 15 male and 15 female Silat athletes with at least one year of resistance training experience and a mean age of 21.3 ± 1.2 years participated in this study. The load indicator performance associated with kicking performance was measured using 1RM load during BHT at varying stance widths. The data was analyzed using Pearson correlation tests through the SPSS Version 25 application. Results. A significant correlation was found between stance width, physical characteristics, and performance metrics with a low to moderate relationship. For physical features, weight (r = 0.43, p < 0.05), height (r = 0.64, p < 0.05), and leg length (r = 0.44, p < 0.05) show positive relationship. Low to moderate significant relationships were found during WSW-RFK (r = 0.39, p < 0.05) regarding 1RM and kicking performance. No significant correlations were found between NSW or NRW and the observed variables, except for a negative correlation between NRW and strength (r = -0.43, p < 0.05). There was a significant difference between males vs. females in RFK-NSW, RFK (p = 0.006, p < 0.05), and LFK-NRW (p = 0.001, p < 0.05) in kicking performance. Conclusions. This study revealed that stance width in barbell hip thrusts moderately correlates with physical characteristics and performance in young elite Silat athletes, where wider stances align with physical characteristics and narrower stances align with lower kicking performance. It also highlighted the importance of personalized training due to observed gender differences in kicking speed. [ABSTRACT FROM AUTHOR]

Study purpose. Examining the physiological and physical effects of Tabata training with Kempo sports movement techniques. Materials and methods. The study participants were 16 adolescents divided into two distinct groups: the Tabata group and the non-Tabata group. The training was conducted for 6 weeks, 3 times per week, with each session lasting 2 hours. The training components for kicks and punches included Gyaku Geri, Jun Mawashi Geri, Jun Zuki, and Gyaku Mawashi Geri. Each teenager did physical exercise once a week for 2 hours. A normality test (Shapiro-Wilk) was used to assess the normality of the data. A Two-Way ANOVA with a significance level of less than 0.05 was conducted to examine the difference in means between the two groups. Furthermore, the researchers also tested the N-Gain Score to assess the effectiveness of the 6-week Tabata training program. All tests were conducted using SPSS version 23 and GraphPad Prisma version 10 for graph creation. Results. The statistics indicate that a 6-week training with Tabata can effectively reduce resting heart rate and improve Standing Broad Jump (SBJ) performance by a value of sig. <0.05. In the pretest-posttest difference test within the group, the results show sig. <0.05. The results of the N-Gain Score test show that Kempo training using the Tabata method is effective in reducing resting heart rate by up to 88%, but is not effective in increasing power (SBJ) by a value of 10%. Conclusions. The study revealed that incorporating the Tabata method into Kempo training, with necessary adjustments for 6 weeks, led to a notable reduction in resting heart rate. A decrease in resting heart rate is a dependable indicator of the advancement in physical fitness and general well-being in adolescents. [ABSTRACT FROM AUTHOR]

Introduction. Appositional bone augmentation is considered a challenging surgical problem to correct for the deficient alveolar ridge. To overcome this challenge, a novel concept was recently published called "Barbell Technique." This technique has been used more commonly for horizontal bone augmentation. To our knowledge, this is the first report on using the Barbell Technique for vertical bone augmentation. Case Report. This report describes and demonstrates the clinical feasibility of the use of this concept in the reconstruction of a tridimensional alveolar ridge defect in the anterior maxilla. Due to the severity of the defect, both hard and soft tissue deficiencies required augmentation. The first surgery involved a soft tissue grafting procedure while in the second surgical procedure, hard tissue augment was performed using the Barbell device to provide both vertical and horizontal support for the hard tissue graft. The donor material consisted of equal volume of xenograft and autogenous bone used to fill the defect and covered with a collagen barrier membrane. After a healing period of 9 months, the site was reopened. Bone formation clinically verified the correction of alveolar bone contour and volume permitted placement of two titanium implants after the removal of Barbell device. Conclusion. This case report demonstrates successful vertical and horizontal bone augmentation of a critical size defect in the anterior maxilla, correcting both hard and soft tissue contours, and providing the tissues needed to support dental implants in the anterior maxilla. [ABSTRACT FROM AUTHOR]

This study investigated the effects of the squat exercise combined with using barbells and elastic bands on muscle strength, body composition, and balance in working age men. A total of 24 men in working age between 18 and 39 years were randomly selected into 3 Groups using systematic sampling: (a) Combined Training using Elastic Band Weight at 35% (n = 7); (b) Combined Training using Elastic Band Weight at 20% (n = 8); and (c) Control Group (n = 9). The 2 Treatment Groups trained twice per week for 8 weeks. For each training session, squats combined with using elastic band repetitions per set of 4 sets (80% one-repetition maximum [1RM]) were performed in 0-4 weeks and (85% 1RM) in 5-8 weeks. Before and after 8 weeks of training, the participants were tested using the 1RM squat (SQ), Balance Error Score System (BESS), Vertical Jump Reach Test (VJT), and Body Composition. An analysis of the paired t-test revealed that the SQ, BESS, and VJT scores were significantly higher after training in the 2 Treatment Groups (P < 0.05). An analysis of covariance revealed that the SQ and BESS scores were significantly higher than those of the Control Group (P < 0.05). No significant differences were detected between the 2 Treatment Groups. The results suggest that combining barbell and elastic band exercise increases strength, balance, and power, and combined training with using a band among those who never performed resistance exercise via an applied load of bands that can be used to replace other weights. [ABSTRACT FROM AUTHOR]

The technology for human activity recognition has diverse applications within the Internet of Things spectrum, including medical sensing, security measures, smart home systems, and more. Predominantly, human activity recognition methods have relied on contact sensors, and some research uses inertial sensors embedded in smartphones or other devices, which present several limitations. Additionally, most research has concentrated on recognizing discrete activities, even though activities in real-life scenarios tend to be continuous. In this paper, we introduce a method to classify continuous human activities, such as walking, running, squatting, standing, and jumping. Our approach hinges on the micro-Doppler (MD) features derived from continuous-wave radar signals. We first process the radar echo signals generated from human activities to produce MD spectrograms. Subsequently, a bidirectional gate recurrent unit (Bi-GRU) network is employed to train and test these extracted features. Preliminary results highlight the efficacy of our approach, with an average recognition accuracy exceeding 90%. [ABSTRACT FROM AUTHOR]

Background: Velocity-based training (VBT) requires measurement of the velocity at which the barbell is moved in the concentric phase with regard to different resistance exercises, which provides accurate, indirect estimations of 1 RM. However, for assessing punch performance, no study has been carried out to date. The purpose of this study was to analyse the reliability of the GymAware linear transducer for the measurement of barbell velocity during the landmine push throw (LPT) test using four loads. Methods: Twenty-five healthy, physically active male students, aged 24.13 ± 2.82 years, volunteered to take part in this study. The reliability of the LPT test was measured at two separate visits, with a 2-day interval between them. One series of the test protocol included four parts of the LPT test with progressively increasing loads (20, 25, 30, and 35 kg) and 5 min intervals for rests between loads. Results: For all four loads, excellent intra-rater and test–retest reliability was noted for the mean force variable (ICC = 0.97–0.99). Additionally, very strong and significant correlations were established between measurements (r = 0.96–0.99). Poor reliability was observed for barbell height and total work (ICC below 0.5). A trend of decreasing reliability was detected with increasing barbell load. Furthermore, measurements without the barbell throw were more reliable than those with it. Conclusions: These results support the use of the GymAware linear transducer to track barbell velocity during the LPT test. This device may have valuable practical applications for strength and conditioning coaches. Therefore, we suggest that the LPT assessed with the GymAware linear transducer may be a useful method for evaluating upper limb strength and power during boxing punches. [ABSTRACT FROM AUTHOR]

The aim of this paper is to present new properties of captive domination and determine the number of some graphs. The proper subset of the vertices of a graph G is a captive dominating set if it is a total dominating set and each vertex in this set dominates at least one vertex which does not belong to the dominating set. The domination number γ(G) is the minimum cardinality of a dominating set D of G. If V-D contains a dominating set, then this set is called an inverse set of D in G. The symbol γ-1 (G) represents the minimum cardinality over all inverse dominating set of G. Some graphs which determine the captive domination number such as a ladder graph, corona graph of two paths, lollipop graph, barbell graph, corona graph of a cycle of order n, and null graph of order p and helm graph. For all these graphs and complements the captive domination and inverse captive domination are calculated. [ABSTRACT FROM AUTHOR]

Introduction: Range of motion (ROM) of resistance exercise affects the muscle damage magnitude and the recovery-time course. Thus, the main aim of this study was to compare conventional and extended ROM in the bench press exercise on neuromuscular fatigue assessed by velocity changes during bench press throw, as well on the exercise-induced muscle damage evaluated by creatine kinase (CK) activity in the blood. Material and Methods: A total of fourteen healthy, welltrained males performed 5 sets of the bench press exercise at 70% of one repetition maximum with either standard (STD) and cambered (CMB) barbell until reaching volitional failure. CK and barbell velocity changes were assessed at the baseline and 1h, 24h, 48h post exercise protocol. Results: The results showed that higher peak barbell velocity was reached during the bench press throw after the CMB when compared to the STD condition. Moreover, CK activity showed an overall significant growing trend from baseline to time points following exercise during the STD, whereas the CMB post-48h CK was higher in comparison to pre and post, but not than post-24h. Conclusion: the bench press exercise performed with the use of CMB barbell might not require a specific training approach, and even higher training frequency might be applied. [ABSTRACT FROM AUTHOR]

Maximal barbell power output (Pmax) and vertical barbell threshold velocity (vthres) are major determinants of weightlifting performance. Moreover, an optimal force-velocity relationship (FvR) profile is an additional variable that has the potential to maximize sports performance. The aims of this study were (i) to present a biomechanical model to calculate an optimal FvR profile for weightlifting, and (ii) to determine how vthres, Pmax, and the optimal FvR profile influence theoretical snatch performance (snatchth). To address these aims, simulations were applied to quantify the respective influence on snatchth. The main findings confirmed that at constant vthres and Pmax, snatchth is maximized at an optimal FvR profile. With increasing Pmax and decreasing vthres, the optimal FvR profile becomes more force dominated and more effective to enhance snatchth. However, sensitivity analysis showed that vthres and Pmax have a larger effect on snatchth than the optimal FvR profile. It can be concluded that in weightlifting, training protocols should be designed with the goal to improve Pmax and to reduce vthres to ultimately enhance snatchth. Training programs designed to achieve the optimal FvR profile may constitute an additional training goal to further develop weightlifting performance in elite athletes that already present high Pmax levels. [ABSTRACT FROM AUTHOR]

This paper presents a 220 GHz × 2 amplifier–doubler chain composed of a rat-race balun, a 6-stage driver amplifier, and a frequency doubler. The presented amplifier–doubler chain was fabricated in commercial 40 nm bulk CMOS technology. The maximum cutoff frequency fmax for the NMOS transistor produced by this manufacturing process was 290 GHz. The saturation output power of the six-stage driver amplifier at 110 GHz was 11.5 dBm. The transistor of the frequency doubler consisted of a single-row interleaved Poly-Diffusion Contact balancing structure. Theoretically, the single-row interleaved Poly-Diffusion Contact balancing structure was able to effectively avoid parasitic components. The simulated results demonstrate that the presented structure achieves a higher output than the conventional designs. Based on these measured results, the presented amplifier–doubler chain provides a peak output power of 7.9 dBm at 200 GHz and a 3-dB bandwidth of 30 GHz. Based on the comparison with other reported results, the presented amplifier–doubler chain provides the highest output power among reported frequency doublers fabricated in CMOS technology. [ABSTRACT FROM AUTHOR]

Differential fault attack (DFA) is a distinctive methodology for acquiring the key to block ciphers, which comprises two distinct strategies: DFA on the state and DFA on the key schedule. Given the widespread adoption of the Advanced Encryption Standard (AES), it has emerged as a prominent target for DFA. This paper presents an efficient DFA on the AES, utilizing a two−byte fault model that induces faults at the state with discontiguous rows. The experiment demonstrates that, based on the proposed fault model, the key for AES–128, AES–192, and AES–256 can be successfully recovered by exploiting two, two, and four faults, respectively, without the need for exhaustive research. Notably, in the case of AES–256, when considering exhaustive research, two (or three) faults are needed with 232 (or 216) exhaustive searches. In comparison to the currently available DFA on the AES state, the proposed attack method shows a higher efficiency due to the reduced induced faults. [ABSTRACT FROM AUTHOR]

Background: There is no clear agreement regarding the ideal rest interval and training intensity to optimize post-activation performance enhancement (PAPE) after barbell squat (BS). Therefore, the aim of this study was to investigate the effects of rest interval and training intensity on jumping performance due to PAPE. Methods: Searches were performed in PubMed, Web of Science, and EBSCO databases. We included studies that satisfied the following criteria: (1) eligible studies should be randomized controlled trials; (2) eligible studies should investigate the acute effect of barbell squat-induced PAPE on jump performance; (3) eligible studies should use countermovement jump, squat jump, or vertical jump as the outcome measure. Results: From 2518 search records initially identified, 19 studies were eligible for meta-analysis. Our meta-analysis results showed that BS had no significant effect on improving jumping performance due to PAPE (Cohen’s d = 0.09, p = 0.08). Subgroup analysis showed that rest interval between 0–1 min was detrimental to jumping performance (Cohen’s d = −0.33, p < 0.01), while rest intervals between 4–7 min (Cohen’s d = 0.31, p < 0.01) and 8-9 min (Cohen’s d = 0.26, p = 0.02) provided favorable jumping performance outcomes. In addition, low-intensity and moderate-intensity BS had no significant effect on jump performance, while high-intensity BS showed results consistent with rest interval. Conclusion: Our study indicated that both low-intensity and moderate-intensity BS failed to induce PAPE, and it is recommended that future studies use high-intensity BS to induce PAPE. A rest interval of 4–9 min had a beneficial impact on jump height, and an interval range of 4–7 min seems to be the best rest interval between conditioning activity and jumping performance. [ABSTRACT FROM AUTHOR]

Velocity-based training (VBT) is a method to monitor resistance training based on measured kinematics. Often, measurement devices are too expensive for non-professional use. The purpose of this study was to determine the accuracy and precision of the Apple Watch 7 and the Enode Pro device for measuring mean, peak, and propulsive velocity during the free-weighted back squat (in comparison to Vicon as the criterion). Velocity parameters from Vicon optical motion capture and the Apple Watch were derived by processing the motion data in an automated Python workflow. For the mean velocity, the barbell-mounted Apple Watch (r = 0.971–0.979, SEE = 0.049), wrist-worn Apple Watch (r = 0.952–0.965, SEE = 0.064) and barbell-mounted Enode Pro (r = 0.959–0.971, SEE = 0.059) showed an equal level of validity. The barbell-mounted Apple Watch (Vpeak: r = 0.952–0.965, SEE = 0.092; Vprop: r = 0.973–0.981, SEE = 0.05) was found to be the most valid for assessing propulsive and peak lifting velocity. The present results on the validity of the Apple Watch are very promising, and may pave the way for the inclusion of VBT applications in mainstream consumer wearables. [ABSTRACT FROM AUTHOR]

When performing the traditional barbell back squat, athletes may experience discomfort in the shoulders or be limited by shoulder mobility. The Squatbar® is a barbell designed to be ergonomic to the shoulders but has never, in the scientific literature, been compared to the traditional Olympic barbell. Thus, the current study investigated kinematics, kinetics, and myoelectric activity (EMG) between the Squatbar® barbell and the Olympic barbell when performing a one-repetition maximum (1-RM) back squat. Twelve strength-trained men (body mass: 83.5 ± 7.8 kg, age: 27.3 ± 3.8 years, height: 180.3 ± 6.7 cm) performed a 1-RM squat with both the Olympic and Squatbar® barbells. The paired samples t-test revealed significantly more weight was lifted with the Olympic barbell compared to the Squatbar® barbell (148 ± 21 kg vs. 144.5 ± 20 kg) and was accompanied by greater shoulder external rotation (74 ± 7.5° vs. 59.6 ± 9.2°). No differences in joint kinematics of the lower limbs, kinetics, or EMG were observed between the two barbells. The results of the current study indicate the Squatbar® to be a suitable substitution for the Olympic barbell for athletes with reduced shoulder mobility when performing the squat. It was concluded that the Squatbar® induces similar kinetics, kinematics, and EMG when compared to the Olympic barbell, except for reducing external rotation of the shoulder. [ABSTRACT FROM AUTHOR]

The objective of this study was to compare the impact of cambered and standard barbells used during the bench press exercise on the number of performed repetitions and mean velocity during a bench press training session that included 5 sets performed to volitional failure at 70% of one-repetition maximum (1RM) (for each barbell type). An additional objective was to determine whether there would be any difference in neuromuscular fatigue assessed by peak velocity changes during bench press throws performed 1 and 24 hours after the cessation of each session. The research participants included 12 healthy resistance-trained men. Participants performed 5 sets of the bench press exercise to volitional failure against 70% of 1RM with the cambered or standard barbell. The Friedman's test showed an overall trend of a significant decrease in the mean velocity (p < 0.001) and a number of performed repetitions (p < 0.001) from the first to the fifth set (p < 0.006 and p < 0.02, respectively for all) under both conditions, yet neither bar showed significant differences between the corresponding sets. Two-way ANOVA indicated a significant main effect of time (p < 0.001) for peak velocity during the bench press throw. The post-hoc comparisons showed significantly lower peak velocity during the bench press throw one hour after the bench press compared to pre (p = 0.003) and 24-hour post intervention (p = 0.007). Both barbells caused a similar decrease in peak barbell velocity during the bench press throw performed one hour after the bench press training session, with values returning to baseline 24 hours later. This indicates that bench press workouts with either a standard or a cambered barbell present the same training demands. [ABSTRACT FROM AUTHOR]

Still rings are a unique gymnastics apparatus allowing for a combination of dynamic and static elements in a specific technique. This review aimed to compile the dynamic, kinematic, and EMG characteristics of swing, dismount, handstand, strength, and hold elements on still rings. This systematic review was conducted in concordance with PRISMA in PubMed, EBSCOhost, Scopus, and Web of Science databases. In total, 37 studies were included, describing the strength and hold elements, the kip and swing elements, swing through or to handstand, and dismounts. The current evidence suggests that the execution of gymnastics elements on still rings and training drills requires a high training load. Specific preconditioning exercises could be used to train for the Swallow, iron cross, and support scale. Negative impacts of load during hold elements can be reduced by special support devices such as the Herdos or support belts. Another aspect is improving strength prerequisites by exercises such as bench presses, barbell exercises, and support belts, where the main focus should be on muscular coordination similar to the other considerable elements. Electromyography is an appropriate tool for the investigation of muscular coordination and force platforms for assessing a sufficient strength level to successfully perform elements on still rings. [ABSTRACT FROM AUTHOR]

A new species of sisorid catfish of the genus Euchiloglanis is described from the Gam River, a tributary of the Red River in northern Vietnam. Euchiloglanis nami sp. n. differs from all the species placed in Euchiloglanis and Chimarrichthys by having elongated papilae on the ventral part of maxillary barbell. Euchiloglanis nami is distinguished from E. longibarbatus by having a wider premaxillary tooth band without indentation and the tip of the maxillary barbell reaching pectoral fin origin. The new species differs from E. davidi and E. kishinouyei by the depth of the caudal peduncle equal to 20.26–27.40 % of the caudalpeduncle length. It also differs from E. dorsoarcus by the anal-fin position being closer to the caudal-fin base than to the pelvic fin. From E. phongthoensis, it differs by the distance from the adipose-fin origin to the dorsal-fin insertion close to 50 % of the length of the adipose-fin base. In addition, E. nami differs from E. longus by having a wider premaxillary tooth band without indentation, shorter caudal peduncle (20.7 % SL), higher caudal peduncle depth (5.0 % SL), shorter distance between dorsal-fin insertion to adiposefin origin (14.8 % SL), shorter distance from snout to adipose-fin origin (57.4 % SL), shorter pelvic fins length (15.9 % SL) reaching the anus or a little beyond anus, longer adipose-fin base length (33.2 % SL) and narrower interorbital width (24.6 % SL). The new species is the first record of the genus Euchiloglanis in the Gam-Lo River system and is the third species in the genus from Vietnam. [ABSTRACT FROM AUTHOR]

This study examined the reliability, potential bias, and practical differences between the GymAware Powertool (GA), Tendo Power Analyzer (TENDO), and Push Band 2.0 (PUSH) during the jump shrug (JS) and hang high pull (HHP) performed across a spectrum of loads. Fifteen resistancetrained men performed JS and HHP repetitions with 20, 40, 60, 80, and 100% of their 1RM hang power clean, and mean (MBV) and peak barbell velocity (PBV) were determined by each velocity measurement device. Least-products regression and Bland–Altman plots were used to examine instances of proportional, fixed, and systematic bias between the TENDO and PUSH compared to the GA. Hedge’s g effect sizes were also calculated to determine any meaningful differences between devices. The GA and TENDO displayed excellent reliability and acceptable variability during the JS and HHP while the PUSH showed instances of poor–moderate reliability and unacceptable variability at various loads. While the TENDO and PUSH showed instances of various bias, the TENDO device demonstrated greater validity when compared to the GA. Trivial–small differences were shown between the GA and TENDO during the JS and HHP exercises while trivial–moderate differences existed between GA and PUSH during the JS. However, despite trivial–small effects between the GA and PUSH devices at 20 and 40% 1RM during the HHP, practically meaningful differences existed at 60, 80, and 100%, indicating that the PUSH velocity outputs were not accurate. The TENDO appears to be more reliable and valid than the PUSH when measuring MBV and PBV during the JS and HHP. [ABSTRACT FROM AUTHOR]

The present study investigated the excitation of the biceps brachii and anterior deltoid during bilateral biceps curl performed using the straight vs. EZ barbell and with or without EZflexing the arms. Ten competitive bodybuilders performed bilateral biceps curl in non-exhaustive 6-rep sets using 8-RM in four variations: using the straight barbell EZflexing (STEZflex) or not EZflexing the arms (STno-EZflex) or the EZ barbell EZflexing (EZEZflex) or not EZflexing the arms (EZno-EZflex). The ascending and descending phases were separately analyzed using the normalized root mean square (nRMS) collected using surface electro-myography. For the biceps brachii, during the ascending phase, a greater nRMS was observed in STno-EZflex vs. EZno-EZflex (+1.8%, effect size [ES]: 0.74), in STEZflex vs. STno-EZflex (+17.7%, ES: 3.93) and in EZEZflex vs. EZno-EZflex (+20.3%, ES: 5.87). During the descending phase, a greater nRMS was observed in STEZflex vs. EZEZflex (+3.8%, ES: 1.15), in STno-EZflex vs. STEZflex (+2.8%, ES: 0.86) and in EZno-EZflex vs. EZEZflex (+8.1%, ES: 1.81). The anterior deltoid showed distinct excitation based on the arm EZflexion/no-EZflexion. A slight advantage in biceps brachii excitation appears when using the straight vs. EZ barbell. Flexing or not EZflexing the arms seems to uniquely excite the biceps brachii and anterior deltoid. Practitioners should consider including different bilateral biceps barbell curls in their routine to vary the neural and mechanical stimuli. [ABSTRACT FROM AUTHOR]

Traditionally, the biomechanical analysis of Olympic weightlifting movements required laboratory equipment such as force platforms and transducers, but such methods are difficult to implement in practice. This study developed a field-based method using wearable technology and videos for the biomechanical assessment of weightlifters. To demonstrate the practicality of our method, we collected kinetic and kinematic data on six Singapore National Olympic Weightlifters. The participants performed snatches at 80% to 90% of their competition one-repetition maximum, and the three best attempts were used for the analysis. They wore a pair of in-shoe force sensors loadsol® (novel, Munich, Germany) to measure the vertical ground reaction forces under each foot. Concurrently, a video camera recorded the barbell movement from the side. The kinematics (e.g., trajectories and velocities) of the barbell were extracted using a free video analysis software (Kinovea). The power–time history was calculated from the force and velocity data. The results showed differences in power, force, and barbell velocity with moderate to almost perfect reliability. Technical inconsistency in the barbell trajectories were also identified. In conclusion, this study presented a simple and practical approach to evaluating weightlifters using in-shoe wearable sensors and videos. Such information can be useful for monitoring progress, identifying errors, and guiding training plans for weightlifters. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare the propulsion phase characteristics of the jump squat (JS), hexagonal barbell jump (HEXJ), and jump shrug (JShrug) performed across a spectrum of relative loads. Thirteen resistance-trained women (18–23 years old) performed JS, HEXJ, and JShrug repetitions at body mass (BM) or with 20, 40, 60, 80, or 100% BM during three separate testing sessions. Propulsion mean force (MF), duration (Dur), peak power output (PP), force at PP (FPP), and velocity at PP (VPP) were compared between exercises and loads using a series of 3 × 6 repeated measures ANOVA and Hedge's g effect sizes. There were no significant differences in MF or Dur between exercises. While load-averaged HEXJ and JShrug PP were significantly greater than the JS, there were no significant differences between exercises at any individual load. The JShrug produced significantly greater FPP than the JS and HEXJ at loads ranging from BM–60% BM, but not at 80 or 100% BM. Load-averaged VPP produced during the JS and HEXJ was significantly greater than the JShrug; however, there were no significant differences between exercises at any individual load. Practically meaningful differences between exercises indicated that the JShrug produced greater magnitudes of force during shorter durations compared to the JS and HEXJ at light loads (BM–40%). The JS and HEXJ may be classified as more velocity-dominant exercises while the JShrug may be more force-dominant. Thus, it is important to consider the context in which each exercise is prescribed for resistance-trained women to provide an effective training stimulus. [ABSTRACT FROM AUTHOR]

The purpose of this investigation was to compare concentric movement velocity (CMV) measured with the PUSH Band (v2.0) and a Vicon motion capture system (MC) during the back squat (SQ) and the bench press (BP) resistance exercises (RE). Twelve resistance-trained males (26.0 ± 5.5 years; 175.6 ± 4.9 cm; 96.3 ± 15.8 kg) completed ten repetitions at 50% of one-repetition maximum (1RM), and six repetitions at 75% 1RM for both BP and SQ. Four PUSH devices were utilized and attached to the subject's right forearm, the center barbell, left and right sides of the barbell. MC markers were placed on top of each PUSH device. An overall analysis using a series of least-squares means contrasts suggested CMV did not differ (p > 0.05) between measurement technologies when position, RE, intensity and repetitions were combined. PUSH exhibited the highest Intraclass Correlation Coefficients (ICC = 0.835–0.961) and Pearson Product-Moment Correlation Coefficients (r = 0.742–0.949) at the arm and center barbell locations when compared with MC. The measurement of CMV between MC and PUSH compares favorably during moderate (i.e., 50%) and high (75%) intensity SQ and BP RE. These data indicate individuals can use the PUSH band v2.0 to accurately monitor CMV within a RE set for SQ and BP RE. [ABSTRACT FROM AUTHOR]

Current technologies based on inertial measurement units (IMUs) are considered valid and reliable tools for monitoring barbell velocity in strength training. However, the extracted outcomes are often limited to a few velocity metrics, such as mean or maximal velocity. This study aimed at validating a single IMU-based methodology to automatically obtain the barbell velocity full profile as well as key performance metrics during maximal Paralympic bench press. Seven Paralympic powerlifters (age: 30.5 ± 4.3 years, sitting height: 71.6 ± 6.8 cm, body mass: 72.5 ± 16.4 kg, one-repetition maximum: 148.4 ± 38.6 kg) performed four attempts of maximal Paralympic bench press. The barbell velocity profile and relevant metrics were automatically obtained from IMU linear acceleration through a custom-made algorithm and validated against a video-based reference system. The mean difference between devices was 0.00 ± 0.04 m·s−1 with low limits of agreement (<0.09 m·s−1) and moderate-to-good reliability (ICC: 0.55–0.90). Linear regression analysis showed large-to-very large associations between paired measurements (r: 0.57–0.91, p < 0.003; SEE: 0.02–0.06 m·s−1). The analysis of velocity curves showed a high spatial similarity and small differences between devices. The proposed methodology provided a good level of agreement, making it suitable for different applications in barbell velocity monitoring during maximal Paralympic bench press. [ABSTRACT FROM AUTHOR]

Objective: The intensity of barbell bench press exercise is generally prescribed as the load to be lifted for a specific number of repetitions; however, other factors (e.g., execution velocity) can affect bench press exercise intensity. Moreover, no study assessed whether load distribution (i.e., the distance between the disc stacks on the two sides of the barbell) affects exercise intensity. The present study aims to assess how different combinations of load, velocity, and barbell load distribution affect the number of repetitions to failure (REPfailure), and rating of perceived exertion (RPEfatigue) and number of repetitions (REPfatigue) at fatigue onset. Methods: Ten males (age 23.3±1.8 years) performed bench press exercises to exhaustion using random combinations of three loads (50%, 65%, and 80% of 1 repetition maximum), three execution velocities (50%, 70%, and 90% of maximal concentric velocity), and two load distributions (narrow and wide). Three separate three-way repeated-measures ANOVAs were performed to assess the effect of load, velocity, and load distribution on REPfailure, RPEfatigue, and REPfatigue expressed as a percentage of REPfailure. Results: REPfailure was affected by load (p<0.001), velocity (p<0.001), and distribution (p = 0.005). The interactions between load and velocity (p<0.001) and load and distribution (p = 0.004) showed a significant effect on REPfailure, whereas the interaction between velocity and distribution was not significant (p = 0.360). Overall, more REPfailure were performed using lower loads, higher velocities, and a wider distribution. RPEfatigue and REPfatigue were affected by load (p<0.001 and p = 0.007, respectively) and velocity (p<0.001 and p<0.001, respectively), and not by distribution (p = 0.510 and p = 0.571, respectively) or the two-way interaction effects. Overall, using higher loads yielded higher RPEfatigue but lower REPfatigue, while RPEfatigue and REPfatigue were higher when slower velocities were used. Conclusion: The current investigation shows that not only load but also velocity and barbell load distribution may influence bench press training volume and perceived exertion. [ABSTRACT FROM AUTHOR]

The purpose of this study was to improve our understanding of the relative contributions of biomechanical, anthropometric, and psychological factors in explaining maximal bench press (BP) strength in a heterogeneous, resistance-trained sample. Eighteen college-aged participants reported to the laboratory for three visits. The first visit consisted of psychometric testing. The second visit assessed participants' anthropometrics, additional psychometric outcomes, and bench press one repetition maximum (1RM). Participants performed isometric dynamometry testing for horizontal shoulder adduction and elbow extension at a predicted sticking point joint position. Multiple linear regression was used to examine the relationships between the biomechanical, anthropometric, and psychological variables and BP 1RM. Our primary multiple linear regression accounted for 43% of the variance in BP strength (F(3,14) = 5.34, p = 0.01; R2 = 0.53; adjusted R2 = 0.43). The sum of peak isometric net joint moments from the shoulder and elbow had the greatest standardized effect (0.59), followed by lean body mass (0.27) and self-efficacy (0.17). The variance in BP 1RM can be similarly captured (R2 = 0.48) by a single principal component containing anthropometric, biomechanics, and psychological variables. Pearson correlations with BP strength were generally greater among anthropometric and biomechanical variables as compared to psychological variables. These data suggest that BP strength among a heterogeneous, resistance-trained population is explained by multiple factors and is more strongly associated with physical than psychological variables. [ABSTRACT FROM AUTHOR]

Low back pain (LBP) is a leading cause of disability. The use of deadlift-based assessments in assessing LBP is becoming common in clinical settings, but these concepts have not been well studied. We sought to compare force and muscle excitation during isometric deadlifts in participants suffering from LBP versus asymptomatic controls. We also compared these outcomes for conventional versus hexagonal barbells. Sixteen adults with mild-to-moderate, acute, non-specific LBP and 19 controls performed maximal, isometric deadlifts while standing on a force plate using conventional and hexagonal barbells. Surface electromyographic signals were recorded from the upper trapezius, external oblique, erector spinae, vastus lateralis, and biceps femoris. Normalized peak force and peak rate of force development were similar for those with acute, non-specific LBP and controls. Surface electromyographic excitation was not different between groups, but was higher with the hexagonal barbell for the vastus lateralis and upper trapezius. Both groups felt equally safe and confident. In summary, the presence of acute, non-specific LBP did not impair peak and rapid force or muscle excitation. Hexagonal barbells may optimize knee extensor and trapezius activation. Deadlift-based force assessments appear safe and may be useful in the assessment of functional strength in patients with acute, non-specific LBP. [ABSTRACT FROM AUTHOR]

Featured Application: This manuscript performs an electromyographic analysis of two exercises for conditioning the upper muscle extremities. Thus, a greater knowledge for prescribing these exercises in strengthening or functional recovery programs will be obtained. Pullover and straight arm pulldown exercises are commonly used in resistance exercise programs to improve sports performance or in physical activity health programs. This study aimed to evaluate the individual electromyographic (EMG) activity of the pectoralis major (clavicular, sternal, and costal portions), latissimus dorsi, anterior deltoid, triceps brachii, and rectus abdominis muscles in a barbell pullover exercise at a 100% biacromial width and a straight arm pulldown exercise at a 100% and 150% biacromial width and to compare the EMG activity in these selected muscles and exercises. Twenty healthy and physically active adults performed a set of eight repetitions of each exercise against 30% of their body mass. The barbell pullover exercise presented a higher EMG activity (p ≤ 0.01) than the straight arm pulldown exercise in both biacromial widths in all evaluated muscles except for the latissimus dorsi and the triceps brachii. These muscles showed the highest EMG activity in the straight arm pulldown exercise at both biacromial widths. In all of the exercises and muscles evaluated, the concentric phase showed a greater EMG activity than the eccentric phase. In conclusion, the barbell pullover exercise can highlight muscle activity in the pectoralis major (mainly in the sternal and lower portions), triceps brachii, and rectus abdominis muscles. However, the straight arm pulldown exercise at 100% and 150% biacromial widths could be a better exercise to stimulate the latissimus dorsi and triceps brachii muscles. Moreover, all exercises showed significantly greater EMG activity (p < 0.001) in the concentric phase than in the eccentric phase for all the evaluated muscles. [ABSTRACT FROM AUTHOR]

Background: Various studies have used different exercise protocols as post-activation performance enhancement (PAPE) stimulus; however, little attention has been given to the effects of exercise range of motion on the PAPE effect and subsequent performance enhancement. This study aimed to compare the PAPE responses induced by the bench press performed with different ranges of motion on subsequent bench press throw performance. Methods: Ten resistance-trained males (age: 26 ± 3 years; body mass: 93.2 ± 9.4 kg; height: 181 ± 6 cm; experience in resistance training: 6.3 ± 2.4 years; relative bench press one-repetition maximum (1RM) 1.54 ± 0.2 kg/body mass) performed four experimental sessions consisting of a single set of the bench press at 80%1RM until mean barbell velocity dropped by 10% as the conditioning activity (CA) with a (1) standard, (2) cambered, (3) and reversed cambered barbell or a control condition in which the participants did not perform any CA. To assess the PAPE effect, single-sets of 2 repetitions of the bench press throw at 30%1RM were performed before and after the CA at the following time points: 2, 4, 6, 8, 10 min. Results: The two-way ANOVA (4 conditions × 2time points) showed a significant interaction for peak power (p < 0.001; η2 = 0.556) and peak velocity (p = 0.001; η2 = 0.457). The standard barbell bench press CA led to the greatest performance enhancement in peak power (p = 0.001; ES = 0.54) and in peak velocity (p = 0.002; ES = 0.71) within the examined conditions. Conclusions: The results of this study indicate that the range of motion of the CA has a significant impact on the magnitude of the PAPE response, and the greatest effect can be reached when the range of motion of the CA and the subsequent explosive task is similar. [ABSTRACT FROM AUTHOR]

This study aimed to determine whether the intra-complex active recovery within the strengthpower potentiating complex will impact the upper-body post-activation performance enhancement effect and how the magnitude of this effect will change across the upperbody complex training session. Thirteen resistance-trained males [the age, bodymass, height, experience in resistance training, and one-repetition maximum (1RM) in bench press were 27 ± 4 years; 92.3 ± 15.4 kg; 182 ± 6 cm; 6.4 ± 2.4 years, and 118 ± 29 kg, respectively) participated in this study. Each participant completed a baseline bench press throw performance assessment at 30% 1RM. Next, five strength-power potentiating complexes consisting of a bench press at 80% 1RM were tested until the average barbell velocity decreased by 10% as a conditioning activity, and 6min later, a re-test of bench press throw was carried out. During one experimental session during the rest interval inside the complex, they performed swiss ball leg curls, while between the complexes, a plank exercise (PAP-A) was performed. During the second experimental session, participants performed no exercises within the strength-power potentiating complexes and between them (PAP). Under control conditions, participants ran the same protocol (as the PAP condition) without the conditioning activity (CTRL). Friedman's test showed significant differences in peak (test = 90.634; p < 0.0001; Kendall's W = 0.410) and average (test = 74.172; p < 0.0001; Kendall's W = 0.336) barbell velocities during bench press throw. Pairwise comparisons indicated that the peak and average barbell velocities significantly increased in the fourth set [p = 0.022, effect size (ES) = 0.76 and p = 0.013, ES = 0.69, respectively], and the average barbell velocity was also increased in the second set (p = 0.018, ES = 0.77) in comparison to the baseline value during the PAP-A condition. Moreover, the peak barbell velocity was increased in the second (p = 0.008, ES = 0.72) and third (p = 0.019, ES = 0.76) sets compared to the baseline value during the PAP condition. This study showed that body-weight lower-body exercise as an intracomplex active recovery did not impair the upper-body post-activation performance enhancement effect across the complex training session. [ABSTRACT FROM AUTHOR]

Objective: The lunge squat is one of the exercises to strengthen the lower limbs, however, there is little evidence of the effects of different equipment. The purpose of this study was to investigate the biomechanical effects of different types of equipment and loads on the lunge squat's effect on the lower limbs. Methods: Fourteen male fitness novices participated in the experiment. Kinematics and kinetics in the sagittal plane using dumbbells, barbells, and weighted vests were measured using OpenSim. Two-way repeated measures ANOVA and one-dimensional statistical parametric mapping were used in the statistical analysis (SPM1D). Results: Range of motion (ROM) change in the knee joint was more obvious when using a barbell, whereas ROM when using a dumbbell was minimal. Compared to other joints, the joint moment at the hip joint was the largest and changed more significantly with increasing weight-bearing intensity, and the change was more pronounced with the dumbbell. For the center of pressure (COP) overall displacement, the dumbbell produced a smaller range of displacement. Conclusions: Dumbbells are suggested for male beginners to improve stability, barbells for the more experienced, and a low-weighted vest may be more appropriate for those with knee pain. [ABSTRACT FROM AUTHOR]

The flanged, barbell, and rectangular squat reinforced concrete (RC) walls are broadly used in low-rise commercial and highway under and overpasses. The shear strength of squat walls is the major design consideration because of their smaller aspect ratio. Most of the current design codes or available published literature provide separate sets of shear capacity equations for flanged, barbell, and rectangular walls. Also, a substantial scatter exists in the predicted shear capacity due to a large discrepancy in the test data. Thus, this study aims to develop a single gene expression programming (GEP) expression that can be used for predicting the shear strength of these three cross-sectional shapes based on a dataset of 646 experiments. A total of thirteen influencing parameters are identified to contrive this efficient empirical compared to several shear capacity equations. Owing to the larger database, the proposed model shows better performance based on the database analysis results and compared with 9 available empirical models. [ABSTRACT FROM AUTHOR]

An electric solar wind sail (electric sail or E-sail) is a new type of propulsion system that does not require propellant. This paper proposes a nonlinear model predictive control law based on deep learning to control the attitude of a barbell electric sail. A barbell E-sail is composed of two tip satellites connected via long conductive tethers to a central insulated confluence point. The two tethers are insulated from each other at the confluence point such that the voltages of the two tethers can be independently controlled. The attitude dynamics of the system is modelled using a nonsingular description of tether orientation. To reduce online computation loads, the proposed control scheme has a two-stage design, namely, an offline stage and an online stage. In the offline stage, a large amount of data is generated using the nonlinear model predictive control law and then taken as a dataset to train a deep neural network. In the online stage, feedback control of the system attitude is achieved with extremely low computational cost by performing real-time mapping from the system state to the control output using the trained deep neural network. Finally, the efficacy and performance of the proposed deep learning-based control law are demonstrated via numerical case studies. • Attitude dynamics of an E-sail system is modelled by a nonsingular formulation. • Nonlinear dynamics and inherent constraints of the system are accounted for. • Extremely low computational cost of feedback control is achieved using a DNN. [ABSTRACT FROM AUTHOR]

A novel transverse-mode overlapping technology is proposed to enable significant advancement in the development of wideband extended interaction klystrons (EIKs). To obtain the individual beams with comparatively low perveance and low current density, the double sheet beams are used to drive the circuit. For the purpose of allowing the circuit to operate in the fundamental mode, two innovative extended structures, ridge-loaded barbell structure (RLBS) and ridge-loaded ladder structure (RLLS), are proposed. It is found that both the two structures are capable of transverse-mode overlapping (superposition of TM11 mode and TM21 mode) by adjusting the dimensions of the ridges. On the basis of such ideas, a wideband six-cavity circuit at 0.22 THz is designed. The input and output cavities are with the RLBS, while the idler cavities are with the RLLS. The bandwidth of the output cavity and the frequency tuning of cavities are carefully considered to preserve good gain uniformity across the continuous frequency band. The particle-in-cell (PIC) simulation results show that the maximum output power reaches 138 W with the operating voltage of 15.8 kV and each beam current of 0.3 A, and the corresponding gain is 34.3 dB. The 1-dB bandwidth is 1.95 GHz, approximately 1% of the operating frequency. The relatively small in-band ripple indicates the excellent bandwidth characteristics of the circuit. [ABSTRACT FROM AUTHOR]

The aim of the study was to investigate the acute effects of attaching chains on barbell kinematics and muscle activation in the bench press. Twelve resistance-trained men (height: 1.79 ± 0.05 m, weight: 84.3 ± 13.5 kg, one repetition maximum (1-RM) bench press of 105 ± 17.1 kg) lifted three repetitions of bench press in three conditions: (1) conventional bench press at 85% of 1-RM and bench press with chains that were (2) top-matched and (3) bottom-matched with the resistance from the conventional resistance lift. Barbell kinematics and the muscle activity of eight muscles were measured at different heights during lowering and lifting in the three conditions of the bench press. The main findings were that barbell kinematics were altered using the chains, especially the 85% bottom-matched condition that resulted in lower peak velocities and longer lifting times compared with the conventional 85% condition (p ≤ 0.043). However, muscle activity was mainly only affected during the lowering phase. Based upon the findings, it was concluded that using chains during the bench press alters barbell kinematics, especially when the resistance is matched in the bottom position. Furthermore, muscle activation was only altered during the lowering phase when adding chains to the barbell. [ABSTRACT FROM AUTHOR]

We determined the marker-less barbell auto-tracking accuracy using the Kanade–Lucas–Tomasi (KLT) algorithm in a digital video for two-dimensional analysis (2D-AT). The position coordinates of the barbell's right end during multiple loads (60%–90% of one-repetition maximum) of snatch motion in eight participants were recorded using a three-dimensional motion capture system. Simultaneously, the snatch motion was recorded by a digital camera from the right side. Based on the digital video, the center of the barbell's right end was auto-tracked using the KLT algorithm. Six barbell kinematic variables (forward, backward, and vertical displacement, peak forward, backward, and vertical velocity) were calculated. Intraclass correlation coefficient (ICC) analysis was performed to establish the agreement level between the methods. The Bland–Altman plots and regression were used to examine the agreement between the methods. ICCs of 0.999–0.971 revealed a strong agreement level between the methods. The Bland–Altman plot showed small bias (-0.001–0.001 m, -0.034 –-0.005 m/s). We considered that 2D-AT could obtain barbell position coordinates with sufficient accuracy to discriminate the difference in the lifter's level and a successful or unsuccessful lift. [ABSTRACT FROM AUTHOR]

In this paper, we design a PD-fuzzy controller which is developed from PID method. The model for testing here is acrobot - a SIMO model which imitates the action of barbell athlete. We create a hardware platform for real experiment. The aim of controlling is keeping link 1 at up-position and link 2 at down-position. Through both simulation and experiment, the PD-fuzzy controller shows better control quality than original PID controller. [ABSTRACT FROM AUTHOR]