904 results on '"BARBELLS"'
Search Results
2. The hide-and-seek effect of pulsed-flows in a potamodromous cyprinid fish.
- Author
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Leite, Renan, Costa, Maria João, Mameri, Daniel, Afonso, Fernando, Pinheiro, António, Santos, José Maria, and Boavida, Isabel
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GLUCOSE analysis , *HABITAT selection , *FISH habitats , *WATER power , *BARBELLS - Abstract
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]
- Published
- 2024
- Full Text
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3. Use of autologous micrografts associated with xenogeneic anorganic bone in vertical bone augmentation procedures with Barbell Technique®.
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Cosmo, Luiz Antonio Mazzucchelli, Coutinho, Reginaldo Machado, Macedo, Luís Guilherme Scavone, Aloise, Antonio Carlos, Jayme, Sérgio Jorge, Zeferino, João Pedro Grandini, Graziano, Antonio, Martinez, Elizabeth Ferreira, Moy, Peter Karyen, and Pelegrine, André Antonio
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GUIDED bone regeneration , *CONE beam computed tomography , *SINUS augmentation , *BONE growth , *PERIOSTEUM , *BARBELLS , *BONE grafting - Abstract
Introduction Purpose Materials and methods Results Conclusion Bidirectional vertical ridge augmentation in the posterior maxilla is very challenging.To evaluate the regenerative potential of micrografts, derived from periosteum or bone tissue, added to an anorganic xenograft in vertical reconstruction of the posterior maxilla, by a prospective, controlled study.After clinical selection and the analysis of CBCT scans, 24 posterior maxillary sites, in 19 patients, were treated by using Barbell Technique®. Sites requiring both inlay and onlay reconstruction were enrolled in the study. In the Control Group (CG, n = 8), a xenograft was used in the inlay site and for the onlay site, a 1:1 mix of xenograft and an autograft was used. In Test Group 1 (TG1, n = 8), both inlay and onlay sites were grafted with the xenograft associated with the micrografts derived from periosteum. In Test Group 2 (TG2, n = 8), both inlay and onlay sites were grafted with the xenograft associated with the micrografts derived from bone. Six months after the procedures, CBCT scans were obtained, and bone biopsy samples were harvested during implant placement surgery. The bone specimens were analyzed histomorphometrically, by measuring the percentages of vital mineralized tissue (VMT), non vital mineralized tissue (NVMT) and non mineralized tissue (NMT). Immunohistochemically, the levels of VEGF were categorized by a score approach.Histomorphometric analysis revealed, for the inlay grafts, no significant difference among the groups for VMT, NVMT and NMT. However, for onlay grafts, CG achieved a higher amount of VMT in comparison with TG2, and the opposite occurred for NMT values. In this regard, no statistical difference was observed between CG and TG1. Concerning immunohistochemistry, the VEGF values for CG and TG1 were slightly higher than those obtained by TG2 for both inlay and onlay grafts, but without statistical significance. CBCT analysis showed a similar level of gain for all groups, for both inlay and onlay bone augmentation sites. Clinically, one implant (in CG) within a total of 50 implants installed, had early failure and was replaced after 3 months. All patients received implant supported prosthesis.This study indicated that the clinical use of micrograft derived from periosteum may have some potential to increase bone formation in onlay reconstructions, unlike the micrograft derived from bone tissue. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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4. The Impact of Exercise Order on Velocity Performance in the Bench Press and the Squat: A Comparative Study.
- Author
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Pereira, Rogério Martins, Marques, Diogo Luís, Alves, Ana Ruivo, Marinho, Daniel Almeida, Neves, Pedro Pombo, Silva, António José, and Neiva, Henrique Pereira
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LINEAR velocity ,BLOOD lactate ,HEART beat ,BENCH press ,VELOCITY ,BARBELLS - Abstract
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]- Published
- 2024
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5. 4 MOVES PERFECT FOR A Barbell Workout.
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Nair, Praveen and Nair, Maheek
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BARBELLS ,WEIGHT lifting equipment ,MUSCLE growth ,PHYSICAL fitness ,WOMEN'S mental health - Abstract
The article discusses the effectiveness of barbell workouts in enhancing muscle growth, bone strength, and overall physical and mental health for women. Topics discussed include specific barbell exercises, their targeted muscle groups, and the broader benefits of incorporating barbell training into a fitness routine.
- Published
- 2024
6. Further results on random walk labelings.
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Fried, Sela and Mansour, Toufik
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RANDOM walks , *GRAPH labelings , *RANDOM numbers , *RANDOM graphs , *BARBELLS , *LOLLIPOPS , *TADPOLES - Abstract
In a previous work, we defined and studied random walk labelings of graphs. These are graph labelings that are obtainable by performing a random walk on the graph, such that each vertex is labeled upon its first visit. In this work, we calculate the number of random walk labelings of several natural graph families: The wheel, fan, barbell, lollipop, tadpole, friendship, and snake graphs. Additionally, we prove several combinatorial identities that emerged during the calculations. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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7. Validity and Reliability of a Commercially Available Inertial Sensor for Measuring Barbell Mechanics during Weightlifting.
- Author
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Chavda, Shyam, Sandau, Ingo, Bishop, Chris, Xu, Jiaqing, Turner, Anthony N., and Lake, Jason P.
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MOTION capture (Human mechanics) ,WEIGHT lifting ,UNITS of measurement ,WEIGHT lifters ,KINEMATICS ,BARBELLS - Abstract
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]
- Published
- 2024
- Full Text
- View/download PDF
8. Sex differences in intra-set kinematics and electromyography during different maximum repetition sets in the barbell back squat?
- Author
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van den Tillaar, Roland, Bao Fredriksen, Andrea, Hegdahl Gundersen, Andreas, and Nygaard Falch, Hallvard
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RESISTANCE training , *OLDER men , *KINEMATICS , *VELOCITY , *BARBELLS - Abstract
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]
- Published
- 2024
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9. Dynamic analysis and optimization of snatch lift based on barbell trajectory and on an anthropometric model comprised of six links.
- Author
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Jon, Min Hyok and Rim, Un‐Ryong
- Subjects
CENTER of mass ,DEGREES of freedom ,ACCELERATION (Mechanics) ,WEIGHT lifting ,BARBELLS - Abstract
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]
- Published
- 2024
- Full Text
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10. The mean–variance (in)efficiency of duration‐based immunization.
- Author
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François, Pascal and Moraux, Franck
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IMMUNIZATION ,CONVEX sets ,YIELD curve (Finance) ,BARBELLS ,BONDS (Finance) ,REINVESTMENT ,EFFICIENT market theory - Abstract
Empirical studies report inconclusive assessment of duration‐based immunization, notably showing that more sophisticated strategies do not outperform immunization relying on Macaulay duration. This article provides a mean–variance framework to explain this puzzle. We characterize the efficient portfolio allocations for a stylized barbell strategy trading off reinvestment risk with discounting risk. We show, in a model‐free setting, that barbell allocations form a convex set in the mean–variance space, and the endpoints of the efficient frontier can switch as time passes, reversing the set of efficient allocations. Consequently, duration‐based immunization, which is not minimum variance, can exhibit temporary inefficiency. This result is numerically illustrated in a one‐factor Gaussian and a two‐factor non‐Gaussian model. Using yield curve scenarios resampled from U.S. data over the 1977–2020 period, we further corroborate our conclusions non‐parametrically, and find that duration‐based immunization is sometimes inefficient. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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11. The Strong Spectral Property of Graphs: Graph Operations and Barbell Partitions.
- Author
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Allred, Sarah, Curl, Emelie, Fallat, Shaun, Nasserasr, Shahla, Schuerger, Houston, Villagrán, Ralihe R., and Vishwakarma, Prateek K.
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BARBELLS , *SYMMETRIC matrices , *INVERSE problems - Abstract
The utility of a matrix satisfying the Strong Spectral Property has been well established particularly in connection with the inverse eigenvalue problem for graphs. More recently the class of graphs in which all associated symmetric matrices possess the Strong Spectral Property (denoted G SSP ) were studied, and along these lines we aim to study properties of graphs that exhibit a so-called barbell partition. Such a partition is a known impediment to membership in the class G SSP . In particular we consider the existence of barbell partitions under various standard and useful graph operations. We do so by considering both the preservation of an already present barbell partition after performing said graph operations as well as barbell partitions which are introduced under certain graph operations. The specific graph operations we consider are the addition and removal of vertices and edges, the duplication of vertices, as well as the Cartesian products, tensor products, strong products, corona products, joins, and vertex sums of two graphs. We also identify a correspondence between barbell partitions and graph substructures called forts, using this correspondence to further connect the study of zero forcing and the Strong Spectral Property. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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12. Row-factorization matrices in Arf numerical semigroups and defining ideals.
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Süer, Meral and Yeşil, Mehmet
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BARBELLS - Abstract
In this paper, we investigate the row-factorization matrices of Arf numerical semigroups, and we provide the full list of such matrices of certain Arf numerical semigroups. We use the information of row-factorization matrices to detect the generic nature and to find generators of the defining ideals. [ABSTRACT FROM AUTHOR]
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- 2024
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13. Eigensharp Property of Some Certain Graphs and their Complements.
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Rawshdeh, Eman, Abdelkarim, Heba Adel, and Rawashdeh, Edris
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BIPARTITE graphs , *BARBELLS , *SUBGRAPHS , *COMPLETE graphs , *EIGENVALUES , *FRIENDSHIP - Abstract
The biclique partition number of a graph G, denoted by bp(G), is the minimum number of complete bipartite subgraphs are needed to be representing all edges of G. A graph G is called an eigensharp graph if it is satisfying bp(G) = max{i-(A(G)), i+(A(G))} where i-(A(G)) and i+(A(G)) are the number of negative and positive eigenvalues of the adjacency matrix of G, respectively. In this paper, we are interested in studying some special graphs in terms of having the property of eigensharp. We show that the barbell graph, the sun graph, the friendship graph and their complements have the property of eigensharp. [ABSTRACT FROM AUTHOR]
- Published
- 2024
14. High resolution magnetic field imaging probe with two rows of TMR sensors for small defects inspection.
- Author
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Long, Cai, Wang, Yuanyuan, Dong, Haoran, Tao, Yu, and Ye, Chaofeng
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MAGNETIC fields , *TUNNEL magnetoresistance , *SEALING (Technology) , *PIXELS , *DETECTORS , *EDDY current testing , *FEATURE extraction , *BARBELLS - Abstract
It is still a challenging problem to detect small defects for eddy current array probes, which requires the probes to possess excellent sensitivity, as well as high spatial resolution. This paper presents a novel high-resolution magnetic field imaging probe with two rows of tunneling magnetoresistance (TMR) array sensors. The bare die sensors are integrated on a printed circuit board by golden wire bonding technology. The two rows of sensors are placed staggered with each other. The data of the two arrays are merged into a matrix, in which way the image pixel pitch is increased to 0.25 mm. The probe employs a differential scheme to suppress the noise, so as to detect the weak signal of small defects. To highlight the weak defect indications, feature extraction and segmentation algorithms are developed. The experimental results confirm that the proposed method can inspect a small defect with dimensions 1 mm (length) × 0.1 mm (width) × 0.1 mm (depth) on a stainless-steel sample. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
15. Reinforcement learning-based attitude control for a barbell electric sail.
- Author
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Ma, Xiaolei and Wen, Hao
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BARBELLS ,REINFORCEMENT learning ,SOLAR sails ,ARTIFICIAL satellite attitude control systems ,ELECTRIC propulsion ,ELECTRIC windings ,SOLAR wind ,COMPUTATIONAL neuroscience - Abstract
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]
- Published
- 2024
- Full Text
- View/download PDF
16. The stability of the deadlift three repetition maximum.
- Author
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Guppy, Stuart N, Nagatani, Tsuyoshi, Poon, Wayne C K, Kendall, Kristina L, Lake, Jason P, and Haff, G Gregory
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BENCH press ,EFFECT sizes (Statistics) ,RESISTANCE training ,BARBELLS ,VERTICAL jump - Abstract
This study investigated the stability of three repetition maximum (3RM) strength during the deadlift. Eleven participants performed four testing sessions comprising a one repetition maximum test and 3RM tests separated by 48 h. Preparedness was assessed before each testing session using countermovement jumps and by measuring barbell velocity during each set of deadlifts. Trivial statistically significant differences were determined for the 3RM between T1 and both T2 (p = 0.012; ES [95% CI] = −0.1 [−0.58, 0.41]) and T3 (p = 0.027; ES [95% CI] = −0.09 [−0.57, −0.43]). No significant differences were noted between T2 and T3 (p = 0.595; ES [95% CI] = 0.01 [−0.49, 0.50]). No significant differences in jump height (p = 0.071), time-to-take-off (p = 0.862), eccentric displacement (p = 0.209), or mean force during any countermovement jump sub-phase were found between each session (p = 0.529–0.913). Small differences in barbell mean velocity were found between both T1–T2 (effect size statistics (ES) = −0.21–0.27) and T2–T3 (ES = 0.31–0.48), while trivial differences were found at others. Therefore, 3RM deadlift strength appears stable enough over a microcycle to continue using traditionally recommended heavy/light programming strategies. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
17. Changes in deadlift six repetition maximum, countermovement jump performance, barbell velocity, and perceived exertion over the duration of a microcycle.
- Author
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Guppy, Stuart N., Nagatani, Tsuyoshi, Poon, Wayne C. K., Kendall, Kristina L., Lake, Jason P., and Gregory Haff, G.
- Subjects
BENCH press ,BARBELLS ,RATE of perceived exertion ,VERTICAL jump ,VELOCITY - Abstract
The primary aim of this study was to investigate the stability of the six-repetition maximum (6RM) deadlift over the length of a five-day microcycle and whether the fatigue induced by maximal effort testing detrimentally impacted preparedness. Twelve participants performed four testing sessions, comprising a one-repetition maximum test and three 6RM tests separated by 48 hours. Countermovement jumps were performed before each testing session, and barbell velocity was measured during each warm-up set to assess changes in preparedness. The 6RM deadlift was not statistically different between any of the testing sessions (p =.056; η
p 2 = 0.251). Similarly, there were no significant differences in jump height or other CMJ variables between sessions (p >.05). There were small to moderate differences in mean barbell velocity between the first and second 6RM test (g = 0.24–0.88), while there were only small differences in mean velocity (MV) between the second and third 6RM test at some of the warm-up loads (40% 6RM: g = 0.20; 80% 6RM: g = −0.47). Taken collectively, these data indicate that 6RM deadlift strength is stable over five days and does not appear to induce sufficient fatigue to impact vertical jump performance or rating of perceived exertion despite some changes in barbell velocity. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
18. Braking and Propulsion Phase Characteristics of Traditional and Accentuated Eccentric Loaded Back Squats.
- Author
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Suchomel, Timothy J., Cantwell, Conor J., Campbell, Brookelyn A., Schroeder, Zachary S., Marshall, Lauren K., and Taber, Christopher B.
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SQUAT (Weight lifting) ,BARBELLS ,BRAKE systems - Abstract
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]
- Published
- 2024
- Full Text
- View/download PDF
19. Are Diminishing Potentiation and Large Extensor Moments the Cause for the Occurrence of the Sticking Region in Maximum Free-Weight Barbell Back Squats among Resistance-Trained Males?
- Author
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van den Tillaar, Roland, Falch, Hallvard Nygaard, and Larsen, Stian
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HAMSTRING muscle ,VASTUS lateralis ,STATURE ,MALES ,BARBELLS ,KNEE ,CALF muscles - Abstract
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, η
p ² ≥ 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]- Published
- 2024
- Full Text
- View/download PDF
20. Fatigue and Metabolic Responses during Repeated Sets of Bench Press Exercise to Exhaustion at Different Ranges of Motion.
- Author
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Tsoukos, Athanasios, Krzysztofik, Michał, Wilk, Michal, Zajac, Adam, Panagiotopoulos, Michail G., Psarras, Ilias-Iason, Petraki, Despina P., Terzis, Gerasimos, and Bogdanis, Gregory C.
- Subjects
RANGE of motion of joints ,BENCH press ,BLOOD lactate ,BARBELLS ,MUSCLE fatigue ,LIFTING & carrying (Human mechanics) - Abstract
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]
- Published
- 2024
- Full Text
- View/download PDF
21. Applicability evaluation of plunger lift technology in shale gas wells.
- Author
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Yu Fan, Jianhua Xiang, Bochun Li, Jiaxiao Chen, Mi Jiang, Fan Yu, Zongxiao Ren, and Leilei Zhang
- Subjects
GAS wells ,OIL shales ,HORIZONTAL wells ,LIQUEFIED gases ,SHALE gas ,NATURAL gas ,BARBELLS ,EVALUATION methodology - Abstract
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]
- Published
- 2024
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22. A Novel Barbell‐Shaped Perforated Auxetic Metastructure with Superior Auxetic Effect.
- Author
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Zhang, Qi, Zhu, Yilin, Wang, Yihe, and Li, Jian
- Subjects
- *
POISSON'S ratio , *BARBELLS , *STRESS concentration , *DESIGN exhibitions , *ORTHOGONAL arrays - Abstract
Recently, artificial perforated auxetic metastructures with negative Poisson's ratio have attracted considerable attention with the superior mechanical properties. The concepts and design methods of various types of perforated auxetic metastructures have developed rapidly. However, the effective Poisson's ratio exhibited by the majority of current perforated auxetic metastructures has a lower limit of −1, which restrains their potential applications significantly. Herein, a novel 2D perforated auxetic metastructure is proposed by arraying orthogonal barbell‐shaped holes onto a sheet structure. The mechanical properties and the underlying deformation mechanism of the proposed auxetic metastructure are then investigated by performing experimental tests and finite element simulations. Results show that the lower limit of the Poisson's ratio exhibited by the proposed auxetic metastructure surpasses −1 remarkably and the proposed design hence exhibits much better auxetic performance compared with existing designs. It is also revealed that the proposed design exhibits relatively low local stress distribution. The results of this study will broaden the potential applications of perforated auxetic metastructures in many engineering fields. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
23. RELATIONSHIP BETWEEN STANCE WIDTH VARIATION DURING ONE REPETITION MAXIMUM BARBELL HIP THRUST PERFORMANCE AND KICKING SPEED FOR YOUNG ELITE SILAT ATHLETES.
- Author
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Nasir, Muhammad Zulqarnain Mohd, Nadzalan, Ali Md, Azmi, Abdul Muiz Nor, and Adnan, Mohd Aizzat
- Subjects
BARBELLS ,ELITE athletes ,PEARSON correlation (Statistics) ,KICKING (Football) ,KEY performance indicators (Management) - Abstract
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]
- Published
- 2023
- Full Text
- View/download PDF
24. TRANSFORMING KEMPO FITNESS: ENHANCING PHYSIOLOGICAL RESPONSES AND PHYSICAL PERFORMANCE IN ADOLESCENTS VIA A TABATA-BASED METHOD.
- Author
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Nurkholis, Sifaq, Aghus, Suyoko, Andri, Nirwansyah, Waristra Tyo, Pramono, Bayu Agung, and Arisanti, Raden Roro Shinta
- Subjects
BARBELLS ,ELITE athletes ,PEARSON correlation (Statistics) ,KICKING (Football) ,KEY performance indicators (Management) - Abstract
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]
- Published
- 2023
- Full Text
- View/download PDF
25. Barbell Technique for Three-Dimensional Bone Augmentation.
- Author
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Nunes, Marcelo Pereira, de Macedo, Luís Guilherme Scavone, Santamaria, Mauro Pedrine, Ribeiro, João Carlos, Moy, Peter Karyen, and Pelegrine, André Antonio
- Subjects
BARBELLS ,ALVEOLAR process ,BONE growth ,DENTAL implants ,OPERATIVE surgery ,BONE grafting - Abstract
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]
- Published
- 2023
- Full Text
- View/download PDF
26. Effects of Squat Combined Barbell with Elastic Band on Muscle Strength, Body Composition, and Balance in Working Age Men.
- Author
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Fungnumcharoensab, Kritsada and Anek, Achariya
- Subjects
BODY composition ,OLDER men ,RESISTANCE training ,BARBELLS ,SQUAT (Weight lifting) ,MUSCLE strength ,MALE employees ,RESISTANCE bands (Exercise equipment) - Abstract
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]
- Published
- 2023
27. Barbell Technique: A Novel Approach for Bidirectional Bone Augmentation: Clinical and Tomographic Study.
- Author
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Macedo, Luís Guilherme Scavone de, Pelegrine, André Antonio, and Moy, Peter Karyen
- Subjects
BONE grafting ,BARBELLS ,CANCELLOUS bone ,COMPUTED tomography ,DENTAL implants ,GUIDED tissue regeneration - Abstract
Horizontal bone augmentation is a common surgical procedure used in implant therapy to achieve adequate bone volume to permit dental implant placement. However, most current techniques are focused on unidirectional bone reconstruction (grafting only on the buccal side). This study was carried out to validate a new device that will permit bidirectional bone augmentation. Ten patients of both sexes (7 women and 3 men), with ages ranging from 29 to 62 years, who needed a bidirectional horizontal bone augmentation in maxilla were separated in accordance with the horizontal alveolar change (HAC) classification published by Pelegrine et al (2018). The patients classified as HAC 3 (ie, containing remaining cancellous bone at the recipient bed) received the Barbell device with xenogeneic biomaterial and a collagen membrane, whereas HAC 4 patients (ie, with no remaining cancellous bone at the recipient bed) received the Barbell device with a mixture of autogenous bone chips and xenogeneic biomaterial covered by a collagen membrane. For each patient, two computerized tomography scans were performed (T0 at baseline and T1 at 6 months postoperative examinations). Mean bone thickness (T0) in the studied sites were 3.25 ± 0.35 in HAC 3 and 1.98 ± 0.5 in HAC 4 patients. The mean bone thickness achieved after 6 months was 7.70 ± 0.89 mm and 8.62 ± 0.89 in HAC 3 and 4, respectively. All grafted sites were able to receive dental implants in adequate prosthetic positions. Based on these results, the use of this novel device permits bidirectional horizontal bone augmentation. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
28. Human Activity Recognition Based on Continuous-Wave Radar and Bidirectional Gate Recurrent Unit.
- Author
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Zhou, Junhao, Sun, Chao, Jang, Kyongseok, Yang, Shangyi, and Kim, Youngok
- Subjects
HUMAN activity recognition ,RADAR signal processing ,RADAR ,CONTINUOUS wave radar ,SMART homes ,BARBELLS ,SECURITY systems ,MOTION capture (Human mechanics) - Abstract
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]
- Published
- 2023
- Full Text
- View/download PDF
29. Intra-Rater and Test–Retest Reliability of Barbell Force, Velocity, and Power during the Landmine Punch Throw Test Assessed by the GymAware Linear Transducer System.
- Author
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Oleksy, Łukasz, Kuchciak, Maciej, Bril, Grzegorz, Mika, Anna, Przydział, Marta, Pazdan-Śliż, Iwona, Kielnar, Renata, Racheniuk, Henryk, Adamska, Olga, and Deszczyński, Michał
- Subjects
STATISTICAL reliability ,BARBELLS ,LINEAR systems ,LAND mines ,TRANSDUCERS ,VELOCITY ,LENGTH measurement - Abstract
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]
- Published
- 2023
- Full Text
- View/download PDF
30. Examining Captive and Inverse Captive Domination in Selected Graphs and Their Complements.
- Author
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Alrikabi, Zainab Yasir and Omran, Ahmed A.
- Subjects
DOMINATING set ,BARBELLS ,LOLLIPOPS - Abstract
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]- Published
- 2023
- Full Text
- View/download PDF
31. Optimal secret share distribution in degree splitting communication networks.
- Author
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Falcón, Raúl M., Aparna, Venkitachalam, and Mohanapriya, Nagaraj
- Subjects
TELECOMMUNICATION systems ,CLOUD storage ,GRAPH labelings ,REGULAR graphs ,MULTICASTING (Computer networks) ,BARBELLS ,DATA transmission systems - Abstract
Dynamic coloring has recently emerged as a valuable tool to optimize cryptographic protocols based on secret sharing, which enforce data security in communication networks and have significant importance in both online storage and cloud computing. This type of graph labeling enables the dealer to distribute secret shares among the nodes of a communication network so that everybody can recover the secret after a minimum number of rounds of communication. This paper delves into this topic by dealing with the dynamic coloring problem for degree splitting graphs. The topological structure of the latter enables the dealer to avoid dishonesty by adding control nodes that supervise all those participants with a similar influence in the network. More precisely, we solve the dynamic coloring problem for degree splitting graphs of any regular graph. The irregular case is partially solved by establishing a lower bound for the corresponding dynamic chromatic number. As illustrative examples, we solve the dynamic coloring problem for the degree splitting graphs of cycles, cocktail, book, comb, fan, jellyfish, windmill and barbell graphs. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
32. Extended range of motion does not induce greater muscle damage than conventional range of motion in the bench press exercise.
- Author
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MATYKIEWICZ, Patryk, KRZYSZTOFIK, Michał, and ZAJĄC, Adam
- Subjects
BENCH press ,RANGE of motion of joints ,RESISTANCE training ,CREATINE kinase ,BARBELLS - Abstract
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]
- Published
- 2023
- Full Text
- View/download PDF
33. Effect of different set configurations on barbell trajectories during the power snatch.
- Author
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Nagatani, Tsuyoshi, Haff, G Gregory, Guppy, Stuart N, Poon, Wayne, and Kendall, Kristina L
- Subjects
BARBELLS ,REPEATED measures design ,RESISTANCE training ,POWER series ,MOTION capture (Human mechanics) ,WEIGHT lifting - Abstract
This study aimed to investigate the effect of different set configurations on barbell trajectories during a series of power snatch sets. Ten strength-power athletes (height: 1.78 ± 0.09 m, body mass: 88.7 ± 14.3 kg, age: 28.9 ± 4.8 years) with at least 6 months of training experience performing the power snatch participated in this study. Each participant completed three experimental protocols as part of a randomized repeated measures design. The three protocols tested were a traditional, cluster, and ascending cluster set protocol where training loads were increased across the repetitions contained within each set. All protocols required each participant to perform the power snatch with three sets of five repetitions at an average load of 75% of one-repetition maximum. Three-dimensional barbell trajectories were recorded using a motion capture system during each set protocol. Participants maintained barbell trajectories within each set of both traditional and cluster protocols. This result indicates that higher intensities (>75% of one-repetition maximum) than those used in this study should be used when using cluster sets that are designed to maximize the benefits of cluster sets for maintaining barbell trajectories during a series of power snatch sets performed for five repetitions. Additionally, participants displayed an increased barbell loop at the first repetition during the ascending cluster protocol. Therefore, coaches should only use this programming strategy for highly trained athletes who have already developed proper weightlifting technique to avoid a suboptimal barbell trajectory during the power snatch training session. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
34. A comparison of three load-velocity based methods to estimate maximum overhead press performance in weightlifters.
- Author
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Soriano, Marcos A, Jiménez-Ormeño, Ester, Haff, G Gregory, Comfort, Paul, Giráldez-Costas, Verónica, Ruiz-Moreno, Carlos, and García-Ramos, Amador
- Subjects
WEIGHT lifters ,ERGOMETRY ,ANALYSIS of variance ,TEST validity ,BARBELLS ,PREDICTIVE validity - Abstract
This study aimed to evaluate whether lifting velocity can be used to estimate the overhead press one repetition maximum (1RM) and to explore the differences in the accuracy of the 1RM between three velocity-based methods. Twenty-seven weightlifters (16 men and 11 women) participated. The first session was used to test the overhead press 1RM. The second session consisted of an incremental loading test during the overhead press. The mean velocity was registered using a transducer attached to the barbell. A 1-way repeated-measures analysis of variance (ANOVA) with Bonferroni post hoc corrections was applied to the absolute differences between the actual and predicted 1RMs. Raw differences with 95% limits of agreement and ordinary least-products regressions were used to test the concurrent validity of the 1RM prediction methods with respect to the actual 1RM. The ANOVA did not reveal significant differences for the absolute differences respect to the actual 1RM between the three 1RM prediction methods (F = 3.2, p =.073). The absolute errors were moderate for the Multiple-Point (6.1 ± 3.7%), Two-Point
45−75 (8.6 ± 6.2%), and Two-Point45−90 methods (5.7 ± 4.0%). The validity analysis showed that all the 1RM prediction methods underestimated the actual 1RM (1.0–2.2 kg), but ordinary least-products regressions failed to show fixed or proportional bias. These results suggest that the Multiple-Point and Two-Point45−90 velocity-based methods might be viable tools to predict the overhead press 1RM in weightlifters, but practitioners are encouraged to use the direct 1RM for a more accurate prescription of the training loads. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
35. Learning effects of triple continuous jumping snatch intervention on the second pull of the snatch for novice lifters.
- Author
-
Wang, Shin-Yuan, Lan, Pei-Tzu, and Hsu, Tai-Ger
- Subjects
BARBELLS ,WEIGHT lifting ,COMPLICATED grief ,VELOCITY ,SHOULDER - Abstract
This study aimed to compare the effects of triple continuous jumping snatch (TCJS) intervention training on the technique and performance of novice lifters. Males (n = 22; age = 19.7 ± 0.9 years; height = 173.7 ± 6.1 cm; body mass = 76.3 ± 11.8 kg) who had no training experience in weightlifting were randomly assigned to a control (CG; n = 11) or an experimental (EG; n = 11) group, and trained three times a week for 8 weeks. The CG was trained in the snatch, and EG intervened with TCJS. In the initial state, t- tests and Hedges' effect sizes revealed significant and very large-to-nearly perfect differences (p < 0.001, g = 6.39) for barbell velocity while the barbell made contact with the body and the maximal barbell acceleration after contact (p < 0.001, g = 3.79) between CG and EG. Moreover, differences in the angle between the barbell and the shoulder prior to the turnover phase exhibited significant and moderate decreases in weeks 2, 6, and 8 (all p < 0.05, g = 0.63–0.98) by performing the snatch with the TCJS intervention. The TCJS not only impacts barbell velocity and acceleration immediately, but also reduces horizontal movement between the barbell and body. The results of this study demonstrated that the TCJS constitutes a superior training method for novice lifters to enhance the stability of techniques when compared with snatch. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
36. Chemo-enzymatic cascades producing 2,5-furandicarboxylic acid precursors viaD-gluconate "barbell oxidation" and dehydration.
- Author
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Chen, Jiao, Cai, Jiali, Sha, Feng, Sun, Wenjun, Lyu, Xilei, Chang, Yonghui, Cao, Fei, Zhao, Lili, Wu, Hongli, and Ouyang, Pingkai
- Subjects
- *
CARBONYL reductase , *BARBELLS , *TEREPHTHALIC acid , *DEHYDRATION , *OXIDATION - Abstract
As a potential substitute for petroleum-based terephthalic acid (TPA) in the manufacture of polyesters, 2,5-furandicarboxylic acid has been obtained through several feasible routes. Herein, a new chemo-enzymatic strategy for generating furan-2,5-dicarboxylic acid (FDCA) precursors from sodium gluconate via bio-oxidation and dehydration is presented. By coupling the bio-oxidation of gluconate 5-dehydrogenase with carbonyl reductase PsCR for cofactor regeneration, 5-keto- D -gluconic acid (5KGA), a specific product of D -gluconic acid bio-oxidation and a stable intermediate, was obtained in 99% yield. The statin intermediate ethyl (S)-4-chloro-3-hydroxybutanoate was simultaneously generated as a co-product via cycling cascade catalysis. Subsequently, the yield of the FDCA precursor n-butyl-5-formyl-2-furancarboxylate (nBu-FFCA) generated via 5KGA dehydration and esterification reached 77.9%. Key intermediate characterization and theoretical calculations revealed that the decarboxylation and dehydration of cyclic 5KGA to furfural was the main side-reaction that prevented a better yield of dehydrated 5KGA. This route demonstrates good sustainability and market competitiveness compared to the existing FDCA synthesis methods. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
37. Is Prescription of Specific Movement Form Necessary for Optimal Skill Development? A Nonlinear Pedagogy Approach.
- Author
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Lindsay, Riki S., Komar, John, Chow, Jia Yi, Larkin, Paul, and Spittle, Michael
- Subjects
- *
CLEAN energy , *BARBELLS , *MEDICAL prescriptions , *MOTOR ability - Abstract
Purpose: Nonlinear Pedagogy (NLP) proposes that skill development is a nonlinear process, advocating the integration of variability into practice to facilitate individualized movement patterns. However, the influence of a NLP for skills that emphasize a specific movement form is relatively unknown. This study aimed to investigate the impact of a NLP approach when learning a movement form based skill. Method: Sixteen beginners in the power clean (PC), were randomly assigned into a linear pedagogy (LP) condition receiving instructions that prescribed explicit movement form, and a NLP condition presented with analogy-based instructions and two task constraints. Both conditions completed seven lessons across 4-weeks. Results: There were no significant differences in the quantity of exploration, with both conditions demonstrating a similar range of movement patterns. These findings were coupled with a significant improvement in performance accuracy (reduced forward movement of the barbell; F × D) for both conditions. No significant differences were detected in the distribution of barbell trajectory types, with type one, three and four trajectories being exhibited to a similar degree in both conditions. Conclusion: Findings from this study suggests both NLP and LP pedagogies can successfully develop movement form based skills. Overall, both NLP and LP approaches appear to positively influence skill development. These findings have important implications for practitioners suggesting that deviations from instructed technique in learners (i.e., LP approach) do not negatively impact performance. However, further research is needed to determine whether these approaches can more effectively facilitate learners' search for movement solutions that "fit" their individual abilities. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
38. Mega moves and victorious lifts.
- Subjects
BARBELLS ,CRANES (Machinery) - Published
- 2024
39. JOINT STOCK COMPANY MANGISTAUMUNAYGAS invites tenders for Barbells
- Subjects
Barbells ,News, opinion and commentary - Abstract
JOINT STOCK COMPANY MANGISTAUMUNAYGAS, Kazakhstan has invited tenders for Barbells. Tender Notice No: 998656 Deadline: June 21, 2024 Copyright © 2011-2022 pivotalsources.com. All rights reserved. Provided by SyndiGate Media Inc. [...]
- Published
- 2024
40. Optimal barbell force-velocity profiles can contribute to maximize weightlifting performance.
- Author
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Sandau, Ingo and Granacher, Urs
- Subjects
- *
WEIGHT lifting , *BARBELLS , *ELITE athletes , *SENSITIVITY analysis - Abstract
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]
- Published
- 2023
- Full Text
- View/download PDF
41. Trends and Prospects in the Development of Gas-Lift and Bubble Equipment Designs.
- Author
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Vasiliev, P. D., Sidyagin, A. A., Stepykin, A. V., Kosyrev, V. M., and Bukharov, D. M.
- Subjects
- *
TECHNOLOGICAL innovations , *CHEMICAL milling , *BARBELLS , *MASS transfer - Abstract
The work is devoted to the review and analysis of gas-lift and bubble equipment designs. In particular, the paper presents the study, generalization, and critical appraisal of scientific and industrial innovations which reflect the currently existing trends in the development of gas-lift and bubble equipment designs. Based on the obtained data, the accumulated practical and theoretical experience in designing gas-lift and bubble equipment is systematized, and the possible prospects of their future development are identified. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
42. 185–215 GHz CMOS Frequency Doubler with a Single Row Staggered Distribution Layout Design.
- Author
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Dong, Ruibing and You, Chengwu
- Subjects
MANUFACTURING processes ,COMPLEMENTARY metal oxide semiconductors ,TRANSISTORS ,MILLIMETER waves ,BARBELLS ,DESIGN - Abstract
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 f
max 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]- Published
- 2023
- Full Text
- View/download PDF
43. A Novel DFA on AES: Based on Two–Byte Fault Model with Discontiguous Rows.
- Author
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Wan, Xusen, Zhang, Jinbao, Cheng, Shi, Wu, Weixiang, and Wang, Jiehua
- Subjects
ADVANCED Encryption Standard ,BLOCK ciphers ,INFORMATION technology security ,BARBELLS - Abstract
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 2
32 (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]- Published
- 2023
- Full Text
- View/download PDF
44. Effects of rest interval and training intensity on jumping performance: a systematic review and meta-analysis investigating post-activation performance enhancement.
- Author
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Yiyan Chen, Qing Su, Juan Yang, Gen Li, Shiyan Zhang, Yuanyuan Lv, and Laikang Yu
- Subjects
SQUAT (Weight lifting) ,VERTICAL jump ,BARBELLS ,SUBGROUP analysis (Experimental design) - Abstract
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]
- Published
- 2023
- Full Text
- View/download PDF
45. BIODIVERSITY AND HELMINTH COMMUNITIES OF Barbus cyclolepis Heckel, 1837 FROM CHERNA RIVER, BULGARIA.
- Author
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KUZMANOVA, Dimitrinka, CHUNCHUKOVA, Mariya, and KIRIN, Diana
- Subjects
- *
BIODIVERSITY , *BARBELLS , *HELMINTHS , *BIOINDICATORS , *FRESH water - Abstract
The study presents for the first time the Cherna River, southern Bulgaria, Aegean water basin, the results of research on the biological diversity and helminth communities of the Round-scaled barbell Barbus cyclolepis Heckel, 1837. 30 specimens of B. cyclolepis are studied. Infection by 5 species of helminths are found (Allocreadium isoporum (Loos, 1894); Bathybothrium rectangulum (Bloch, 1782); Caryophyllaeus laticeps (Pallas, 1781); Capillaria petruschewskii Zeder, 1800; Neoechinorhynchus rutili (Müller, 1780)). The infection indices and the dominant structure of helminth communities are presented. Basic biotic indices are determined. Helminth communities are analyzed at two levels: infracommunity and component community. All established parasite species are autogenous for the helminth communities of the Round-scaled barbell from the freshwater ecosystem of the Cherna River. New data for helminths and helminth communities of B. cyclolepis are presented. The bioindicator significance of helminths and helminth communities are discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2023
46. Velocity-Based Strength Training: The Validity and Personal Monitoring of Barbell Velocity with the Apple Watch.
- Author
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Achermann, Basil, Oberhofer, Katja, Ferguson, Stephen J., and Lorenzetti, Silvio R.
- Subjects
APPLE Watch ,STRENGTH training ,MOTION capture (Human mechanics) ,PERSONAL training ,SQUAT (Weight lifting) ,BARBELLS - Abstract
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]
- Published
- 2023
- Full Text
- View/download PDF
47. A Biomechanical Comparison between Squatbar ® and Olympic Barbell.
- Author
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Falch, Hallvard Nygaard, Kristiansen, Eirik, and van den Tillaar, Roland
- Subjects
- *
BIOMECHANICS , *WALKING , *EXERCISE , *BARBELLS , *ELECTROMYOGRAPHY - Abstract
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]
- Published
- 2023
- Full Text
- View/download PDF
48. How to Do the Dumbbell Deadlift Without Wrecking Your Lower Back.
- Author
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McCoy, Jenny
- Subjects
DUMBBELLS ,RANGE of motion of joints ,BARBELLS - Abstract
The article discusses the benefits, technique, and variations of the dumbbell deadlift exercise. The dumbbell deadlift primarily targets the posterior chain, including the hamstrings and glutes, but also engages the upper body and core. The article explains why dumbbell deadlifts can feel more challenging than barbell deadlifts, due to the range of motion and balance requirements. It also provides tips for avoiding common mistakes, incorporating the exercise into a workout routine, and progressing with heavier weights or different variations. The article is written by a journalist specializing in fitness and is published on self.com. [Extracted from the article]
- Published
- 2023
49. On the modular irregularity strength of some graph classes.
- Author
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Shulhany, Ahmad, Rukmayadi, Yazid, Maharani, Aprilia, Agusutrisno, Ahendyarti, Ceri, Ikhsan, Fajri, Nurhayati, Fardillah, Frena, Ramadhan, Rizky Nur, Raissa, Azarine Vashti Alpha, Samsudin, Achmad, Hasanah, Lilik, Yuliani, Galuh, Iryanti, Mimin, Kasi, Yohanes Freadyanus, Shidiq, Ari Syahidul, and Rusyati, Lilit
- Subjects
- *
LINEAR orderings , *INTEGERS , *BARBELLS , *GRAPH labelings - Abstract
Let G be a simple graph of order n, with no component of order two. Define an edge l-labeling θ:E(G)→{1,2,...,1}. Let xϵV(G), the weight of x is the sum of the l-labels of all its incident edges, denoted by α(x)=Σ░⟦θ(xy)⟧. The edge l-labeling is said modular irregular l-labeling of G if there exists a bijective weight α-function from V(G) to the group of integers modulo n. The smallest positive integer l such that G has a modular irregular l-labeling is said the modular irregularity strength of G, denoted by ms(G). Write ms(G)=∞, if G has no modular irregular strength. In this paper, we find ms of some graph classes, i.e. sunlet graphs, cycle barbell graphs, and m-Harary cycle graphs. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
50. A Comparison of Basic Training Variables in the Standard and Cambered Bar Bench Press Performed to Volitional Exhaustion.
- Author
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Matykiewicz, Patryk, Krzysztofik, Michał, and Zając, Adam
- Subjects
BENCH press ,TWO-way analysis of variance ,BARBELLS - Abstract
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]
- Published
- 2023
- Full Text
- View/download PDF
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