Power output Dotaz Zobrazit nápovědu
The aims of this study were to create a regression model of the relationship between load and muscle power output and to determine an optimal load for maximum power output during a countermovement squat and a bench press. 55 males and 48 females performed power testing at 0, 10, 30, 50, 70, 90, and 100% of their individual one-repetition maximum (1-RM) in the countermovement squat and bench press exercises. Values for the maximum dynamic strength and load for each lift were used to develop a regression model in which the ratio of power was predicted from the ratio of the load for each type of lift. By optimizing the regression model, we predicted the optimal load for maximum muscle power. For the bench press and the countermovement squat, the mean optimal loads for maximum muscle output ranged from 50 to 70% of maximum dynamic strength. Optimal load in the acceleration phase of the upward movement of the two exercises appeared to be more important than over the full range of the movement. This model allows for specific determination of the optimal load for a pre-determined power output.
- MeSH
- biologické modely MeSH
- dospělí MeSH
- fyzická vytrvalost fyziologie MeSH
- kosterní svaly fyziologie MeSH
- lidé MeSH
- počítačová simulace MeSH
- přenos energie fyziologie MeSH
- regresní analýza MeSH
- statistické modely MeSH
- svalová kontrakce fyziologie MeSH
- zatížení muskuloskeletálního systému fyziologie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- práce podpořená grantem MeSH
The power supply for IEF based on features of the Cockcroft-Walton voltage multiplier (CW VM) is described in this work. The article describes a design of the IEF power supply, its electric characteristics, and testing by IEF analysis. A circuit diagram of the power supply included two opposite charged branches (each consisting of four voltage doublers). The designed CW VM was powered by 230 V/50 Hz alternate current and it generated up to 5 kV and 90 mW at the output. Voltage and current characteristics of the power supply were measured by known load resistances in the range from 10 kΩ to 1 GΩ, which is a common resistance range for IEF strip geometry. Further, the power supply was tested by a separation of a model mixture of colored pI markers using a 175 × 3 × 0.5 mm focusing bed. Automatically limited power load enabled analysis of samples without previous optimization of the focusing voltage or electric current time courses according to sample composition. Moreover, the developed power supply did not produce any intrinsic heat and was easy to set up with cheap and commonly available parts.
The purpose of this study was to examine how oxygen uptake (V . o2) in decrement-load exercise (DLE) is affected by changing rate of decrease in power output. DLE was performed at three different rates of decrease in power output (10, 20 and 30 watts·min-1: DLE10, DLE20 and DLE30, respectively) from power output corresponding to 90 % of peak V . o2. V . o2 exponentially increased and then decreased, and the rate of its decrease was reduced at low power output. The values of V . o2 in the three DLE tests were not different for the first 2 min despite the difference in power output. The relationship between V . o2 and power output below 50 watts was obtained as a slope to estimate excessive V . o2 (ex-V . o2) above 50 watts. The slopes were 10.0±0.9 for DLE10, 9.9±0.7 for DLE20 and 10.2±1.0 ml·min-1·watt-1 for DLE30. The difference between V . o2 estimated from the slope and measured V . o2 was defined as ex-V . o2. The peak value of ex-V . o2 for DLE10 (189±116 ml·min-1) was significantly greater than those for DLE20 and for DLE30 (93±97 and 88±34 ml·min-1). The difference between V . o2 in DLE and that in incremental-load exercise (ILE) below 50 watts (?V . o2) was greater in DLE30 and smallest in DLE10. There were significant differences in ?V . o2 among the three DLE tests. The values of ?V . o2 at 30 watts were 283±152 for DLE10, 413±136 for DLE20 and 483±187 ml·min-1 for DLE30. Thus, a faster rate of decrease in power output resulted in no change of V . o2 at the onset of DLE, smaller ex-V . o2 and greater ?V . o2. These results suggest that V . o2 is disposed in parallel in each motor unit released from power output or recruited in DLE.
- MeSH
- dospělí MeSH
- kosterní svalová vlákna * fyziologie MeSH
- lidé MeSH
- mladý dospělý MeSH
- statistika jako téma MeSH
- studenti MeSH
- svalová síla - dynamometr MeSH
- svalová síla * fyziologie MeSH
- tělesná námaha MeSH
- tělesná výchova MeSH
- tělesné váhy a míry MeSH
- zátěžový test * metody využití MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
This study evaluated the effects of ischemic conditioning on power output and bar velocity in the bench press exercise. Ten healthy males (age: 25 ± 2 years; body mass: 92 ± 8 kg; bench press one repetition maximum -1RM: 145 ± 13 kg), took part in two experimental sessions (with and without ischemia), 1 week apart in random and counterbalanced order. In the ischemic condition, cuffs placed around the upper part of the arms were inflated to 80% of arterial occlusion pressure before each set, while in the control condition there was no blood flow restriction. The exercise protocol included 5 sets of three repetitions each, against a resistance equal to 60% 1RM, with 5 min recovery intervals between sets. There was a main effect of condition for mean power output (MP) and mean bar velocity (MV) (p = 0.01), with overall MP being higher in ischemia than in control by 5.6 ± 4.1% (mean ± 90% compatibility limits), a standardized effect size (ES) of 0.51. Overall MV was also higher by 5.5 ± 4.0%, ES = 0.63. Peak power output (PP) and peak bar velocity (PV) were similar in set 1 of the control and ischemia condition (1039 ± 105 vs. 1054 ± 82 W; 684 ± 74 vs. 696 ± 53 W; 1.09 ± 0.07 vs. 1.12 ± 0.09 m/s; 0.81 ± 0.05 vs. 0.82 ± 0.05 m/s, p = 0.67 to 0.99, mean ± standard deviation). However, from set 3 onward (p = 0.03 to 0.001), PP and PV were higher in ischemia compared with control, with the highest difference observed in set 5 (10.9 ± 5.9%, ES = 0.73 for PP and 8.6 ± 4.6%; ES = 0.89 for PV). These results indicate that ischemia used before each set of the bench press exercise increases power output and bar velocity and this may be used as performance-enhancing stimulus during explosive resistance training.
- Publikační typ
- časopisecké články MeSH
This study is focused on finding the optimum load weight needed for the maximum mechanical power output during pressure exercise on a bench (bench press). The main objective is to identify the maximum load weight (% 1RM), with which the sample reaches the maximum mechanical power output (P% mm) during bench press exercise (BP). Results are recorded separately during the measurement and can help to determine the optimal load during strength training. A group of 15 highly trained athletes took part in the research, examined using experimental methods and measured with 3D kinematic and dynamic motion analysis. The group performed strength test with mechanical power output being measured at 0, 10, 30, 50, 70, 90 and 100% of one - recurrent maximum (1RM). Determined data was edited in Qualisys Track Manager and Visual Basic 3D / RT (C-Motion, Rockville, MD, USA) software. Maximal mechanical power output during the bench press exercise was achieved in the set of test subjects with a relative percentage of the load weight equal to 52% of 1RM.
- Klíčová slova
- 3D analýza pohybu, dynamická analýza pohybu, kinematická analýza pohybu,
- MeSH
- biomechanika fyziologie MeSH
- dospělí MeSH
- experimenty na lidech MeSH
- financování organizované MeSH
- kineziologie aplikovaná metody přístrojové vybavení využití MeSH
- lidé MeSH
- mladý dospělý MeSH
- odporový trénink metody MeSH
- pohyb těles MeSH
- sportovci klasifikace MeSH
- sportovní výkon MeSH
- sporty fyziologie klasifikace MeSH
- statistika jako téma MeSH
- svalová síla fyziologie MeSH
- zobrazování trojrozměrné metody přístrojové vybavení využití MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
In this study, we examined the impact of contrast movement tempo (fast vs. slow) on power output and bar velocity during the bench press exercise. Ten healthy men (age = 26.9 ± 4.1 years; body mass = 90.5 ± 10.3 kg; bench press 1RM = 136.8 ± 27.7 kg) with significant experience in resistance training (9.4 ± 5.6 years) performed the bench press exercise under three conditions: with an explosive tempo of movement in each of three repetitions (E/E/E = explosive, explosive, explosive); with a slow tempo of movement in the first repetition and an explosive tempo in the next two repetitions (S/E/E = slow, explosive, explosive); and with a slow tempo of movement in the first two repetitions and an explosive tempo in the last repetition (S/S/E = slow, slow, explosive). The slow repetitions were performed with a 5/0/5/0 (eccentric/isometric/concentric/isometric) movement tempo, while the explosive repetitions were performed with an X/0/X/0 (X- maximal speed of movement) movement tempo. During each experimental session, the participants performed one set of three repetitions at 60%1RM. The two-way repeated measures ANOVA showed a statistically significant interaction effect for peak power output (PP; p = 0.03; η2 = 0.26) and for peak bar velocity (PV; p = 0.04; η2 = 0.24). Futhermore there was a statistically significant main effect of condition for PP (p = 0.04; η2 = 0.30) and PV (p = 0.02; η2 = 0.35). The post hoc analysis for interaction revealed that PP was significantly higher in the 2nd and 3rd repetition for E/E/E compared with the S/S/E (p < 0.01 for both) and significantly higher in the 2nd repetition for the S/E/E compared with S/S/E (p < 0.01). The post hoc analysis for interaction revealed that PV was significantly higher in the 2nd and 3rd repetition for E/E/E compared with the S/S/E (p < 0.01 for both), and significantly higher in the 2nd repetition for the S/E/E compared with the S/S/E (p < 0.01). The post hoc analysis for main effect of condition revealed that PP and PV was significantly higher for the E/E/E compared to the S/S/E (p = 0.04; p = 0.02; respectively). The main finding of this study was that different distribution of movement tempo during a set has a significant impact on power output and bar velocity in the bench press exercise at 60%1RM. However, the use of one slow repetition at the beginning of a set does not decrease the level of power output in the third repetition of that set.
- Publikační typ
- časopisecké články MeSH
The purpose of this study was to determine the optimal load for the maximal power output during the acceleration phase of a power movement in bench press (BP) exercises of highly trained soccer players at the beginning of a competition period. Fifteen professional male soccer players with an average age of 26.1 ± 3.9 years, an average height of 183.3 ± 6.7 cm, an average body mass of 78.8 ± 7.2 kg, and an average 1 repetition maximum (1RM) of 83.3 ± 11.2 kg were employed as subjects in this study. Maximal mean power output during a BP at 0, 10, 30, 50, 70, and 90% of their 1RM was measured to determine whether an optimal load exists that allows for the attainment of maximal power output. Three-dimensional upper extremity kinematic data were collected. Two force plates embedded in the floor and positioned below the bench were used to measure contact forces between the bench and ground during the lift. A repeated-measures analysis of variance was performed to determine power output differences at different percentages of the 1RM. The results of this study indicated that loads of 50% of the 1RM resulted in greater mean power output during the complete positive power movement. Loads at 30 and 50% of the 1RM resulted in greater mean power output computed from the acceleration phase of the lift than did all loads and were not statistically different from each other. However, individual soccer players did not reach the maximum power output with the same relative load. In conclusion, when soccer players develop muscular power toward the end of when the most important competitions are scheduled, dynamic effort strength training with the range of load from 30 to 50% of 1RM BP should be used. During the competition period, a load of 50% of a 1RM should be used in a BP to maintain muscular power over a wide load range.
- MeSH
- biomechanika MeSH
- cvičení fyziologie MeSH
- dospělí MeSH
- fotbal fyziologie MeSH
- fyzická vytrvalost fyziologie MeSH
- horní končetina fyziologie MeSH
- kosterní svaly fyziologie MeSH
- lidé MeSH
- mladý dospělý MeSH
- sportovci MeSH
- svalová síla fyziologie MeSH
- vzpírání fyziologie MeSH
- zatížení muskuloskeletálního systému MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Jungwirth (Czech Republic) .3 -- Advances in industrial high power lasers -- H. Thornton (USA) .88 -- SESSION 15 -- High Power Laser Applications / -- Trends in high power laser applications Bohn (Germany) .103 -- Propulsion by laser power -- W. O. Lapucci (Italy) 110 -- Control of a high-power cw C02 laser output beam properties using an adaptive Fujioka (Japan) .157 -- High-efficiency mixing in high-power COIL.
1st ed. 209 s. ; 30 cm
- Konspekt
- Optika
- NLK Obory
- fyzika, biofyzika
- technika
