scholarly journals CORRELATION ANALYSIS OF OLYMPIC-STYLE WEIGHTLIFTING EXERCISES AND VERTICAL JUMPS

2020 ◽  
Vol 13 (2) ◽  
pp. 26-32
Author(s):  
Tereza Králová ◽  
Jiří Gasior ◽  
Marián Vanderka ◽  
Jan Cacek ◽  
Tomáš Vencúrik ◽  
...  
Keyword(s):  
Body Weight ◽  
Power Output ◽  
Average Power ◽  
Correlation Coefficients ◽  
Jump Height ◽  
Arm Swing ◽  
Back Squat ◽  
Hands On ◽  
Average Power Output ◽  
Vertical Jumps

ABSTRACTPURPOSE Many types of vertical jumps (VJ) are commonly used to assess the development of the level of explosive strength of lower limbs achieved after a training period. This study is focused on comparing various parameters of different types of VJ with 1 RM in Olympic-style weightlifting, squat and deadlift with an Olympic bar.METHODS Twelve elite weightlifters (men=8; women=4; age 26±4 years, height = 173±8 cm; weight 93±23 kg; weight category from 64 kg to +109 kg) were tested for 1 RM in the following exercises: snatch, clean and jerk, deadlift, squat and variations of VJ on dynamometric plates (Kistler Force Plate). The variations of VJ were: squat jump with the arm swing (SJA) and non-arm swing (SJ), countermovement jump with the arm swing (CMJA) and non-arm swing (CMJ). The parameters compared for each type of VJ were: jump height (m), relative force (% of body weight), relative power (W/kg of body weight) and average power (W). For statistical analysis, the parametric Pearsons correlation coefficient with α=0.05 was used. RESULTS The results show a significant correlation between 1 RM in exercises with an Olympic bar (snatch, clean and jerk, back squat and deadlift) and the CMJ, CMJA, SJ and SJA only in the average power output (W) parameter (p<0.05). The significant correlation coefficients in the average power output (W) were for the CMJA and the snatch r=0.96 r2= 0.92, clean and jerk r=0.96 r2= 0.92, back squat r=0.97 r2= 0.94 and deadlift r=0.93 r2= 0.86; CMJ with hands on the hips and the snatch r=0.93 r2= 0.86, clean and jerk r= 0.93 r2= 0.86, back squat r= 0.95 r2= 0.90 and deadlift r= 0.94 r2= 0.88; for the SJA and the snatch r=0.8 r2= 0.64, clean and jerk r=0.81 r2= 0.65, back squat r=0.82 r2= 0.67 and deadlift r=0.78 r2= 0.60; for the SJ with hands on the hips and the snatch r= 0.76 r2= 0.57, clean and jerk r= 0.75 r2= 0.56, back squat r= 0.77 r2= 0.59 and deadlift r= 0.71 r2= 0.50. Significant correlation coefficients were not found for 1 RM in the snatch, clean and jerk, back squat and deadlift and the CMJ or SJ with and without arm swing in any of the following parameters: jump height (m), relative force (% of body weight), relative power output (W/kg of body weight).CONCLUSION The main finding is that the jump height (m) of the CMJ or SJ with or without arm swing did not correlate significantly with 1 RM in the snatch, clean and jerk, back squat and deadlift. Therefore, jump height measurement can be used as a motivation tool but not to predict maximum strength in Olympic bar exercises, or vice versa. We recommend using the average power output (W) parameter in the CMJ with using arms as a predictor of current performance level in exercises with an Olympic bar for men and women.Key words: snatch, clean and jerk, squat, deadlift, countermovement jump, squat jump

scholarly journals Control strategy of maximum vertical jumps: The preferred countermovement depth may not be fully optimized for jump height

2016 ◽  
Vol 52 (1) ◽  
pp. 85-94 ◽  
Author(s):  
Radivoj Mandic ◽  
Olivera M. Knezevic ◽  
Dragan M. Mirkov ◽  
Slobodan Jaric
Keyword(s):  
Control Strategy ◽  
Power Output ◽  
Jump Height ◽  
Basketball Players ◽  
Physically Active ◽  
Arm Swing ◽  
Testing Procedures ◽  
Leg Muscles ◽  
Task Strategy ◽  
Vertical Jumps

Abstract The aim of the present study was to explore the control strategy of maximum countermovement jumps regarding the preferred countermovement depth preceding the concentric jump phase. Elite basketball players and physically active non-athletes were tested on the jumps performed with and without an arm swing, while the countermovement depth was varied within the interval of almost 30 cm around its preferred value. The results consistently revealed 5.1-11.2 cm smaller countermovement depth than the optimum one, but the same difference was more prominent in non-athletes. In addition, although the same differences revealed a marked effect on the recorded force and power output, they reduced jump height for only 0.1-1.2 cm. Therefore, the studied control strategy may not be based solely on the countermovement depth that maximizes jump height. In addition, the comparison of the two groups does not support the concept of a dual-task strategy based on the trade-off between maximizing jump height and minimizing the jumping quickness that should be more prominent in the athletes that routinely need to jump quickly. Further research could explore whether the observed phenomenon is based on other optimization principles, such as the minimization of effort and energy expenditure. Nevertheless, future routine testing procedures should take into account that the control strategy of maximum countermovement jumps is not fully based on maximizing the jump height, while the countermovement depth markedly confound the relationship between the jump height and the assessed force and power output of leg muscles.

Stochastic Dynamics of a Piezoelectric Energy Harvester Subjected to Lévy Flight Excitations

2017 ◽  
Author(s):  
Subramanian Ramakrishnan ◽  
Collin Lambrecht ◽  
Connor Edlund
Keyword(s):  
Power Output ◽  
Stochastic Dynamics ◽  
Duffing Oscillator ◽  
Average Power ◽  
Coupled System ◽  
Random Excitation ◽  
Small Scale ◽  
Vibration Energy Harvesting ◽  
Piezoelectric Energy ◽  
Average Power Output

Vibration energy harvesting seeks to exploit the energy of ambient random vibration for power generation, particularly in small scale devices. Piezoelectric transduction is often used as a conversion mechanism in harvesting and the random excitation is typically modeled as a Brownian stochastic process. However, non-Brownian excitations are of potential interest, particularly in the nonequilibrium regime of harvester dynamics. In this work, we investigate the averaged power output of a generic piezoelectric harvester driven by Brownian as well as (non-Brownian) Lévy stable excitations both in the linear and the Duffing regimes. First, a coupled system of stochastic differential equations that model the electromechanical system are presented. Numerical simulation results (based on the Euler-Maruyama scheme) that show the average power output from the system under Brownian and Lévy excitations are presented for the cases where the mechanical degree of freedom behaves as a linear as well as a Duffing oscillator. The results demonstrate that Lévy excitations result in higher expectation values of harvested power. In particular, increasing the noise intensity leads to significant increase in power output in the Levy case when compared with Brownian excitations.

Theoretical Performance Analysis of Solar Chimney Power Plant for Kota Region of Rajasthan, India

2015 ◽  
Vol 787 ◽  
pp. 157-161 ◽  
Author(s):  
Zainab Akhtar ◽  
K.V.S. Rao
Keyword(s):  
Power Plant ◽  
Solar Radiation ◽  
Power Output ◽  
Average Power ◽  
Energy Generation ◽  
Solar Chimney ◽  
Minute Interval ◽  
Average Power Output ◽  
Solar Chimney Power Plant ◽  
Theoretical Performance

A solar chimney power plant (SCPP) sometimes also called 'solar updraft tower' is a part of the solar thermal group of indirect solar conversion technologies, utilizing a combination of solar air collector and central updraft tube or chimney to generate a solar induced convective flow which drives pressure staged turbines to generate electricity. In this paper the performance of a solar chimney power plant (SCPP) is evaluated if established in the Kota region of Rajasthan in India. Kota has high intensity of solar radiation with more than 270 sunny days in a year. To investigate the theoretical performance evaluation of the solar chimney power plant in Kota region, total energy generation and average power output for every ten minute interval has been calculated on the basis of solar radiation and temperature data provided by Centre for wind energy Technology (C-WET) available for the period from June 2011-May 2012 for every ten minute interval. Subsequently day wise and month wise calculations have been performed for energy generation and power output for the year June 2011 - May 2012. Further, annual average power output of SCPP is calculated at Kota for different sets of dimensions of SCPP and assuming different values of collector efficiency. Power produced at the plant established in Kota region is compared with power output estimated by J. Schlaich by their experience gained from prototype of SCPP in Manzanares, Spain. Land area required for solar chimney power plant if installed in Kota region of Rajasthan India is calculated for 200 MW capacity plant.

Mood and Cycling Performance in Response to Three Weeks of High-Intensity, Short-Duration Overtraining, and a Two-Week Taper

1999 ◽  
Vol 13 (4) ◽  
pp. 444-457 ◽  
Author(s):  
Bonnie G. Berger ◽  
Robert W. Motl ◽  
Brian D. Butki ◽  
David T. Martin ◽  
John G. Wilkinson ◽  
...  
Keyword(s):  
Short Duration ◽  
Power Output ◽  
High Intensity ◽  
Average Power ◽  
Interval Training ◽  
The United States ◽  
Cycling Performance ◽  
Mood Disturbance ◽  
Average Power Output ◽  
And Performance

This study examined changes in mood and performance in response to high-intensity, short-duration overtraining and a subsequent taper. Pursuit cyclists (N = 8) at the United States Olympic Training Center completed the POMS and simulated 4-km pursuit performance tests throughout a six-week period. The six-week period included a baseline week, three weeks of overtraining that consisted primarily of high-intensity interval training, and a two-week taper. Total Mood Disturbance (TMD) scores displayed a quadratic polynomial effect across the three weeks of overtraining (p < .01), with the highest TMD scores occurring in the second week. Average TMD scores were lower during the taper than at baseline (p < .02) and lower at taper than overtraining (p < .0005). Cycling performance (pursuit time and average power output) improved during the three weeks of overtraining; additional improvements were observed during the taper. There were no significant correlations between TMD and performance. However, pursuit time, average power output, and mood disturbance scores were at optimal levels throughout the taper period. These findings suggest that high-intensity, short-duration overtraining may not result in an overtraining syndrome in 4-km pursuit cyclists.

The Effect of Superoxygenated Water on Blood Gases, Lactate, and Aerobic Cycling Performance

2007 ◽  
Vol 2 (4) ◽  
pp. 377-385 ◽  
Author(s):  
Lars R. McNaughton ◽  
Steve Kenney ◽  
Jason Siegler ◽  
Adrian W. Midgley ◽  
Ric J. Lovell ◽  
...  
Keyword(s):  
Exercise Test ◽  
Power Output ◽  
Average Power ◽  
Rest Period ◽  
Cycling Performance ◽  
Exercise Tests ◽  
Double Blind ◽  
Maximal Power Output ◽  
Physiological Variables ◽  
Average Power Output

Context:Recently, superoxygenated-water beverages have emerged as a new purported ergogenic substance.Purpose:This study aimed to determine the effects of superoxygenated water on submaximal endurance performance.Methods:Eleven active male subjects, VO2max 52.6 ± 4.8 mL · kg−1 · min−1, height 180.0 ± 2.0 cm, weight 76.0 ± 7.0 kg, age 24 ± 1.0 y (mean ± SD), completed a 45-min cycle-ergometry exercise test at 70% of their previously predicted maximal power output with a 10-min rest period, followed by a 15-min time trial (TT). Thirty minutes before the exercise test subjects consumed 15 mL of either superoxygenated water (E) or placebo (P; water mixed with low-chlorine solution). Subjects then completed the test again a week later for the other condition (double-blind, randomized). The physiological variables measured during exercise were VO2, VCO2, respiratory-exchange ratio (RER), VE, PO2, PCO2, blood lactate (bLa–), and heart rate (HR). Mean distance covered and the average power output for the 15-min TT were also measured as performance indicators.Results:There were no significant differences in VO2, VCO2, RER, VE, bLa−, PO2, and HR (P > .05) during the exercise tests. Neither were there any significant improvements in the total distance covered (P 9.01 ± 0.74 km vs E 8.96 ± 0.68 km, P > .05) or the average power output (P 186.7 ± 35.8 W vs E 179.0 ± 25.9 W, P > .05) during the 15-min TT.Conclusion:Based on these results the authors conclude that consuming 15 mL of superoxygenated water does not enhance submaximal or maximal TT cycling performance.

Carbohydrate-Electrolyte Feedings and 1h Time Trial Cycling Performance

2004 ◽  
Vol 14 (5) ◽  
pp. 541-549 ◽  
Author(s):  
Ben Desbrow ◽  
Sally Anderson ◽  
Jennifer Barrett ◽  
Elissa Rao ◽  
Mark Hargreaves
Keyword(s):  
Power Output ◽  
High Intensity ◽  
Average Power ◽  
Time Trial ◽  
Cycling Performance ◽  
Dietary Regimen ◽  
Trained Subjects ◽  
Sports Drink ◽  
Average Power Output ◽  
Glucose Availability

The effects of a commercial sports drink on performance in high-intensity cycling was investigated. Nine well-trained subjects were asked to complete a set amount of work as fast as possible (time trial) following 24 h of dietary (subjects were provided with food, energy 57.4 ± 2.4 kcal/kg and carbohydrate 9.1 ± 0.4 g/kg) and exercise control. During exercise, subjects were provided with 14 mL/kg of either 6% carbohydrate-electrolyte (CHO-E) solution or carbohydrate-free placebo (P). Results showed that subjects’ performances did not greatly improve (time, 62:34 ± 6:44 min:sec (CHO-E) vs. 62:40 ± 5:35 min:sec (P); average power output, 283.0 ± 25.0 W (CHO-E) vs. 282.9 ± 29.3 W (P), P > 0.05) while consuming the sports drink. It was concluded that CHO-E consumption throughout a 1-h time trial, following a pre-exercise dietary regimen designed to optimize glucose availability, did not improve time or power output to a greater degree than P in well-trained cyclists.

The Isocapnic Buffering Phase and Mechanical Efficiency: Relationship to Cycle Time Trial Performance of Short and Long Duration

2005 ◽  
Vol 30 (1) ◽  
pp. 46-60 ◽  
Author(s):  
David J. Bentley ◽  
Veronica E. Vleck ◽  
Gregoire P. Millet
Keyword(s):  
Power Output ◽  
Average Power ◽  
Time Trial ◽  
Mechanical Efficiency ◽  
Incremental Test ◽  
Long Duration ◽  
Average Power Output ◽  
And Performance ◽  
The Relationship

The purpose of this study was to determine the relationship between the isocapnic buffer (βisocapnic) and hypocapnic hyperventilation (HHV) phases as well as performance in a short (20-min) and long (90-min) time trial (TT) in trained athletes. In addition, gross (GE, %) and delta (ΔE, %) efficiency were calculated and the relationship between these variables and the average power output (W) in each TT was determined. Thirteen male endurance athletes (Mean ± SD age 31 ± 6 yrs; body mass 75.6 ± 6.3 kg; height 185 ± 6 cm) completed a continuous incremental test to exhaustion for determination of the βisocapnic and HHV phases. A second submaximal test was used to determine GE and ΔE. The average power output (W) was measured in a 20-min and 90-min cycling TT. The βisocapnic phase (W) was significantly correlated to the average power output (W) in the 20-min TT (r = 0.58; p <  0.05), but not in the 90-min TT (r = 0.28). The HHV phase (W) was not significantly correlated to the average power output in the 20-min or 90-min TT. No significant correlation was found for GE or for ΔE and performance in the TT. The data from this study shows that βisocapnic together with HHV is not likely to be a useful indicator of cycle TT performance of 20- to 90-min duration. Furthermore, GE and ΔE determined from a submaximal incremental stepwise test are not related to cycling TT performance of different duration. Key words: incremental, correlation, metabolism, athletes, fatigue

Maximizing Average Power Output of an Airborne Wind Energy Generator Under Parametric Uncertainties

2015 ◽  
Author(s):  
Michelle A. Kehs ◽  
Chris Vermillion ◽  
Hosam K. Fathy
Keyword(s):  
Wind Speed ◽  
Wind Energy ◽  
Power Output ◽  
Average Power ◽  
Extremum Seeking ◽  
Energy Output ◽  
Wind Speeds ◽  
Average Power Output ◽  
The Difference ◽  
Optimal Average

This paper presents a controller for maximizing the time-averaged power output from an airborne wind energy generator in uncertain wind conditions. This system’s optimal energy output often involves flying in periodic figure-8 trajectories, but the precise optimal figure-8 shape is sensitive to environmental conditions, including wind speed. The literature presents controllers that are able to adapt to uncertainties, and this work expands on the current literature by using an extremum seeking based method. Extremum seeking is particularly well-suited for this application because of its well understood stability properties. In this work, extremum seeking is used to search through a family of optimal trajectories (computed offline) that correspond to discrete wind speeds. The controller is efficient in that it only searches for the optimum trajectory over the uncertain parameter (in this paper, wind speed). Results show that the controller converges to the optimal trajectory, provided it is initialized to a stable figure-8. The speed of convergence is dependent on the difference between the initial average power output and the optimal average power output.

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