Effects Of Static And Dynamic Stretching On Reaction Time And Performance In A Countermovement Jump

2009 ◽  
Vol 41 ◽  
pp. 85 ◽  
Author(s):  
Erica T. Perrier ◽  
Mark A. Hoffman
Keyword(s):  
Reaction Time ◽  
Countermovement Jump ◽  
Dynamic Stretching ◽  
And Performance

EFFECT OF REACTION TRAINING ON DURATION AND REACTION TIMES

2021 ◽  
Vol 7 (27) ◽  
pp. 86-92
Author(s):  
Tülin ATAN
Keyword(s):  
Reaction Time ◽  
Normal Distribution ◽  
Training Program ◽  
Reaction Times ◽  
Rank Test ◽  
Tennis Players ◽  
Before And After ◽  
Speed Performance ◽  
And Performance ◽  
Training Exercises

In this study, it was aimed to examine the effects of reaction training on reaction time and speed in tennis players. For this purpose a total of 18 tennis players; 9 male (age; 13.33 ± 1.80 years) and 7 female (13.85 ± 2.19 years) were voluntarily participated the study. In this study, the reaction training program, which was applied for 2 days a week for 12 weeks, was prepared in addition to tennis training. In the reaction training, exercises suitable for visual and auditory reaction were used. Before and after the 12-week reaction training, a 30 m speed running test and reaction time tests were performed. Whether the data showed normal distribution was analyzed with the Shapiro Wilk test and it was determined that the data did not show normal distribution. Mann Whitney U test was used in comparisons between the two groups. Wilcoxan Signd Rank test was used in the comparisons made before and after the training. As a result of the statistical analysis, it was seen that both the physical characteristics and performance parameters of males and females in our study group were not statistically different (p>0.05). For this reason, all subjects were taken into consideration regardless of gender in comparisons before and after tennis training. After the reaction training program applied to the subjects, it was determined that the 30 m speed performance values were shortened in duration compared to the pre-training period, that is, the speed improved (p <0.01). When the reaction time values were compared before and after the training program applied, it was seen that the reaction time values improved significantly after the training (p <0.01). As a result, reaction training performed in tennis players’ increases speed and reaction time performance. Reaction training is recommended in sports branches where this type of motor is important.

A Comparison of Different Modes of Morning Priming Exercise on Afternoon Performance

2016 ◽  
Vol 11 (6) ◽  
pp. 763-767 ◽  
Author(s):  
Mark Russell ◽  
Aden King ◽  
Richard. M. Bracken ◽  
Christian. J. Cook ◽  
Thibault Giroud ◽  
...  
Keyword(s):  
Reaction Time ◽  
Rugby Union ◽  
Jump Height ◽  
Countermovement Jump ◽  
Repeated Sprint ◽  
Mass Load ◽  
Hormone Responses ◽  
Sprint Cycling ◽  
Priming Exercise ◽  
Rugby Players

Purpose:To assess the effects of different modes of morning (AM) exercise on afternoon (PM) performance and salivary hormone responses in professional rugby union players.Methods:On 4 occasions (randomized, crossover design), 15 professional rugby players provided AM (~8 AM) and PM (~2 PM) saliva samples before PM assessments of countermovement-jump height, reaction time, and repeated-sprint ability. Control (passive rest), weights (bench press: 5 × 10 repetitions, 75% 1-repetition maximum, 90-s intraset recovery), cycling (6 × 6-s maximal sprint cycling, 7.5% body mass load, 54-s intraset recovery), and running (6 × 40-m maximal sprints, 20-s intraset recovery) interventions preceded (~5 h) PM testing.Results:PM sprint performance improved (P < .05) after weights (>0.15 ± 0.19 s, >2.04% ± 2.46%) and running (>0.15 ± 0.17 s, >2.12% ± 2.22%) but not cycling (P > .05). PM jump height increased after cycling (0.012 ± 0.009 m, 2.31% ± 1.76%, P < .001) and running (0.020 ± 0.009 m, 3.90% ± 1.79%, P < .001) but not weights (P = .936). Reaction time remained unchanged between trials (P = .379). Relative to control (131 ± 21 pg/mL), PM testosterone was greater in weights (21 ± 23 pg/mL, 17% ± 18%, P = .002) and running (28 ± 26 pg/mL, 22% ± 20%, P = .001) but not cycling (P = .072). Salivary cortisol was unaffected by AM exercise (P = .540).Conclusions:All modes of AM exercise improved at least 1 marker of PM performance, but running appeared the most beneficial to professional rugby union players. A rationale therefore exists for preceding PM competition with AM exercise.

scholarly journals Influence of Chronic Stroke on Functional Arm Reaching: Quantifying Deficits in the Ipsilesional Upper Extremity

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Savitha Subramaniam ◽  
Rini Varghese ◽  
Tanvi Bhatt
Keyword(s):  
Reaction Time ◽  
Upper Extremity ◽  
Movement Time ◽  
Chronic Stroke ◽  
Community Dwelling ◽  
Stroke Survivors ◽  
Initiation Time ◽  
Peak Acceleration ◽  
Movement Initiation ◽  
And Performance

Purpose. The purpose of this study was to quantify ipsilesional upper extremity (UE) stand-reaching performance (kinematics and kinetics) among chronic stroke survivors.Method. Community-dwelling chronic stroke survivors (n=13) and age-similar healthy adults (n=13) performed flexion- and abduction-reaching tasks. Surface EMG and acceleration were sampled using wireless sensors from the prime movers (anterior and middle deltoid) and provided performance-outcome (reaction time, burst duration, movement time, and movement initiation time) and performance-production (peak acceleration) measures and were then evaluated.Results. Individuals with chronic stroke demonstrated significantly reduced performance outcomes (i.e., longer reaction time, burst duration, movement time, and movement initiation time) and performance production ability (i.e., smaller peak acceleration) compared to their healthy counterparts (p< 0.05) for both flexion- and abduction-reaching movements.Conclusion. Our results are suggestive of post-stroke deficits in ipsilesional motor execution during a stand-reaching task. Based on these findings, it is essential to integrate ipsilesional UE training into rehabilitation interventions as this might aid functional reaching activities of daily living and could ultimately help community-dwelling chronic stroke survivors maintain their independent living.

Synthetic Technology and Performance of a Novel Fatty Alcohol Polyoxyethylene Carboxylate Surfactants

2011 ◽  
Vol 298 ◽  
pp. 163-168 ◽  
Author(s):  
Yuan Yuan Lei ◽  
Guo Zheng ◽  
Yu Sun ◽  
Yong Zhou
Keyword(s):  
Reaction Time ◽  
Optimum Condition ◽  
Sodium Hydroxide ◽  
Fatty Alcohol ◽  
Succinic Anhydride ◽  
Foam Stability ◽  
Raw Materials ◽  
Molar Ratio ◽  
New Type ◽  
And Performance

In this paper, with fatty alcohol polyoxyethylene (AEO9), succinic anhydride (SA) and sodium hydroxide as raw materials, a new type of fatty alcohol polyoxyethylene carboxylate surfactants (SAE9C-Na) was obtained by esterification and neutralizing effect. The influencing factors were researched and its surface properties were studied. The optimum condition of synthesis was determined: molar ratio of alcohol to acid was 1:1.1, reaction temperature was 85°C, reaction time was 60 min, under this condition, the yield could reach up to 95.8%. The results received from this experiment showed that SAE9C-Na had excellent surface activity and foaming and foam stability, whose emulsification and solubility enhancement were improved greatly.

Effect of the Adjuvants on the Properties of Superfine SnO2 Powders

2018 ◽  
Vol 281 ◽  
pp. 705-709
Author(s):  
Jie Guang Song ◽  
Lin Chen ◽  
Xian Jie Zhou ◽  
Xue Yang ◽  
Xin Peng Lou ◽  
...  
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Solar Cells ◽  
Reaction Time ◽  
Powder Material ◽  
Tin Oxide ◽  
Molar Ratio ◽  
New Type ◽  
And Performance ◽  
Holding Temperature

Ultrafine SnO2 is a new type of material, in the field of solar cells and semiconductors have a lot of use. To get different morphology and different properties of tin oxide powder material, making more applications in the field, the effect of the adjuvants on the properties of superfine SnO2 powders were distigated. Through the analysis of experimental results, the conclusions are shown the stronger the alkalinity of the auxiliary agent, the larger the grain size of the obtained particles and the more uniform the particles. When the molar ratio of salt to alkali is more than 1: 4, the amount of alkali is gradually reduced, the particle size is small, the morphology is not uniform and easy to agglomerate. When the molar ratio of salt to alkali is 1: 4, the smaller particle size is shown, the appearance morphology is uneven. The longer the reaction time, the more complete the grain, the more uniform the morphology. Under the condition of SnCl4 concentration of 0.05mol/L, reaction time is 4 days, salt and alkali molar ratio is 1: 4, holding temperature is 200°C, the auxiliary agent is NaOH, the size, shape and performance of synthesized SnO2 are the better.

scholarly journals THE RELATIONSHIP BETWEEN ACUTE MOOD, SLEEP, AND SEX ON NEUROCOGNITIVE PERFORMANCE POST-CONCUSSION IN ADOLESCENTS

2020 ◽  
Vol 8 (4_suppl3) ◽  
pp. 2325967120S0019
Author(s):  
Sara Stremlau ◽  
Richard Cameron Allred ◽  
Richard Gerkin ◽  
Steven Erickson ◽  
Jamie Pardini
Keyword(s):  
Reaction Time ◽  
Verbal Memory ◽  
Visual Memory ◽  
Cognitive Testing ◽  
Motor Speed ◽  
Neurocognitive Performance ◽  
Symptom Report ◽  
Mood Symptoms ◽  
Visual Motor ◽  
And Performance

Background: Both sleep disturbance and mood changes are common symptoms post-concussion (Sell & Rubeor, 2017). Studies have found these symptoms are correlated with poorer performance on neurocognitive testing (Kontos et al., 2012 and Kostyun et al., 2015). In addition, Brown et al., (2015) showed that females report more symptoms at both baseline and post-concussion compared to males on the Post-Concussion Scale and the Sport Concussion Assessment Tool 2. Hypothesis/Purpose: The purpose of this study is to investigate how a patient’s sex, as well as self-reported acute mood and sleep symptoms are related to neurocognitive performance in individuals with concussion. Methods: Data were acquired through IRB-approved retrospective chart review. Composite scores from the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) computerized evaluation and self-reported symptom scores on the Post-Concussion Symptom Scale were gathered for 1619 adolescents age 12-18 (49.3% female) who presented to a large metropolitan outpatient clinic for treatment of concussion. Results: Females endorsed higher overall symptoms (x=19.52, SD 19.37, median 13.0 for females; x=12.88, SD 15.89, median 7.0 for males; Mann-Whitney U Test p<0.001). This same pattern emerged for the mood and sleep symptom clusters (female mood mean=2.92, SD 4.51; male mood mean=1.64, SD 3.34; female sleep mean=1.59, SD 2.0; male sleep mean=1.11, SD 1.84; both Independent Samples Mann-Whitney U Tests ps<0.001). There were significant but modest negative correlations between mood symptoms and performance on verbal memory (r=-0.174), visual memory (r=-0.213), and visual motor speed (r=-0.146) composites (all ps<0.01). There was positive correlation between reaction time composite and mood symptoms (r=0.191). There were significant but modest negative correlations between sleep symptoms and performance on verbal memory (r=-0.171), visual memory (r=-0.184), and visual motor speed (r=-0.161) composites (all ps<0.01). There was a positive correlation between reaction time composite and sleep symptoms (r=0.196, p<0.01). Conclusion: Consistent with prior research, adolescent females reported more symptoms post-concussion, including total symptom score, mood symptoms, and sleep symptoms. Adolescents presenting with more mood and sleep symptoms demonstrated poorer performance on neurocognitive testing. However, given the modest nature of the correlation, a significant amount of variation in test performance is not explained by symptom report. Results from this study underscore the importance of a multidimensional concussion assessment that includes both symptom report and cognitive testing when working with pediatric athletes. This study also reinforces the importance of understanding potential effects of sleep, mood, and sex on concussion.

Start reaction time and performance at the sprint events in World Athletic Championships

2012 ◽  
Vol 12 (1) ◽  
pp. 112-118 ◽  
Author(s):  
Th. Pilianidis ◽  
N. Mantzouranis ◽  
A. Kasabalis
Keyword(s):  
Reaction Time ◽  
And Performance

scholarly journals Synthesis and Performance ofN-(Benzoyl) Stearic Acid Hydrazide

2012 ◽  
Vol 9 (2) ◽  
pp. 545-552 ◽  
Author(s):  
Yan-Hua Cai ◽  
Shun-Jiang Li
Keyword(s):  
Reaction Time ◽  
Stearic Acid ◽  
Reaction Temperature ◽  
Orthogonal Experiment ◽  
Acid Hydrazide ◽  
Semiempirical Method ◽  
Molar Ratio ◽  
H Nmr ◽  
And Performance ◽  
Benzoyl Hydrazine

N-(benzoyl) stearic acid hydrazide was synthesized from benzoyl hydrazine and stearyl chloride which was deprived from stearic acid via acylation. The structure of the compound had been characterized by FT-IR,1H NMR, at the same time, the structure of N-(benzoyl) stearic acid hydrazide was optimized by the semiempirical method PM3. The influence of the reaction ratio, reaction time and reaction temperature to the yield ofN-(benzoyl) stearic acid hydrazide was investigated by orthogonal experiment, and the optimized reaction condition was molar ratio of benzoyl hydrazine: stearyl chloride 1:1, reaction time 6 h, reaction temperature 70°C, and the yield was 92.9%. The TGA thermal analysis of N-(benzoyl) stearic acid hydrazide showed that thermal stability ofN-(benzoyl) stearic acid hydrazide was affected by heating rate, and theN-(benzoyl) stearic acid hydrazide enhanced the tensile strength, modulus and elongation at break of Poly(L-lactic acid)(PLLA).

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