Effect of Photobiomodulation on Critical Swimming Velocity: A Randomized, Crossover, Double-Blind, and Placebo-Controlled Study

2020 ◽  
pp. 1-8
Author(s):  
Cesar L. Teixeira ◽  
Paulo V. Mezzaroba ◽  
Fabiana A. Machado
Keyword(s):  
Swimming Performance ◽  
Acute Effect ◽  
Repeated Measurements ◽  
Controlled Study ◽  
Swimming Velocity ◽  
Front Crawl ◽  
Experimental Conditions ◽  
Double Blind ◽  
Physiological Factors ◽  
Prior Application

Purpose: To analyze the acute effect of photobiomodulation (PBM) on swimming critical velocity (CV). Methods: A total of 15 male federated swimmers (20.9 [2.4] y old) participated in this study. Three sets of front crawl were performed at distances of 100, 200, and 400 m to determine the CV under 3 experimental conditions: PBM (420 J), placebo (PLA), and control (C) in this randomized, crossover, double-blind, and placebo-controlled study. One-way analysis of variance for repeated measurements was used for statistical analyses. Results: The results showed that the prior application of PBM did not have ergogenic effects on CV and front crawl swimming performance: CV (PBM = 1.15 [0.15]; PLA = 1.20 [0.25]; C = 1.15 [0.14] m·s−1), swim time (ST) 100 m (PBM = 65.5 [6.3]; PLA = 65.2 [5.6]; C = 66.0 [5.9] s), ST 200 m (PBM = 148.5 [17.9]; PLA = 149.4 [16.4]; C = 150.1 [17.9] s), and ST 400 m (PBM = 327.7 [38.2]; PLA = 321.6 [47.7]; C = 329.5 [41.2] s). Conclusions: A PBM application prior to front crawl swimming test did not significantly modify the CV, ST, physiological factors of metabolic fatigue, perceptual, and front crawl stroke efficiency parameters in competition swimmers covering distances of 100, 200, and 400 m.

scholarly journals Beta alanine supplementation effects on metabolic contribution and swimming performance

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Matheus Silva Norberto ◽  
Ricardo Augusto Barbieri ◽  
Danilo Rodrigues Bertucci ◽  
Ronaldo Bucken Gobbi ◽  
Eduardo Zapaterra Campos ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Energy Demand ◽  
Swimming Performance ◽  
Controlled Study ◽  
Double Blind ◽  
Repeated Measures Anova ◽  
Beta Alanine ◽  
Before And After ◽  
The Difference ◽  
And Performance

Abstract Background Investigations of β-alanine supplementation shows effects on metabolic (aerobic and anaerobic) participation and performance on swimming by a possible blood acidosis buffering. Considering this background, the objective of the present study was to analyze the effects of β-alanine supplementation on metabolic contribution and performance during 400-m swim. Methods Thirteen competitive swimmers underwent a 6-week, double-blind placebo-controlled study, ingesting 4.8 g.day− 1 of β-alanine or placebo. Before and after the supplementation period, the total anaerobic contribution (TAn) and 30-s all-out tethered swimming effort (30TS) were assessed. Anaerobic alactic (AnAl) and lactic energy (AnLa) was assumed as the fast component of excess post-exercise oxygen consumption and net blood lactate accumulation during exercise (∆[La−]), respectively. Aerobic contribution (Aer) was determined by the difference between total energy demand and TAn. In addition to conventional statistical analysis (Repeated measures ANOVA; p > 0.05), a Bayesian repeated measures ANOVA was used to evidence the effect probability (BFincl). Results No differences and effects were found between groups, indicating no supplementation effects. Repeated measures ANOVA, with confirmation of effect, was indicate reduce in ∆Lactate (p: 0.001; BFincl: 25.02); absolute AnLa (p: 0.002; BFincl: 12.61), fatigue index (p > 0.001; BFincl: 63.25) and total anaerobic participation (p: 0.008; BFincl: 4.89). Conclusions Thus, the results demonstrated that all changes presented were evidenced as a result of exposure to the training period and β-alanine supplementation doesn’t affect metabolic contribution and performance during 400-m freestyle.

Pc.6 Acupressure for Dental Nausea: A Preliminary Report of a Prospective Randomised Double Blind Clinical Trial, Part 1

1997 ◽  
Vol 15 (1) ◽  
pp. 6-9 ◽  
Author(s):  
RAC Chate
Keyword(s):  
First Trimester ◽  
Small Sample ◽  
Cytotoxic Agents ◽  
Controlled Study ◽  
Double Blind ◽  
Double Blind Clinical Trial ◽  
First Trimester Of Pregnancy ◽  
The Difference ◽  
Prior Application ◽  
Randomised Controlled

Acupressure effectively reduces the amount of nausea experienced, both in the first trimester of pregnancy, and after either opiates or cytotoxic agents. The aim of this randomised, controlled study was to establish whether it could also reduce any sensation of nausea related to the taking of maxillary dental impressions. The sample comprised 8 males and 14 females, with a mean age of 14.64 years and whose self-registration of nausea following an impression was greater than 33% of a 100mm visual analogue. The test involved a second impression with prior application of pressure on either PC.6, the sixth point on the Chinese pericardial meridian, or a placebo point on the forearm of the patient's dominant limb. A random mental choice as to which point to press was made by each patient, and double blind conditions prevailed. After the withdrawal of the impression, another visual analogue was marked. Of the 9 patients who had used the placebo point during the test impression, there had been a mean reduction of 29% in the scale of nausea experienced. Of the 13 who had used the PC.6 acupressure point, the mean reduction was 30%. The difference was not significant. Three and a half minutes of acupressure on PC.6 did not reduce the sensation of nausea induced by tactile stimulation of the soft palate in this small sample of susceptible patients.

Performance of Young Male Swimmers in the 100-Meters Front Crawl

2010 ◽  
Vol 22 (2) ◽  
pp. 278-287 ◽  
Author(s):  
Fabrício de Mello Vitor ◽  
Maria Tereza Silveira Böhme
Keyword(s):  
Critical Speed ◽  
Swimming Performance ◽  
Anaerobic Power ◽  
Young Male ◽  
Front Crawl ◽  
Physiological Factors ◽  
Average Speed ◽  
Technical Factors ◽  
Swimming Technique

Youth swimming performance may be influenced by anthropometric, physiology and technical factors. The present paper examined the role of these factors in performance of 100m freestyle in swimmers 12–14 years of age (n = 24). Multiple regression analysis (forward method) was used to examine the variance of the 100 meters front crawl. Anaerobic power, swimming index and critical speed explained 88% (p < .05) of the variance in the average speed of 100 meters front crawl among young male pubertal swimmers. To conclude, performance of young swimmers in the 100 meters front crawl is determined predominantly by physiological factors and swimming technique.

Intracyclic Variation of Force and Swimming Performance

2018 ◽  
Vol 13 (7) ◽  
pp. 897-902 ◽  
Author(s):  
Pedro G. Morouço ◽  
Tiago M. Barbosa ◽  
Raul Arellano ◽  
João P. Vilas-Boas
Keyword(s):  
Swimming Performance ◽  
Time Trial ◽  
Velocity Variation ◽  
Swimming Velocity ◽  
Stroke Rate ◽  
Free Swimming ◽  
Front Crawl ◽  
Continuous Application ◽  
High Level ◽  
Maximal Effort

Context: In front-crawl swimming, the upper limbs perform alternating movements with the aim of achieving a continuous application of force in the water, leading to lower intracyclic velocity variation (dv). This parameter has been identified as a crucial criterion for swimmers’ evaluation. Purpose: To examine the assessment of intracyclic force variation (dF) and to analyze its relationship with dv and swimming performance. Methods: A total of 22 high-level male swimmers performed a maximal-effort 50-m front-crawl time trial and a 30-s maximal-effort fully tethered swimming test, which were randomly assigned. Instantaneous velocity was obtained by a speedometer and force by a strain-gauge system. Results: Similarity was observed between the tests, with dF attaining much higher magnitudes than dv (P < .001; d = 8.89). There were no differences in stroke rate or in physiological responses between tethered and free swimming, with a high level of agreement for the stroke rate and blood lactate increase. Swimming velocity presented a strong negative linear relationship with dF (r = −.826, P < .001) and a moderate negative nonlinear relationship with dv (r = .734, P < .01). With the addition of the maximum impulse to dF, multiple-regression analysis explained 83% of the free-swimming performance. Conclusions: Assessing dF is a promising approach for evaluating a swimmer’s performance. From the experiments, this new parameter showed that swimmers with higher dF also present higher dv, leading to a decrease in performance.

scholarly journals Relative Contribution of Arms and Legs in 30 s Fully Tethered Front Crawl Swimming

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Pedro G. Morouço ◽  
Daniel A. Marinho ◽  
Mikel Izquierdo ◽  
Henrique Neiva ◽  
Mário C. Marques
Keyword(s):  
Short Duration ◽  
High Intensity ◽  
Continuous Measurement ◽  
Swimming Performance ◽  
National Level ◽  
Cell System ◽  
Whole Body ◽  
Swimming Velocity ◽  
Front Crawl ◽  
Relative Contribution

The relative contribution of arm stroke and leg kicking to maximal fully tethered front crawl swimming performance remains to be solved. Twenty-three national level young swimmers (12 male and 11 female) randomly performed 3 bouts of 30 s fully tethered swimming (using the whole body, only the arm stroke, and only the leg kicking). A load-cell system permitted the continuous measurement of the exerted forces, and swimming velocity was calculated from the time taken to complete a 50 m front crawl swim. As expected, with no restrictions swimmers were able to exert higher forces than that using only their arm stroke or leg kicking. Estimated relative contributions of arm stroke and leg kicking were 70.3% versus 29.7% for males and 66.6% versus 33.4% for females, with 15.6% and 13.1% force deficits, respectively. To obtain higher velocities, male swimmers are highly dependent on the maximum forces they can exert with the arm stroke (r=0.77,P<0.01), whereas female swimmers swimming velocity is more related to whole-body mean forces (r=0.81,P<0.01). The obtained results point that leg kicking plays an important role over short duration high intensity bouts and that the used methodology may be useful to identify strength and/or coordination flaws.

scholarly journals The influence of different hand paddle size on 100-m front crawl kinematics

2012 ◽  
Vol 34 (1) ◽  
pp. 112-118 ◽  
Author(s):  
Daniel López-Plaza ◽  
Fernando Alacid ◽  
Pedro A. López-Miñarro ◽  
José M. Muyor
Keyword(s):  
Swimming Performance ◽  
Video Camera ◽  
Swimming Velocity ◽  
Stroke Rate ◽  
Front Crawl ◽  
Stroke Length ◽  
Elite Swimmers ◽  
The Mean

AbstractThe purpose of this study was to determine the influence of different sizes of hand paddles on kinematicparameters during a 100 m freestyle swimming performance in elite swimmers. Nine elite swimmers (19.1 ± 1.9 years)completed three tests of 100 m without paddles, with small paddles (271.27 cm2) and with large paddles (332.67 cm2),respectively. One video camera was used to record the performance during the three trials. The mean swimmingvelocity, stroke rate and stroke length were measured in the central 10 meters of each 50 m length. The results showedthat stroke length tended to increase significantly when wearing hand paddles (p < 0.05) during both the first andsecond 50 m sections whereas the increase in swimming velocity occurred only in the second 50 m (p < 0.05).Conversely, the stroke rate showed a slight decreasing trend with increasing paddle size. During the 100 m freestyletrial the stroke kinematics were changed significantly as a result of the increase in propelling surface size when handpaddles were worn.

Creatine Supplementation and Swimming Performance

1999 ◽  
Vol 9 (3) ◽  
pp. 251-262 ◽  
Author(s):  
Nicole Leenders ◽  
W. Michael Sherman ◽  
David R. Lamb ◽  
Timothy E. Nelson
Keyword(s):  
Swimming Performance ◽  
Creatine Supplementation ◽  
Baseline Period ◽  
Swimming Velocity ◽  
Double Blind ◽  
Men And Women ◽  
Double Blind Design

The purpose of this study was to determine if oral creatine (CR) ingestion, compared to a placebo (PL), would enable swimmers to maintain a higher swimming velocity across repeated interval sets over 2 weeks of supplementation. Fourteen female and 18 male university swimmers consumed a PL during a 2-week baseline period. Using a randomized, double-blind design, during the next 2 weeks subjects consumed either CR or PL. Swimming velocity was assessed twice weekly during 6 × 50-m swims and once weekly during 10 × 25-yd swims. There was no effect ofCR on the 10 × 25-yd interval sets for men and women and no effect on the 6 × 50-m interval sets for women. In contrast, for men, CR significantly improved mean overall swimming velocity in the 6 × 50-m interval after 2 weeks of supplementation, whereas PL had no effect. Although ineffective in women, CR supplementation apparently enables men to maintain a faster mean overall swimming velocity during repeated swims each lasting about 30 s; however, CR was not effective for men in repeated swims each lasting about 10-15 s.

scholarly journals Effect of supplementation of fermented milk drink containing probiotic Lactobacillus casei Shirota on the concentrations of aflatoxin biomarkers among employees of Universiti Putra Malaysia: a randomised, double-blind, cross-over, placebo-controlled study

2015 ◽  
Vol 115 (1) ◽  
pp. 39-54 ◽  
Author(s):  
Sabran Mohd Redzwan ◽  
Mohd Sokhini Abd Mutalib ◽  
Jia-Sheng Wang ◽  
Zuraini Ahmad ◽  
Min-Su Kang ◽  
...  
Keyword(s):  
Lactobacillus Casei ◽  
Group Analysis ◽  
Fermented Milk ◽  
Repeated Measurements ◽  
Urine Samples ◽  
Controlled Study ◽  
Double Blind ◽  
Probiotic Intervention ◽  
Blood And Urine Samples ◽  
Aflatoxin B

AbstractHuman exposure to aflatoxin is through the diet, and probiotics are able to bind aflatoxin and prevent its absorption in the small intestine. This study aimed to determine the effectiveness of a fermented milk drink containing Lactobacillus casei Shirota (LcS) (probiotic drink) to prevent aflatoxin absorption and reduce serum aflatoxin B1-lysine adduct (AFB1-lys) and urinary aflatoxin M1 concentrations. The present study was a randomised, double-blind, cross-over, placebo-controlled study with two 4-week intervention phases. In all, seventy-one subjects recruited from the screening stage were divided into two groups – the Yellow group and the Blue group. In the 1st phase, one group received probiotic drinks twice a day and the other group received placebo drinks. Blood and urine samples were collected at baseline, 2nd and 4th week of the intervention. After a 2-week wash-out period, the treatments were switched between the groups, and blood and urine samples were collected at the 6th, 8th and 10th week (2nd phase) of the intervention. No significant differences in aflatoxin biomarker concentrations were observed during the intervention. A within-group analysis was further carried out. Aflatoxin biomarker concentrations were not significantly different in the Yellow group. Nevertheless, ANOVA for repeated measurements indicated that AFB1-lys concentrations were significantly different (P=0·035) with the probiotic intervention in the Blue group. The 2nd week AFB1-lys concentrations (5·14 (sd 2·15) pg/mg albumin (ALB)) were significantly reduced (P=0·048) compared with the baseline (6·24 (sd 3·42) pg/mg ALB). Besides, the 4th week AFB1-lys concentrations were significantly lower (P<0·05) with probiotic supplementation than with the placebo. Based on these findings, a longer intervention study is warranted to investigate the effects of continuous LcS consumption to prevent dietary aflatoxin exposure.

scholarly journals Relationships Between Isokinetic Shoulder Evaluation and Fitness Characteristics of Elite French Female Water-Polo Players

2018 ◽  
Vol 64 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Nicolas Olivier ◽  
Frédéric N. Daussin
Keyword(s):  
Angular Velocity ◽  
Swimming Performance ◽  
Peak Torque ◽  
Swimming Velocity ◽  
Front Crawl ◽  
Dry Land ◽  
Water Polo ◽  
Adductor Muscles ◽  
High Level ◽  
The Relationship

Abstract Swimming and throwing are involved in water-polo player performance. These movements have a common biomechanical basis in the use of the internal shoulder rotation and adductor muscles. The aim of the study was to evaluate the relationship between shoulder isokinetic evaluation and throwing velocity as well as swimming performance in female water-polo players. Fifteen high level water-polo players completed two isokinetic shoulder evaluations to determine peak torque of shoulder rotators of the dominant shoulder (concentric and eccentric movements at an angular velocity of 60°·s-1 and concentric movements at an angular velocity of 240°·s-1) and shoulder extensors of both arms (concentric movements at an angular velocity of 60°·s-1 and 240°·s-1). Throwing velocity was measured using a radar gun placed 5 m behind the goal post. Front crawl swimming velocity was determined at 25 m, 100 m and 400 m distances. Concentric peak torque at 60°·s-1 and 240°·s-1 of internal rotators and eccentric peak torque at 60°·s-1 of external rotators were predictors of throwing velocity. The best model to explain the relationship between isokinetic evaluations and throwing velocity was obtained with concentric IR peak torque at 60°·s-1 and eccentric ER peak torque at 60°·s-1 (r2 = 0.52, p = 0.012). Relative total work done and peak torque of shoulder extensors were predictors of 25 m swimming velocity. Shoulder isokinetic evaluations correlate significantly with swimming performance and throwing velocity of female water-polo players. The results may help coaches to develop new strategies such as eccentric dry land training programs to increase both shoulder external rotators strength and throwing velocity.

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