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1.
Beta alanine supplementation effects on metabolic contribution and swimming performance.
Norberto, MS, Barbieri, RA, Bertucci, DR, Gobbi, RB, Campos, EZ, Zagatto, AM, De Freitas, EC, Papoti, M
Journal of the International Society of Sports Nutrition. 2020;(1):40
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.
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2.
Effect of low- and high-carbohydrate diets on swimming economy: a crossover study.
Bestard, MA, Rothschild, JA, Crocker, GH
Journal of the International Society of Sports Nutrition. 2020;(1):64
Abstract
BACKGROUND Swimming economy refers to the rate of energy expenditure relative to swimming speed of movement, is inversely related to the energetic cost of swimming, and is as a key factor influencing endurance swimming performance. The objective of this study was to determine if high-carbohydrate, low-fat (HCLF) and low-carbohydrate, high-fat (LCHF) diets affect energetic cost of submaximal swimming. METHODS Eight recreational swimmers consumed two 3-day isoenergetic diets in a crossover design. Diets were tailored to individual food preferences, and macronutrient consumption was 69-16-16% and 16-67-18% carbohydrate-fat-protein for the HCLF and LCHF diets, respectively. Following each 3-day dietary intervention, participants swam in a flume at velocities associated with 50, 60, and 70% of their maximal aerobic capacity (VO2max). Expired breath was collected and analyzed while they swam which enabled calculation of the energetic cost of swimming. A paired t-test compared macronutrient distribution between HCLF and LCHF diets, while repeated-measures ANOVA determined effects of diet and exercise intensity on physiological endpoints. RESULTS Respiratory exchange ratio was significantly higher in HCLF compared to LCHF (p = 0.003), but there were no significant differences in the rate of oxygen consumption (p = 0.499) or energetic cost of swimming (p = 0.324) between diets. Heart rate did not differ between diets (p = 0.712), but oxygen pulse, a non-invasive surrogate for stroke volume, was greater following the HCLF diet (p = 0.029). CONCLUSIONS A 3-day high-carbohydrate diet increased carbohydrate utilization but did not affect swimming economy at 50-70% VO2max. As these intensities are applicable to ultramarathon swims, future studies should use higher intensities that would be more relevant to shorter duration events.
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3.
No Effect of Beetroot Juice Supplementation on 100-m and 200-m Swimming Performance in Moderately Trained Swimmers.
Esen, O, Nicholas, C, Morris, M, Bailey, SJ
International journal of sports physiology and performance. 2019;(6):706-710
Abstract
Purpose: Dietary nitrate supplementation has been reported to improve performance in kayaking and rowing exercise, which mandate significant recruitment of the upper-body musculature. Because the effect of dietary nitrate supplementation on swimming performance is unclear, the purpose of this study was to assess the effect of dietary nitrate supplementation on 100-m and 200-m swimming freestyle time-trial (TT) performance. Methods: In a double-blind, randomized crossover design, 10 moderately trained swimmers underwent 2 separate 3-d supplementation periods, with a daily dose of either 140 mL nitrate-rich (∼800 mg/d nitrate) or nitrate-depleted (PLA) beetroot juice (BRJ). After blood sampling on day 3, the swimmers performed both 200-m and 100-m freestyle swimming TTs, with 30 min recovery between trials. Results: Plasma nitrite concentration was greater after BRJ relative to PLA consumption (432 [203] nmol/L, 111 [56] nmol/L, respectively, P = .001). Systolic blood pressure was lowered after BRJ compared with PLA supplementation (114 [10], 120 [10] mm Hg, respectively P = .001), but time to complete the 200-m (BRJ 152.6 [14.1] s, PLA 152.5 [14.1] s) and 100-m (BRJ 69.5 [7.2] s, PLA 69.4 [7.4] s) freestyle swimming TTs was not different between BRJ and PLA (P > .05). Conclusions: Although 3 d of BRJ supplementation increased plasma nitrite concentration and lowered blood pressure, it did not improve 100-m and 200-m swimming TT performance. These results do not support an ergogenic effect of nitrate supplementation in moderately trained swimmers, at least for 100-m and 200-m freestyle swimming performance.
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4.
Effect of an 11-Week In-Water Training Program With Increased Resistance on the Swimming Performance and the Basic Kinematic Characteristics of the Front Crawl Stroke.
Gourgoulis, V, Valkoumas, I, Boli, A, Aggeloussis, N, Antoniou, P
Journal of strength and conditioning research. 2019;(1):95-103
Abstract
Gourgoulis, V, Valkoumas, I, Boli, A, Aggeloussis, N, and Antoniou, P. Effect of an 11-week in-water training program with increased resistance on the swimming performance and the basic kinematic characteristics of the front crawl stroke. J Strength Cond Res 33(1): 95-103, 2019-The purpose of the study was to assess the effect of an 11-week in-water training program with increased resistance on the swimming performance and the basic kinematic characteristics of the front crawl stroke in young female swimmers. Twelve swimmers were matched in pairs according to their best performance in 50-m front crawl swimming and then were randomly assigned to an experimental or to a control group. Both groups followed exactly the same swimming training program. The only exception was that the experimental group performed a sprint training section with increased resistance pulling a water parachute, whereas the control group performed the same section without parachute. Before and after the intervention program, the best performance of both groups in 50-, 100-, and 200-m front crawl swimming were assessed. Moreover, the basic kinematic characteristics of the stroke were calculated during 50-m front crawl swimming with maximal intensity. Two-way repeated measures analyses of variance revealed significant improvement in the best performance in all swimming distances only in the experimental group (3.22-7.26%). As far as the basic kinematic characteristics of the stroke are concerned, significant modifications were found only in the mean swimming velocity in the experimental group (2.18%), whereas no significant changes were observed in the stroke length, the stroke rate, and the duration of the propulsive, and nonpropulsive phases in both groups. Thus, the findings of the current study revealed a positive effect of the in-water resistance training program in the swimming performance of young female swimmers of moderate performance level, without any negative influence in the basic kinematic characteristics of the stroke.
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5.
Effects of Whole Body Vibration on Tibia Strength and Structure of Competitive Adolescent Swimmers: A Randomized Controlled Trial.
Gómez-Bruton, A, González-Agüero, A, Matute-Llorente, A, Julián, C, Lozano-Berges, G, Gómez-Cabello, A, Garatachea, N, Casajús, JA, Vicente-Rodríguez, G
PM & R : the journal of injury, function, and rehabilitation. 2018;(9):889-897
Abstract
BACKGROUND Swimming has no effect on bone mass or structure. Therefore, adolescent swimmers present similar bone strength values when compared to normo-active controls, and lower values when compared to weight-bearing athletes. It thus seems necessary to try to improve bone structure and strength of adolescent swimmers through a weight-bearing intervention in order to reduce the risk of suffering osteoporosis later in life. OBJECTIVE To evaluate the effects of a 6-month whole body vibration (WBV) intervention on bone strength and structure of adolescent swimmers. DESIGN Randomized controlled trial. SETTING Research center. PARTICIPANTS A total of 51 swimmers (14.4 ± 2.0 years) participated in the study. METHODS Swimmers were randomly allocated into 2 groups: 20 swimmers (9 females) who only performed their swimming training, and 31 swimmers (15 females) who performed their swimming training and received a WBV intervention (3.6-11.6 g) 3 times per week during 6 months (VIB). OUTCOME MEASUREMENTS Peripheral quantitative computed tomography was performed in the nondominant tibia of all swimmers at 4%, 38%, and 66% of the tibia length before and after the intervention. RESULTS No differences between groups in any bone structure variable were found at pre- or postintervention. Both groups presented similar improvements in time, and no group by time interactions were found, suggesting that the WBV intervention was not intense enough to achieve positive changes in bone strength or structure. CONCLUSION WBV, at the chosen intensities and durations, had no effect on adolescent swimmers' bone strength or structure. Future studies should test other weight-bearing interventions aiming to improve bone strength and structure of adolescent swimmers. LEVEL OF EVIDENCE II.
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6.
The effect of short-term coenzyme Q10 supplementation and pre-cooling strategy on cardiac damage markers in elite swimmers.
Emami, A, Tofighi, A, Asri-Rezaei, S, Bazargani-Gilani, B
The British journal of nutrition. 2018;(4):381-390
Abstract
Strenuous physical exercise and hyperthermia may paradoxically induce oxidative stress and adverse effects on myocardial function. The purpose of this study was to investigate the effect of 14-d coenzyme Q10 (CoQ10) supplementation and pre-cooling on serum creatine kinase-MB (CK-MB), cardiac Troponin I (cTnI), myoglobin (Mb), lactate dehydrogenase (LD), total antioxidant capacity (TAC), lipid peroxidation (LPO) and CoQ10 concentration in elite swimmers. In total, thirty-six healthy males (mean age 17 (sd 1) years) were randomly selected and divided into four groups of supplementation, supplementation with pre-cooling, pre-cooling and control. During an eighteen-session protocol in the morning and evening, subjects attended speed and endurance swimming training sessions for 5 km in each session. Blood sampling was done before (two stages) and after (two stages) administration of CoQ10 and pre-cooling. ANCOVA and repeated measurement tests with Bonferroni post hoc test were used for the statistical analysis of the data. There was no significant statistical difference among groups for the levels of CK-MB, cTnI, Mb, LD, TAC, LPO and CoQ10 at the presampling (stages 1 and 2) (P>0·05). However, pre-cooling and control groups show a significant increase in the levels of CK-MB, cTnI, Mb, LD and LPO compared with the supplementation and supplementation with pre-cooling groups in the post-sampling (stages 1 and 2) (P<0·05), except for the TAC and CoQ10. Consequently, CoQ10 supplementation prevents adverse changes of myocardial damage and oxidative stress during swimming competition phase. Meanwhile, the pre-cooling strategy individually has no desired effect on the levels of CK-MB, cTnI, Mb, LD, LPO, TAC and CoQ10.
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7.
In-Water Resisted Swim Training for Age-Group Swimmers: An Evaluation of Training Effects.
Kojima, K, Brammer, CL, Sossong, TD, Abe, T, Stager, JM
Pediatric exercise science. 2018;(1):124-131
Abstract
PURPOSE The purpose of this study is to compare the efficacy of resisted sprint swim training with that of nonresisted sprint swim training on 50-m freestyle competition time (Vmax50) in age-group swimmers. METHODS Twenty-four age-group swimmers (age 10.6-14.9 y) were divided into resisted or nonresisted sprint swim training groups and completed a sprint swim training intervention 2 times per week for 10 weeks. Repeated 10-m sprints with progressively increasing resistance were used to determine measures of swim power. Skeletal muscle mass was estimated using B-mode ultrasound. Maturity status was estimated using predicted adult height (%Htadult) and maturity offset. RESULTS A 2-way repeated-measures analysis of variance revealed no group × time interaction for measured variables. Vmax50 was correlated with skeletal muscle mass and swim power variables, but no significant relationship was found between relative changes in these variables. Estimated maturity status (%Htadult) appeared to be associated with initial measures of swim power and performance variables. CONCLUSIONS Ten weeks of resisted sprint swim training was not any more effective than nonresisted sprint swim training at improving sprint swim performance in age-group swimmers.
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8.
Effect of Dietary Nitrate Supplementation on Swimming Performance in Trained Swimmers.
Lowings, S, Shannon, OM, Deighton, K, Matu, J, Barlow, MJ
International journal of sport nutrition and exercise metabolism. 2017;(4):377-384
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Abstract
Nitrate supplementation appears to be most ergogenic when oxygen availability is restricted and subsequently may be particularly beneficial for swimming performance due to the breath-hold element of this sport. This represents the first investigation of nitrate supplementation and swimming time-trial (TT) performance. In a randomized double-blind repeated-measures crossover study, ten (5 male, 5 female) trained swimmers ingested 140ml nitrate-rich (~12.5mmol nitrate) or nitrate-depleted (~0.01mmol nitrate) beetroot juice. Three hours later, subjects completed a maximal effort swim TT comprising 168m (8 × 21m lengths) backstroke. Preexercise fractional exhaled nitric oxide concentration was significantly elevated with nitrate compared with placebo, Mean (SD): 17 (9) vs. 7 (3)p.p.b., p = .008. Nitrate supplementation had a likely trivial effect on overall swim TT performance (mean difference 1.22s; 90% CI -0.18-2.6s; 0.93%; p = .144; d = 0.13; unlikely beneficial (22.6%), likely trivial (77.2%), most unlikely negative (0.2%)). The effects of nitrate supplementation during the first half of the TT were trivial (mean difference 0.29s; 90% CI -0.94-1.5s; 0.46%; p = .678; d = 0.05), but there was a possible beneficial effect of nitrate supplementation during the second half of the TT (mean difference 0.93s; 90% CI 0.13-1.70s; 1.36%; p = .062; d = 0.24; possibly beneficial (63.5%), possibly trivial (36.3%), most unlikely negative (0.2%)). The duration and speed of underwater swimming within the performance did not differ between nitrate and placebo (both p > .30). Nitrate supplementation increased nitric oxide bioavailability but did not benefit short-distance swimming performance or the underwater phases of the TT. Further investigation into the effects of nitrate supplementation during the second half of performance tests may be warranted.
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Do 6 months of whole-body vibration training improve lean mass and bone mass acquisition of adolescent swimmers?
Gómez-Bruton, A, González-Agüero, A, Matute-Llorente, A, Julián, C, Lozano-Berges, G, Gómez-Cabello, A, Casajús, JA, Vicente-Rodríguez, G
Archives of osteoporosis. 2017;(1):69
Abstract
UNLABELLED Swimming has little effect on bone mass. Therefore, adolescent swimmers should complement their water training with a short and intense weight-bearing training, aiming to increase their bone acquisition. Forty swimmers performed a six-month whole-body vibration (WBV) training. WBV had no effect on adolescent swimmers' bone mass or lean mass. PURPOSE The aims of the present study were to evaluate the effects of a whole-body vibration (WBV) intervention on bone mineral density (BMD), bone mineral content (BMC) and lean mass (LM) in adolescent swimmers. METHODS Forty male and female adolescent swimmers (VIB; mean age 14.2 ± 1.9 years) completed the WBV protocol that consisted of 15 min of training 3 days per week during a 6-month period (ranging from 3.6 to 11.6 g), while 23 swimmers (SWI; mean age 15.0 ± 2.2 years) continued with their regular swimming training alone. VIB were divided into tertiles according to training compliance in order to evaluate if any dose-effect relation existed. BMD, BMC and LM were measured longitudinally by dual energy X-ray at the whole body, lumbar-spine and hip. RESULTS No group by time interactions and no differences in change percentage were found for BMD, BMC or LM in any of the measured variables. The mean change percentage of the subtotal body (whole body minus the head) for VIB and SWI, respectively, was 2.3 vs. 2.4% for BMD, 5.7 vs 5.7% for BMC and 7.3 vs. 8.0% for lean mass. Moreover, no indication for dose-response was observed. CONCLUSIONS The proposed WBV protocol had no effect on BMD, BMC and LM in adolescent swimmers. Other types of training should be used in this population to improve both bone and lean mass.
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10.
Multiple-Transportable Carbohydrate Effect on Long-Distance Triathlon Performance.
Rowlands, DS, Houltham, SD
Medicine and science in sports and exercise. 2017;(8):1734-1744
Abstract
UNLABELLED The ingestion of multiple (2:1 glucose-fructose) transportable carbohydrate in beverages at high rates (>78 g·h) during endurance exercise enhances exogenous carbohydrate oxidation, fluid absorption, gut comfort, and performance relative to glucose alone. However, during long-distance endurance competition, athletes prefer a solid-gel-drink format, and the effect size of multiple-transportable carbohydrate is unknown. PURPOSE This study aimed to determine the effect of multiple-transportable carbohydrate on triathlon competition performance when ingested within bars, gels, and drinks. METHODS A double-blind randomized controlled trial was conducted within two national-body sanctioned half-ironman triathlon races held 3 wk apart in 74 well-trained male triathletes (18-60 yr; >2 yr competition experience). Carbohydrate comprising glucose/maltodextrin-fructose (2:1 ratio) or standard isocaloric carbohydrate (glucose/maltodextrin only) was ingested before (94 g) and during the cycle (2.5 g·km) and run (7.8 g·km) sections, averaging 78.6 ± 6.6 g·h, partitioned to bars (25%), gels (35%), and drink (40%). Postrace, 0- to 10-unit Likert-type scales were completed to assess gut comfort and energy. RESULTS The trial returned low dropout rate (9%), high compliance, and sensitivity (typical error 2.2%). The effect of multiple-transportable carbohydrate on performance time was -0.53% (95% confidence interval = -1.30% to 0.24%; small benefit threshold = -0.54%), with likelihood-based risk analysis supporting adoption (benefit-harm ratio = 48.9%:0.3%; odds ratio = 285:1). Covariate adjustments for preexercise body weight and heat stress had negligible impact performance. Multiple-transportable carbohydrate possibly lowered nausea during the swim and bike; otherwise, effects on gut comfort and perceived energy were negligible. CONCLUSIONS Multiple-transportable (2:1 maltodextrin/glucose-fructose) compared with single-transportable carbohydrate ingested in differing format provided a small benefit to long-distance triathlon performance, inferred as adoption worthy. Large sample in-competition randomized trials offer ecological validity, high participant throughput, compliance, and sensitivity for evaluation of health and performance interventions in athletes.