200-m Front Crawl Research Articles

The relationship between anthropometrical and physiological parameters of young elite boys in crawl and backstroke swimming

Objective: The aim of study was to investigate the relationship between anthropometrical and physiological characteristics with performance of elite young boys in crawl and backstroke. Methods: This study was a descriptive research, 122 elite young boy swimmers (mean age 12-13 years; height 1.540±8.24m; weight 47.820±6.84kg), who participated in 2018 national championship 2018 in Shiraz and completed satisfaction letter. Results: There was a significant negative relationship between foot length (r=-0.400,P=0.028), leg power (length jump)(r=-0.477,P=0.008), static balance (r=-0.380,P=0.038) and dynamic balance (inferior) (r=-0.367,P=0.046) with 100m crawl (n=30) time. Whereas, there was a significant positive relationship between leg action and reaction velocity (r=0.438,P=0.015) with 100m crawl time. There was a significant negative relationship between head circumference (r = -0.507,P=0.019) with 400m crawl (n=21) time. Whereas, there was a significant positive relationship between leg power (length jump) (r=0.543,P=0.011) with 400m crawl time. There was a significant negative relationship between trunk circumference at nipple height (r=0.381,P=0.038), trunk circumference at hip (r=-0.523,P=0.003), forearm length (r=-0.412,P=0.024), hand length (r=-0.400,P=0.029), and tight length (r=-0.461, P=0.010) with 100m backstroke (n=30) time. There was a significant negative relationship between seated height (r=-0.399,P=0.039), hand length (r=-0.400,P=0.039), and tibia length (r=-0.415,P=0.032) with 200m backstroke (n=27) time. Whereas, there was a significant positive relationship between trunk circumference at hip (r=0.600,P=0.001), and leg power (high jump) (r=0.408,P=0.035) with 200m backstroke time. Conclusion: There was the relationship between anthropometrical and physiological characteristics with performance of elite young boys in crawl and backstroke. It´s recommended that coaches and swimmers pay attention to results of the study at the earliest stages of adolescence for getting more success in reaching the peak of athletic performance.

The effects of plyometric jump training on jump and sport-specific performances in prepubertal female swimmers

Background/objectiveDry land-training (e.g., plyometric jump training) can be a useful mean to improve swimming performance. This study examined the effects of an 8-week plyometric jump training (PJT) program on jump and sport-specific performances in prepubertal female swimmers. MethodsTwenty-two girls were randomly assigned to either a plyometric jump training group (PJTG; n = 12, age: 10.01 ± 0.57 years, maturity-offset = -1.50 ± 0.50, body mass = 36.39 ± 6.32 kg, body height = 146.90 ± 7.62 cm, body mass index = 16.50 ± 1.73 kg/m2) or an active control (CG; n = 10, age: 10.50 ± 0.28 years, maturity-offset = -1.34 ± 0.51, body mass = 38.41 ± 9.42 kg, body height = 143.60 ± 5.05 cm, body mass index = 18.48 ± 3.77 kg/m2). Pre- and post-training, tests were conducted for the assessment of muscle power (e.g., countermovement-jump [CMJ], standing-long-jump [SLJ]). Sport-specific-performances were tested using the timed 25 and 50-m front crawl with a diving-start, timed 25-m front crawl without push-off from the wall (25-m WP), and a timed 25-m kick without push-off from the wall (25-m KWP). ResultsFindings showed a significant main effect of time for the CMJ (d = 0.78), the SLJ (d = 0.91), 25-m front crawl test (d = 2.5), and the 25-m-KWP (d = 1.38) test. Significant group × time interactions were found for CMJ, SLJ, 25-m front crawl, 50-m front crawl, 25-m KWP, and 25-m WP test (d = 0.29–1.63) in favor of PJTG (d = 1.34–3.50). No significant pre-post changes were found for CG (p > 0.05). ConclusionIn sum, PJT is effective in improving muscle power and sport-specific performances in prepubertal swimmers. Therefore, PJT should be included from an early start into the regular training program of swimmers.

Inter- and intra-rater reliability of swimming teachers with different skill levels, in different conditions, evaluating front crawl arm movement in non-expert swimmers

Abstract Aim: This study aimed (i) to test the inter-rater reliability of swimming teachers, (ii) to test the swimming teacher's discussion effect on inter-rater reliability and (iii) to verify the intra-rater swimming teacher's reliability. Method: Twenty-one learning swimmers (14.1 ± 5.1 years old) performed two 25-m front crawl courses at a comfortable speed without breathing between the sixth and 20-m, and had their displacements captured on film. Three swimming teachers with different academic backgrounds and skills evaluated the swimmer right upper limb using a 20-items checklist. In the 1st-step, teachers assessed 20-items and in 2nd-step discussed their particular evaluating criteria - selecting five items considered as the most relevant. The inter- and intra-rater reliability were tested using the Fleiss Kappa Coefficient. Results: In the 1st-step substantial reliability was found for item three and in movement descriptor for items three and 20. Nearly perfect reliability was found in the movement descriptor for item 13. In 2nd-step, moderate reliability was found only in the movement descriptor for item 20. Only the most experienced evaluator showed substantial intra-rater reliability for items four and 10 and moderate for item 20. Conclusion: The proposed discussion method did not cause the expected effect on inter-rater reliability. The swimming teacher with a higher degree and swimming skills showed better intra-rater reliability. Some items and movement descriptors proposed at the 20-items checklist can be used in practical settings.

Kinematic Differences in Shoulder Roll and Hip Roll at Different Front Crawl Speeds in National Level Swimmers.

Andersen, JT, Sinclair, PJ, McCabe, CB, and Sanders, RH. Kinematic differences in shoulder roll and hip roll at different front crawl speeds in National Level Swimmers. J Strength Cond Res 34(1): 20-25, 2020-Dry-land strength training is a common component of swimming programs; however, its efficacy is contentious. A common criticism of dry-land strength training for swimming is a lack of specificity. An understanding of movement patterns in swimming can enable dry-land strength training programs to be developed to elicit adaptations that transfer to improvements in swimming performance. This study aimed to quantify the range and velocity of hip roll, shoulder roll, and torso twist (produced by differences in the relative angle between shoulder roll and hip roll) in front crawl at different swimming speeds. Longitudinal torso kinematics was compared between sprint and 400-m pace front crawl using 3D kinematics of 13 elite Scottish front crawl specialists. The range (sprint: 78.1°; 400 m: 61.3°) and velocity of torso twist (sprint: 166.3°·s; 400 m: 96.9°·s) were greater at sprint than 400-m pace. These differences were attributed to reductions in hip roll (sprint: 36.8°; 400 m: 49.9°) without corresponding reductions in shoulder roll (sprint: 97.7°; 400 m: 101.6°) when subjects swam faster. Shoulder roll velocity (sprint: 190.9°·s; 400 m: 139.2°·s) and hip roll velocity (sprint: 75.5°·s; 400 m: 69.1°·s) were greater at sprint than 400-m pace due to a higher stroke frequency at sprint pace (sprint: 0.95 strokes·s; 400 m: 0.70 strokes·s). These findings imply that torques acting to rotate the upper torso and the lower torso are greater at sprint than 400-m pace. Dry-land strength training specificity can be improved by designing exercises that challenge the torso muscles to reproduce the torques required to generate the longitudinal kinematics in front crawl.

The 400-m Front Crawl Test: Energetic and 3D Kinematical Analyses.

The aim of the study was to verify the relative contributions of energetic and kinematic parameters to the performance in 400-m front crawl test. Fourteen middle-distance swimmers participated in the study. Oxygen consumption was measured directly and blood samples were collected to assay lactate concentration. Both oxygen consumption and lactate concentration were used to calculate the: (i) overall energy expenditure, (ii) anaerobic (alactic and lactic) and (iii) aerobic contributions. The mean centre of mass speed and intracycle velocity variation were determined through three-dimensional kinematic analysis. Mean completion time was 315.64±26.91s. Energetic contributions were as follows: 6.1±0.28% from alactic anaerobic metabolism, 5.9±0.63% from anaerobic lactic and 87.8±0.88% from aerobic. Mean intracycle velocity variation was 0.14±0.03. The results indicated that performance of 400-m test relies predominantly on aerobic power. Parameters such as lactate, mean speed, anaerobic lactic and alactic (kW) correlated with performance of 400-m test (p

Body composition and specific and general strength indices as predictors of 100-m front crawl performance

The purpose of this research was to examine the impact of body composition on the anaerobic ability to generate strength and power produced separately by upper and lower limbs during dry-land and in-water (propulsion force) tests. Further examination included the influence of all gathered anaerobic strength indices on the results of 100-m front crawl race. The study involved 26 male swimmers (age: 19.8 ± 2.48 years). Fat-free mass, total body water and muscle mass of arms, legs, and trunk were measured. Dry-land average work, maximal power generated in 40-second arm-cranking test, and work generated in 20 countermovement jumps were evaluated. The forces generated separately by arms and legs were assessed during 40-second tethered swimming. All indices of body composition were found strongly correlated with indices of average work and maximal power generated by arms and legs in dryland tests. Muscle mass of arms and trunk moderately and strongly (r = 0.44-0.64) influenced the force generated by arms in tethered swimming. There was no significance in the relationship of leg muscle mass and force generated by legs in tethered swimming. Significant relationships were observed between the results of the 100-m front crawl and the muscle mass of the arms, trunk, legs, as well as the average work and maximal power in the arm-cranking test (r: 0.39-0.54). The average impulse of arm force and maximal leg force in tethered swimming moderately and significantly correlated with 100-m swimming results. The study concludes the relevance of developing muscle mass balanced to the body size, which is involved in propulsion force production in sprint front crawl swimming.

The 400-m Front Crawl Test: Energetic and 3D Kinematical Analyses.

The aim of the study was to verify the relative contributions of energetic and kinematic parameters to the performance in 400-m front crawl test. Fourteen middle-distance swimmers participated in the study. Oxygen consumption was measured directly and blood samples were collected to assay lactate concentration. Both oxygen consumption and lactate concentration were used to calculate the: (i) overall energy expenditure, (ii) anaerobic (alactic and lactic) and (iii) aerobic contributions. The mean centre of mass speed and intracycle velocity variation were determined through three-dimensional kinematic analysis. Mean completion time was 315.64±26.91s. Energetic contributions were as follows: 6.1±0.28% from alactic anaerobic metabolism, 5.9±0.63% from anaerobic lactic and 87.8±0.88% from aerobic. Mean intracycle velocity variation was 0.14±0.03. The results indicated that performance of 400-m test relies predominantly on aerobic power. Parameters such as lactate, mean speed, anaerobic lactic and alactic (kW) correlated with performance of 400-m test (p <0.05). Multiple linear regressions indicated that mean centre of mass speed and anaerobic alactic (kW) determined the 400-m test performance (R2=0.92). Even though the T400 is characterized by aerobic metabolism, the anaerobic alactic component cannot be negligible at this competition level.

Influence of Morphology and Strength on Front Crawl Swimming Speed in Junior and Youth Age-Group Swimmers.

Strzała, M, Stanula, A, Krężałek, P, Ostrowski, A, Kaca, M, and Głąb, G. Influence of morphology and strength on front crawl swimming speed in junior and youth age-group swimmers. J Strength Cond Res 33(10): 2836-2845, 2019-This study, conducted in 2 male age groups, was aimed at analyzing the influence of body properties, dry-land strength and swimming strength on 50-m crawl (VCrawl). We examined 2 competitive groups, Youth (20.6 ± 1.05) and Junior (17.3 ± 0.59), based on (a) body mass (BM) and lean body mass (LBM), body height (BH) and total body length (TBL), and arm span (AS); (b) countermovement jump (CMJ) and maximum isometric strength of elbow and knee joints; and (c) tethered crawl strength. We hypothesized that a higher relationship of strength indices in younger swimmers in VCrawl and tethered swimming would be a better sprint performance predictor. The Junior group revealed a significant relationship between somatic traits (BM r = 0.63; BH r = 0.55; TBL r = 0.58; AS r = 0.52 with p ≤ 0.05 LBM r = 0.78; with p < 0.01) and VCrawl, whereas such interplay was not found in the Youth group. General dry-land strength indices CMJ (cm), CMJ (J) or isometric strength of knee joint muscle flexors and extensors (r = 0.57; r = 0.69; r = 0.56; r = 0.57, respectively) also significantly correlated with VCrawl only in the Junior group. The Junior group's tethered swimming strength had a higher but not a significant relationship with VCrawl. The Youth group instead achieved significantly higher VCrawl and stroke rate (SR). The SR revealed (r = 0.41, p = 0.014) a relationship with VCrawl only after the combination of both groups. This study demonstrates a better strength relationship with VCrawl in the younger Junior group. In the future, the evaluation of sprint swimming aptitudes, besides on the basis of somatic traits and properties of dry-land or water strength measurement, should be complemented by measurements of real sprint swimming technique parameters.

The Effect of a 6-Week Core Stability Training Program on the Stroke Index and Front Crawl Record of Male Swimmers

Objective For optimal performance of swimmers, it is necessary to determine a level for the functional interaction of upper and lower limbs. This level, created by more than 20 pairs of muscles, is the core of the body. The aim of this study was to investigate the effects of six weeks of core stability exercise on the stroke index and front crawl record of male swimmers. Methods In this quasi-experimental study, 24 male swimmers were selected by a convenience sampling method and randomly assigned into control (n=12) and exercise (n=12) groups. The core stability training was performed for 6 weeks, 3 sessions per week, each for 45-50 minutes. Before and after training, the stroke index and 100-m front crawl records of subjects were evaluated. For the within-group and between-group comparisons, the student t-test and ANCOVA were used, respectively. The significance level was set at P&lt;0.05. Results Six weeks of core stability exercise led to significant improvement in 100-m front crawl record in the exercise group. There was no significant difference in the mean scores of stroke index and 100-meter front crawl record between and within the two study groups. Conclusion Core stability exercise is recommended for dryland training of swimmers.

Recovery Time Profiling After Short-, Middle- and Long-Distance Swimming Performance.

Piras, A, Cortesi, M, Campa, F, Perazzolo, M, and Gatta, G. Recovery time profiling after short-, middle- and long-distance swimming performance. J Strength Cond Res 33(5): 1408-1415, 2019-We investigated cardiac autonomic responses and hemodynamic parameters on recovery time after short-, middle- and long-swimming performance. Ten male regional-level swimmers were tested to estimate time and frequency domains of arterial baroreflex sensitivity (BRS) and heart rate variability after 100, 200, and 400 m of front crawl. We found a BRS reduction for 90 minutes after a maximal 100- and 200-m front crawl event, meanwhile the reflex was restored back to the baseline value approximately 70 minutes after 400 m. The vagally mediated high-frequency power of R-R intervals was significantly reduced for 30 minutes after 400 m, and more than 90 minutes after 100 and 200 m, with a concomitant increase of sympathetic modulation. After 400 m, athletes have reduced their stroke volume for 50 minutes, which remained at the baseline level after 100 and 200 m. Heart rate was restored back after 90 minutes in all conditions, whereas total peripheral vascular resistance was significantly reduced for 50 minutes after 200 and 400 m, with a persistent reduction after 100 m. Time course of autonomic recovery after 3 different swimming performances is influenced by exercise intensity and duration, showing a rapid recovery after 400 m, an intermediate recovery after 200 m, and a significantly delayed recovery after a more strictly anaerobic performance like 100 m of front crawl. These results could encourage coaches to consider that athlete might be affected by the specific recovery time of the previous exercise performed, suggesting that the management of the exercise intensity, and appropriate monitoring of cardiac autonomic parameters might be helpful to know the physical condition of each athlete.

Physiological and Biomechanical Evaluation of a Training Macrocycle in Children Swimmers.

Physiological responses related to 400-m front crawl performance were examined in a 11-week training macrocycle in children 11.6 ± 1.2 years old. Fourteen girls and twenty-nine boys completed a maximum intensity 400-m test, at the beginning (Τ1) and at the end of four weeks of general preparation (Τ2), four weeks of specific preparation (Τ3), and three weeks of the competitive period (Τ4). Blood lactate (La), blood glucose (Glu) and heart rate were measured post effort. Stroke rate (SR), stroke length (SL) and stroke index (SI) were measured during the test. The 400-m time was decreased at T2, T3, and T4 compared to T1 by 4.2 ± 4.9, 7.5 ± 7.0, and 8.6 ± 7.3% (p < 0.05) and at T3 and T4 compared to T2 by 3.1 ± 4.3 and 4.2 ± 4.6%, respectively (p < 0.05). La was not different between tests (p > 0.05) and Glu was decreased at T3 compared to other testing moments (p < 0.05). SR, SL, and SI were higher at T3 and T4 compared to T1 (p < 0.05). SL and SI were also increased at T4 compared to T2 (p < 0.05). Performance changes from T1 to T2 were related to SL and SI changes (r = 0.45 and 0.83, p < 0.05), and subsequent changes between T2 to T3 were related to SR, SI, La, and Glu changes (r = 0.48, 0.68, 0.34, and 0.42, p < 0.05). Performance change from T3 to T4 was related to SL, SI, and La modifications (r = 0.34, 0.70, and 0.53, p < 0.05). Performance gains may be related to various biomechanical or physiological changes according to training macrocycle structure.

Effects of detraining in age-group swimmers performance, energetics and kinematics

ABSTRACTChanges in performance, energetics and kinematics during age-group swimmers off-season inform the prescription of training for the following season. Age-group swimmers (n = 15, age 14.3 ± 0.7 years) of equal maturational stage performed a 400-m front crawl (T400) before and after a four-weeks training cessation period. Performance-related energetic and kinematic variables were obtained controlling for anthropometric changes and non-swimming specific physical activities during off-season. T400 time decreased 3.8% (95%CI 1.4 to 6.1%; p < 0.01; d = 0.90) with non-specific physical activities (1814 ± 1989 MET-min·wk−1) accounting for ~40% of the underlying variance (p = 0.01; η2 = 0.40). Stroke rate and stroke index decreased despite similar stroke length and index of coordination values. Although mean response time, amplitude, maximal oxygen uptake, heart rate, total energy expenditure, metabolic power and energy cost were similar, aerobic contribution decreased by ~1.8% (−2.7 to −0.9%; p < 0.01; d = −1.19) and anaerobic lactic contribution increased by ~1.6% (0.8 to 2.5%; p < 0.01; d = 1.08) over the off-season. Impaired performance was mainly associated with a decreased stroke rate (r = −0.85 to −0.61; p ≤ 0.02), increased peak blood lactate (r = −0.52; p = 0.05) and fewer non-swimming specific physical activities performed during the off-season (r = −0.58; p = 0.03). The end-of-season cessation of training yielded moderate impairments in age-group swimmers performance-related energetic and kinematic factors, however non-specific physical activities can minimise fitness losses.

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, 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.

The Effects of Two Different Resisted Swim Training Load Protocols on Swimming Strength and Performance.

This study used a power rack device to evaluate the effects of 2 different approaches to resisted swim training loads on swimming strength and performance. Sixteen male, youth national-level swimmers (mean age, 16.22 ± 2.63 years; body height, 169 ± 10.20 cm; body mass, 61.33 ± 9.90 kg) completed a 6-week specific strength-training program, and were then randomly assigned to one of the two groups: a standard training group (GS, n = 8) and a flat pyramid-loading pattern group (GP, n = 8). Strength and power tests along with specific swimming tests (50-m crawl and 50-m competition-style time trials) were conducted at baseline (pre-test), before the third week (mid-test), and after 6 weeks of intervention (post-test). Isokinetic swim bench tests were conducted to obtain measurements of force production and power, and 1RM tests with the power rack system were conducted to measure the maximum drag load (MDL) and specific swimming power. Following 6 weeks of intervention, the mean MDL increased (p < 0.05) by 13.94%. Scores for the 50-m competition style and 50-m crawl time trials improved by 0.32% and 0.78%, respectively, in the GP; however, those changes were not statistically significant. The GS significantly increased their time in the 50-m competition style by 2.59%, and their isokinetic force production decreased by 14.47% (p < 0.05). The 6-week strength-training program performed with the power rack device in a pyramidal organization was more effective than a standard linear load organization in terms of producing improvements in the MDL; however, it did not produce significant improvements in performance. The use of a strength-training program with a pyramidal organization can be recommended for specific strength-training in young swimmers during a preparatory period. However, in our study, that program did not produce significant changes in 50-m crawl and main competition style performance.

Effects of Time of Day on Race Splits, Kinematics, and Blood Lactate During a 50-m Front Crawl Performance.

Lisbôa, FD, Raimundo, JAG, Pereira, GS, Ribeiro, G, de Aguiar, RA, and Caputo, F. Effects of time of day on race splits, kinematics, and blood lactate during a 50-m front crawl performance. J Strength Cond Res 35(3): 819-825, 2021-This study aimed to investigate the performance, race splits, metabolic, and stroke parameters during 2 successive 50-m front crawl under conditions simulating a competition. Eleven competitive male swimmers (20 ± 3 years, 182 ± 5 cm, and 77 ± 5 kg) performed 2 successive 50-m front crawl trials in a 50-m swimming pool at 10 am and 5 pm. Block time (tB), 15-m performance (t.15-m), and 50-m performance (t.50-m) were measured. Velocity (V), stroke rate (SR), stroke length (SL), and stroke index (SI) were measured at 3 time points during the trials. Pre-trial and post-trial blood samples were taken to determine blood lactate accumulation (Δ[Lac]). For t.50-m, the relative difference between 10 am and 5 pm reached 0.1% (p = 0.7; effect size [ES] = 0.02). Furthermore, no differences in tB (p = 0.12; ES = -0.28) and t.15-m (p = 0.39; ES = -0.16) were observed between periods. Both V (p = 0.11; ES = -0.14) and SI (p = 0.16; ES = 0.15) were also similar. Higher values of SR were recorded at 10 am (p = 0.03; ES = -0.32), whereas the morning values of SL were lower (p = 0.04; ES = 0.3). Δ[Lac] was not significantly different between periods (p = 0.07; ES = -0.27). Although time of the day did not impact performance in 2 successive 50-m front crawl performances, different stroke parameters profiles were observed during these trials. This may help coaches design specific warm-up exercises to enhance performance at different times of the day.

Acute biochemical and physiological responses to swimming training series performed at intensities based on the 400-m front crawl speed

The objective of this study was to compare blood lactate concentration (LAC), heart rate (HR), rating of perceived exertion (RPE), tryptophan (TRP), prolactin (PRL), nonesterified fatty acids (NEFA), branched-chain amino acids (BCAAs) plasma concentrations, and TRP/BCAAs ratio along interval training swimming series at 90 and 95% of the mean speed 400-m front crawl (s400). Fourteen male swimmers performed two-interval 400-m series (40 s of passive rest) at 90% (s90) and 95% (s95) of the s400, previously determined by 400-m front crawl all test. Summarized results are: (1) TRP, BCAAs, TRP/BCAAs ratio and NEFA were similar (p > 0.05) between rest and exhaustion conditions; (2) significant increases in LAC, PRL, HR and RPE (p < 0.05) for both series (s90 and s95). The findings of the present study indicate that during swimming series of interval training at 90 and 95% s400, there is maintenance of TRP, BCAA, TRP/BCAAs ratio and NEFA and increases in the RPE, PRL, LAC and HR, which can be explained by the intensities and the duration of exercise. Increased PRL can be related to central fatigue in these intensities.

Repetibilidade e aplicação de testes de nado estacionário para nadadores recreacionais

Tethered swimming tests are applied to evaluate propulsive forces in crawl stroke and may also be used to evaluate force applied by the movement of lower (leg kicking) and upper limbs (arm stroke). Considering the large number of recreational swimmers, this tool may be useful for coaches to evaluate the technique and force production by swimmers. As little attention has been paid to the application of these tests with recreational swimmers, the aims of this study were to verify the repeatability of the tethered swimming test for arm stroke, leg kicking and crawl stroke and to verify the relationship between performance in a 50-m test and in the tethered test with recreational swimmers. In this case, repeatability was defined as the agreement between the results of two successive evaluations. Ten male swimmers performed two 30-s maximal intensity tethered swimming tests with leg kicking, arm stroke and crawl stroke and three 50-m crawl stroke tests. Repeatability was found for mean force of all tests and for impulse evaluated in crawl stroke. Inverse relationship of the time to complete 50 m with the maximum and mean forces and with the impulse in the crawl stroke and an inverse relationship between time to complete 50 m and the mean force in the leg kicking were observed. Therefore, results from full tethered swimming tests applied with recreational swimmers may help swimming coaches.

How does buoyancy affect performance during a 200m maximum front crawl swim?

ABSTRACTWe investigated the rotational effect of buoyant force around the body’s transverse axis, termed buoyant torque, during a 200m front crawl maximal swim. Eleven male swimmers of national or international level participated. One stroke cycle (SC) for each 50m was recorded with two above and four below water cameras. The following variables were analysed: swimming velocity; absolute and normalised buoyant force; minimum, average and maximum buoyant torque; SC and arm recovery times. The average value of buoyant torque was higher in the first 50m (14.2 ± 4.5Nm) than in the following 150m (9.3 ± 4.1Nm~10.9 ± 4.5Nm) and was directed to raise the legs and lower the head throughout the race. The change in its magnitude seemed to be linked to the shorter time spent proportionally in arm recovery (first 50m: 27.6% of SC time; next 150m: 23.3–24.4% of SC time). Most swimmers had periods of the SC where buoyant torque was directed to sink the legs, which accounted to 10% of SC time in the first 50m and about twice this duration in the next 150m. These periods were observed exclusively at some instances when the recovering arm had entered the water while the opposite arm was still underwater.

Impact of Weekly Swimming Training Distance on the Ergogenicity of Inspiratory Muscle Training in Well-Trained Youth Swimmers

Lomax, M, Kapus, J, Brown, PI, and Faghy, M. Impact of weekly swimming training distance on the ergogenicity of inspiratory muscle training in well-trained youth swimmers. J Strength Cond Res 33(8): 2185-2193, 2019-The aim of this study was to examine the impact of weekly swimming training distance on the ergogenicity of inspiratory muscle training (IMT). Thirty-three youth swimmers were recruited and separated into a LOW and HIGH group based on weekly training distance (≤31 km·wk and >41 km·wk, respectively). The LOW and HIGH groups were further subdivided into control and IMT groups for a 6-week IMT intervention giving a total of 4 groups: LOWcon, LOWIMT, HIGHcon, and HIGHIMT. Before and after the intervention period, swimmers completed maximal effort 100- and 200-m front crawl swims, with maximal inspiratory and expiratory mouth pressures (PImax and PEmax, respectively) assessed before and after each swim. Inspiratory muscle training increased PImax (but not PEmax) by 36% in LOWIMT and HIGHIMT groups (p ≤ 0.05), but 100- and 200-m swims were faster only in the LOWIMT group (3 and 7% respectively, p ≤ 0.05). Performance benefits only occurred in those training up to 31 km·wk and indicate that the ergogenicity of IMT is affected by weekly training distance. Consequently, training distances are important considerations, among others, when deciding whether or not to supplement swimming training with IMT.

Taurine supplementation can increase lipolysis and affect the contribution of energy systems during front crawl maximal effort.

Taurine can affect the energy system metabolism, specifically the lipid metabolism, since an increase in lipid oxidation may promote carbohydrate savings. We hypothesized that taurine supplementation associated with high-intensity exercise could increase levels of lipolysis, benefiting swimmer performance. Nine male competitive swimmers performed two 400-m front crawl maximal efforts with a 1-week washout, and the athletes received 6 g of taurine (TAU) or placebo (PLA) supplementation 120min before performing the effort. Oxygen consumption and the contribution of the energy systems were analyzed post effort using a Quark CPET gas analyzer. Blood samples were collected before, and 5min post the effort for taurine and glycerol analysis. Immediately before and 3, 5, and 7min post the effort, blood samples from the earlobe were collected to determine lactate levels. An increase of 159% was observed in taurine plasma levels 120min post ingestion. Glycerol levels were higher in both groups post effort; however, the TAU condition promoted an 8% higher increase than the PLA. No changes were observed in swimmer performance or lactate levels; however, the percentage change in lactate levels (∆[La-]) was different (TAU: 9.36±2.78mmolL-1; PLA: 11.52±2.19mmolL-1, p=0.04). Acute taurine supplementation 120min before performing a maximal effort did not improve swimmer performance; however, it increased glycerol plasma levels and reduced both the ∆[La-] and lactic anaerobic system contribution.