Well-trained Swimmers Research Articles

Body Composition Relationship to Performance, Cardiorespiratory Profile, and Tether Force in Youth Trained Swimmers.

This study sought to analyze the relationship between regional body composition, swimming performance, and aerobic and force profile determined through tethered swimming in well-trained swimmers. Eleven male and five female swimmers were involved in the study and underwent the following evaluations: (1) body composition, assessed by the dual-energy X-ray absorptiometry method (DXA); (2) swimming performance, determined for 200, 400, 800, and 1.500 m front-crawl swimming; (3) a tethered swimming force test to determine maximum and mean force (Fmax and Fmean); and (4) an incremental tethered swimming test for the aerobic profile determination of the swimmers. Oxygen uptake (VO2) was directly measured by an automatic and portable system (K4b2 Cosmed, Italy). The fat-free mass (lean mass + bone mineral content, LM+BMC) in lower and upper limbs (UL_LM+BMC: 6.74 ± 1.57 kg and LL_LM+BMC: 20.15 ± 3.84 kg) positively correlated with all indexes of aerobic conditioning level, showing higher coefficients to the indexes representing the ability to perform at high aerobic intensities (VO2max: 49.2 ± 5.9 mL·kg-1·min-1 and respiratory compensation point (RCP): 43.8 ± 6.0 mL·kg-1·min-1), which attained 0.82 and 0.81 (with VO2max), 0.81 and 0.80 (with RCP). The S200 (1.48 ± 0.13 m·s-1) was significantly correlated to Trunk_LM+BMC (r = 0.74), UL_LM+BMC (r = 0.72), Total_LM+BMC (r = 0.71), and LL_LM+BMC (r = 0.64). This study highlights that regional body composition plays an important role in swimming, and body segment analysis should be considered instead of the total body. Tethered swimming may represent a useful method for force and aerobic assessment, aiming at training control and performance enhancement.

Acute ventilatory responses to swimming at increasing intensities.

Physical exercise is a source of stress to the human body, triggering different ventilatory responses through different regulatory mechanisms and the aquatic environment imposes several restrictions to the swimmer, particularly regarding the restricted ventilation. Thus, we aimed to assess the acute ventilatory responses and to characterize the adopted breathing patterns when swimming front crawl at increasing intensity domains. Eighteen well-trained swimmers performed 7 × 200 m front crawl (0.05 m∙s-1 velocity increments) and a maximal 100 m (30 s rest intervals). Pulmonary gas exchange and ventilation were continuously measured (breath-by-breath) and capillary blood samples for lactate concentration ([La-]) analysis were collected at rest, during intervals and at the end of the protocol, allowing the identification of the low, moderate, heavy, severe and extreme intensity domains. With the swimming velocity rise, respiratory frequency (f R), [La-] and stroke rate (SR) increased ([29.1-49.7] breaths∙min-1, [2.7-11.4] mmol∙L-1, [26.23-40.85] cycles; respectively) and stroke length (SL) decreased ([2.43-2.04] m∙min-1; respectively). Oxygen uptake (VO2), minute ventilation (VE), carbon dioxide production (VCO2) and heart rate (HR) increased until severe ([37.5-53.5] mL∙kg-1∙min-1, [55.8-96.3] L∙min-1, [32.2-51.5] mL∙kg-1∙min-1 and [152-182] bpm; respectively) and stabilized from severe to extreme (53.1 ± 8.4, mL∙kg-1∙min-1, 99.5 ± 19.1 L∙min-1, 49.7 ± 8.3 mL∙kg-1∙min-1 and 186 ± 11 bpm; respectively) while tidal volume (VT) was similar from low to severe ([2.02-2.18] L) and decreased at extreme intensities (2.08 ± 0.56 L). Lastly, the f R/SR ratio increased from low to heavy and decreased from severe to the extreme intensity domains (1.12 ± 0.24, 1.19 ± 0.25, 1.26 ± 0.26, 1.32 ± 0.26 and 1.23 ± 0.26). Our findings confirm a different ventilatory response pattern at extreme intensities when compared to the usually evaluated exertions. This novel insight helps to understand and characterize the maximal efforts in swimming and reinforces the importance to include extreme efforts in future swimming evaluations.

Time limit and V̇O2 kinetics at maximal aerobic velocity: Continuous vs. intermittent swimming trials.

The time sustained during exercise with oxygen uptake (V̇O2) reaching maximal rates (V̇O2peak) or near peak responses (i.e., above second ventilatory threshold [t@VT2) or 90% V̇O2peak (t@90%V̇O2peak)] is recognized as the training pace required to enhance aerobic power and exercise tolerance in the severe domain (time-limit, tLim). This study compared physiological and performance indexes during continuous and intermittent trials at maximal aerobic velocity (MAV) to analyze each exercise schedule, supporting their roles in conditioning planning. Twenty-two well-trained swimmers completed a discontinuous incremental step-test for V̇O2peak, VT2, and MAV assessments. Two other tests were performed in randomized order, to compare continuous (CT) vs. intermittent trials (IT100) at MAV until exhaustion, to determine peak oxygen uptake (Peak-V̇O2) and V̇O2 kinetics (V̇O2K). Distance and time variables were registered to determine the tLim, t@VT2, and t@90%V̇O2peak tests. Blood lactate concentration ([La−]) was analyzed, and rate of perceived exertion (RPE) was recorded. The tests were conducted using a breath-by-breath apparatus connected to a snorkel for pulmonary gas sampling, with pacing controlled by an underwater visual pacer. V̇O2peak (55.2 ± 5.6 ml·kg·min−1) was only reached in CT (100.7 ± 3.1 %V̇O2peak). In addition, high V̇O2 values were reached at IT100 (96.4 ± 4.2 %V̇O2peak). V̇O2peak was highly correlated with Peak-V̇O2 during CT (r = 0.95, p < 0.01) and IT100 (r = 0.91, p < 0.01). Compared with CT, the IT100 presented significantly higher values for tLim (1,013.6 ± 496.6 vs. 256.2 ± 60.3 s), distance (1,277.3 ± 638.1 vs. 315.9 ± 63.3 m), t@VT2 (448.1 ± 211.1 vs. 144.1 ± 78.8 s), and t@90%V̇O2peak (321.9 ± 208.7 vs. 127.5 ± 77.1 s). V̇O2K time constants (IT100: 25.9 ± 9.4 vs. CT: 26.5 ± 7.5 s) were correlated between tests (r = 0.76, p < 0.01). Between CT and IT100, tLim were not related, and RPE (8.9 ± 0.9 vs. 9.4 ± 0.8) and [La−] (7.8 ± 2.7 vs. 7.8 ± 2.8 mmol·l−1) did not differ between tests. MAV is suitable for planning swimming intensities requiring V̇O2peak rates, whatever the exercise schedule (continuous or intermittent). Therefore, the results suggest IT100 as a preferable training schedule rather than the CT for aerobic capacity training since IT100 presented a significantly higher tLim, t@VT2, and t@90%V̇O2peak (∼757, ∼304, and ∼194 s more, respectively), without differing regards to [La−] and RPE. The V̇O2K seemed not to influence tLim and times spent near V̇O2peak in both workout modes.

The Impact of COVID-19 on the Preparation for the Tokyo Olympics: A Comprehensive Performance Assessment of Top Swimmers.

Background: The Olympic preparation of athletes has been highly influenced by COVID and post-COVID syndrome. As the complex screening of athletes is essential for safe and successful sports, we aimed to repeat the 2019-year sports cardiology screening of the Olympic Swim Team before the Olympics and to compare the results of COVID and non-COVID athletes. Methods: Patient history, electrocardiogram, laboratory tests, body composition analysis, echocardiography, cardiopulmonary exercise test (CPET) were performed. We used time-ranking points to compare swimming performance. Results: From April 2019, we examined 46 elite swimmers (24 ± 4 years). Fourteen swimmers had COVID infection; all cases were mild. During CPET there was no difference in the performance of COVID (male: VO2 max 55 ± 4 vs. 56.5 ± 5 mL/kg/min, p = 0.53; female: VO2 max 54.6 ± 4 vs. 56 ± 5.5 mL/kg/min, p = 0.86) vs. non-COVID athletes (male VO2 max 56.7 ± 5 vs. 55.5 ± 4.5 mL/kg/min, p = 0.50; female 49.6 ± 3 vs. 50.7 ± 2.6 mL/kg/min, p = 0.47) between 2019 and 2021. When comparing the time results of the National Championships, 54.8% of the athletes showed an improvement (p = 0.75). Conclusions: COVID infection with short-term detraining did not affect the performance of well-trained swimmers. According to our results, the COVID pandemic did not impair the effectiveness of the preparation for the Tokyo Olympics.

Can an Incremental Step Test Be Used for Maximal Lactate Steady State Determination in Swimming? Clues for Practice.

We aimed to compare the velocity, physiological responses, and stroke mechanics between the lactate parameters determined in an incremental step test (IST) and maximal lactate steady state (MLSS). Fourteen well-trained male swimmers (16.8 ± 2.8 years) were timed for 400 m and 200 m (T200). Afterwards, a 7 × 200-m front-crawl IST was performed. Swimming velocity, heart rate (HR), blood lactate concentration (BLC), stroke mechanics, and rate of perceived exertion (RPE) were measured throughout the IST and in the 30-min continuous test (CT) bouts for MLSS determination. Swimming velocities at lactate threshold determined with log-log methodology (1.34 ± 0.06 m∙s−1) and Dmax methodology (1.40 ± 0.06 m∙s−1); and also, the velocity at BLC of 4 mmol∙L−1 (1.36 ± 0.07) were not significantly different from MLSSv, however, Bland–Altman analysis showed wide limits of agreement and the concordance correlation coefficient showed poor strength of agreement between the aforementioned parameters which precludes their interchangeable use. Stroke mechanics, HR, RPE, and BLC in MLSSv were not significantly different from the fourth repetition of IST (85% of T200), which by itself can provide useful support to daily practice of well-trained swimmers. Nevertheless, the determination of MLSSv, based on a CT, remains more accurate for exercise evaluation and prescription.

Response of Blood Biomarkers to Sprint Interval Swimming.

To evaluate and compare the effects of 2 sprint interval training (SIT) sets of different distances on biochemical markers indicative of metabolism, stress, and antioxidant capacity in competitive swimmers and, to investigate the potential influence of gender on these markers. Twenty-four adolescent, well-trained swimmers (12 men and 12 women) participated in the study. In a random and counterbalanced order, the swimmers completed 2 SIT sets (8 × 50m and 8 × 25m) in freestyle with maximal intensity on different days. Work-to-rest ratio was 1:1 in both sets. Blood samples were drawn preexercise, immediately postexercise, and 1hour postexercise to evaluate the effects of the SIT sets on a number of biochemical parameters. Swimming speed was higher at 8 × 25m. The 2 SIT sets induced significant increases in lactate, glucose, insulin, glucagon, cortisol, and uric acid (P ≤ .001). No differences in these parameters were found between sets, except for irisin (higher in 8 × 50m; P = .02). Male swimmers were faster and had higher lactate and uric acid concentrations, as well as lower reduced glutathione concentration, than female swimmers (P < .01). The 2 swimming SIT sets induced increases in most of the biochemical markers studied. The 2-fold difference between sets in distance did not differentiate the effects of sprint interval exercise on most biochemical parameters. Thus, low-volume SIT sets seem to be effective stimuli for competitive swimmers.

Associations Between Heart Rate Variability-Derived Indexes and Training Load: Repeated Measures Correlation Approach Contribution.

Davletyarova, K, Vacher, P, Nicolas, M, Kapilevich, LV, and Mourot, L. Associations between heart rate variability-derived indexes and training load: repeated measures correlation approach contribution. J Strength Cond Res 36(7): 2005-2010, 2022-This study aimed to evaluate whether similar associations between indexes derived from heart rate variability (HRV) analyses and training load (TL) could be obtained by using the commonly used Pearson correlation technique and the repeated measures correlation (rmcorr). Fourteen well-trained swimmers (18.5 ± 1.6 years) participated. The training period lasted 4 weeks with a gradual increase in TL. Daily external TL (exTL) and internal TL (inTL) were summed to obtain a weekly TL, and HRV analyses were performed every Saturday morning. During the 4-week period, exTL and inTL increased (p < 0.05) together with a decrease (p < 0.05) in heart rate and an increase (p < 0.05) of cardiac parasympathetic indexes. No significant correlation was found using Pearson correlation while significant associations were found using rmcorr; considering exTL, positive (mean R-R interval [MeanRR], root mean square of differences between successive RR interval [RMSSD], low frequency [LF], high frequency [HF], instantaneous beat-to-beat variability [SD1], continuous beat-to-beat variability [SD2], SD1/SD2; r from 0.59 to 0.46, p value from <0.001 to 0.002) and negative (mean heart rate [meanHR]; r = -0.55, p < 0.001) associations were found. Considering inTL, positive (MeanRR, RMSSD, LF, HF, HFnu, SD1, SD2, SD1/SD2; r from 0.56 to 0.34, p-value from <0.001 to 0.025) and negative (meanHR, LFnu, LF/HF; r from -0.49 to -0.34, p value from 0.001 to 0.025) associations were found. The rmcorr statistical method was able to show associations between parasympathetic indexes and TL contrary to Pearson correlation analysis. Because rmcorr is specifically designed to investigate within-individual association for paired measures assessed on 2 or more occasions for multiple individuals, it should constitute a tool for future training monitoring researches based on a repeated-measures protocol.

Formula: see text] kinetics and energy contribution in simulated maximal performance during short and middle distance-trials in swimming.

This study aims to analyze swimmers' oxygen uptake kinetics ([Formula: see text]K) and bioenergetic profiles in 50, 100, and 200m simulated swimming events and determine which physiological variables relate with performance. Twenty-eight well-trained swimmers completed an incremental test for maximal oxygen uptake (Peak-[Formula: see text]) and maximal aerobic velocity (MAV) assessment. Maximal trials (MT) of 50, 100, and 200-m in front crawl swimming were performed for [Formula: see text]K and bioenergetic profile. [Formula: see text]K parameters were calculated through monoexponential modeling and by a new growth rate method. The recovery phase was used along with the blood lactate concentration for bioenergetics profiling. Peak-[Formula: see text] (57.47 ± 5.7mlkg-1min-1 for male and 53.53 ± 4.21mlkg-1min-1 for female) did not differ from [Formula: see text]peak attained at the 200-MT for female and at the 100 and 200-MT for male. From the 50-MT to 100-MT and to the 200-MT the [Formula: see text]K presented slower time constants (8.6 ± 2.3s, 11.5 ± 2.4s and 16.7 ± 5.5s, respectively), the aerobic contribution increased (~ 34%, 54% and 71%, respectively) and the anaerobic decreased (~ 66%, 46% and 29%, respectively), presenting a cross-over in the 100-MT. Both energy systems, MAV, Peak-[Formula: see text], and [Formula: see text] peak of the MT's were correlated with swimming performance. The aerobic energy contribution is an important factor for performance in 50, 100, and 200-m, regardless of the time taken to adjust the absolute oxidative response, when considering the effect on a mixed-group regarding sex. [Formula: see text]K speeding could be explained by a faster initial pacing strategy used in the shorter distances, that contributed for a more rapid increase of the oxidative contribution to the energy turnover.

Is V̇O2peak a Valid Estimation of V̇O2max in Swimmers with Physical Impairments?

ABSTRACTPurpose: Peak and maximal oxygen uptake ( and , respectively) are used in assessing aerobic power. For swimmers with physical impairments, it is unclear whether the physiological variables obtained in 200-m and Nx200-m tests are similar. The objective of this study is to assess the validity of as an estimator of and complementary physiological variables, in particular, carbon dioxide production (), respiratory exchange ratio (RER), minute-ventilation ( and absolute (HR) and relative (%HRmax) heart rates—which were obtained in a time trial test (200-m) and an incremental intermittent test (Nx200-m) performed by swimmers with physical impairments. Methods: Eleven well-trained swimmers with physical impairments performed 200-m all-out and Nx200-m from low to all-out (controlled by a visual pacer), both with a respiratory valve system and a portable gas analyzer. Results: A paired Student’s t-test showed no statistical difference (p > .05) for all comparisons. The intraclass correlation coefficient (ICC) was 0.97 and 0.98 for in l/min and ml/kg/min, respectively; ICC = 0.75 to 0.9 for (l/min and ml/kg/min), (in l/min) and HR (beats/min); ICC = 0.5 and 0.75 for %HRmax; and ICC < 0.5 for RER. Passing-Bablok regression showed that the dispersions were acceptable, considering the proportionality, except for HR and %HRmax. Bland-Altman method showed a high level of agreement for all variables. Conclusions: The and , as well as the physiological variables and HR obtained, respectively, by 200-m and Nx200-m tests in swimmers with physical impairment were not different.

Analysis of relative age effect in muscular strength of adolescent swimmers

Purpose: The aim of this study is to analyse the effect of relative age in anthropometric measurements, muscular strength of adolescent swimmers. Material and Methods: The study sample was composed of 40 volunteers adolescent well-trained swimmers. Participants were grouped as swimmers born in the first quarter (January, February and March) and in the last quarter (October, November and December) of the same year. Anthropometric measurements were taken from each participant, and body mass index of participants were calculated. To determine performance parameters, handgrip, back and leg strength tests were performed on participants. The level of statistical significance was set at p &lt; .05. Results: Statistical analysis showed that there were statistically significant differences in the body height and BMI ( p &lt; .05 ), but body weight differences were not statistically significant between swimmers who are born first and last quarter of the same year ( p &gt; .05 ). There were significant differences in the means of absolute leg and handgrip strength between relative age groups. There were statistically significant differences in the means of relative back, leg and handgrip strength between groups ( p &lt; .05 ). All mean relative strength values of participants significantly differed in favour of the group born in the first quarter of the year. Conclusion: As a result of this study, it is determined that relative age has an effect on the measured anthropometric and muscular strength parameters of adolescent well-trained swimmers. The findings of this study revealed that relative age is an important factor to be considered in swimming performance in adolescent swimmers.

Human muscular mitochondrial fusion in athletes during exercise.

The main objective of this work was to investigate whether mitochondrial fusion occurs in the skeletal muscle of well-trained athletes in response to high-intensity exercise. Well-trained swimmers (n = 9) performed a duration-matched sprint interval training (SIT) and high-intensity high-volume training (HIHVT) session on separate days. Muscle samples from triceps brachii were taken before, immediately after, and 3 h after the training sessions. Transmission electron microscopy (TEM) was applied to assess mitochondrial morphology. Moreover, expression of genes coding for regulators of mitochondrial fusion and fission were assessed by real-time quantitative PCR. In addition, mitofusin (MFN)2 and optic atrophy 1 (OPA1) were quantified by Western blot analysis. TEM analyses showed that mitochondrial morphology remained altered for 3 h after HIHVT, whereas SIT-induced changes were only evident immediately after exercise. Only SIT increased MFN1 and MFN2 mRNA expression, whereas SIT and HIHVT both increased MFN2 protein content 3 h after exercise. Notably, only HIHVT increased OPA1 protein content. Mitochondrial morphologic changes that suggest fusion occurs in well-adapted athletes during exercise. However, HIHVT appears as a more robust inducer of mitochondrial fusion events than SIT. Indeed, SIT induces a rapid and transient change in mitochondrial morphology.-Huertas, J. R., Ruiz-Ojeda, F. J., Plaza-Díaz, J., Nordsborg, N. B., Martín-Albo, J., Rueda-Robles, A., Casuso, R. A. Human muscular mitochondrial fusion in athletes during exercise.

Digit ratio (2D:4D): relationship with freestyle swimming performance of adolescent well-trained swimmers

Purpose: The purpose of this study was to determine whether there was a relationship between the digit ratios and freestyle swimming performance of adolescent well-trained swimmers. Material and Methods: Twenty-two well-trained male swimmers who had at least 3 years of swim training experience were recruited as participants. The participants’ mean age was 14.1±1.5 years, body height was 164.5±11.3 cm, and body mass was 54.4±11.2 kg. Participants’ body height, mass, index finger (2D) and ring finger (4D) lengths were measured and digit ratio (2D:4D) and body mass index of participants was calculated. To determine the swimming performance of participants, the short (50m and 100m) and middle (200m and 400m) distance freestyle time-trial swimming tests were performed on participants. The association between the 2D:4D ratio and the swimming performance were determined by the Pearson correlation coefficient. Results. Our findings indicated that there were strong negative correlations (r &gt; .50) between the mean of BMI and swimming times of adolescent swimmers. ( p &gt; .05 ). However, result of this study revealed no relationship between the digit ratio (2D:4D) and swimming performance in adolescent swimmers. ( p &gt; .05 ). Conclusion. As a result, it may be stated that the 2D:4D ratio of swimmers is not a major parameter in predicting swimming performance for adolescent swimmers.

High-intensity high-volume swimming induces more robust signaling through PGC-1α and AMPK activation than sprint interval swimming in m. triceps brachii.

We aimed to test whether high-intensity high-volume training (HIHVT) swimming would induce more robust signaling than sprint interval training (SIT) swimming within the m. triceps brachii due to lower metabolic and oxidation. Nine well-trained swimmers performed the two training procedures on separate randomized days. Muscle biopsies from m. triceps brachii and blood samples were collected at three different time points: a) before the intervention (pre), b) immediately after the swimming procedures (post) and c) after 3 h of rest (3 h). Hydroperoxides, creatine kinase (CK), and lactate dehydrogenase (LDH) were quantified from blood samples, and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) and the AMPKpTHR172/AMPK ratio were quantified by Western blot analysis. PGC-1α, sirtuin 3 (SIRT3), superoxide-dismutase 2 (SOD2), and vascular endothelial growth factor (VEGF) mRNA levels were also quantified. SIT induced a higher release of LDH (p < 0.01 at all time points) and CK (p < 0.01 at post) than HIHVT, but neither SIT nor HIHVT altered systemic hydroperoxides. Additionally, neither SIRT3 nor SOD2 mRNA levels increased, while PGC-1α transcription increased at 3 h after SIT (p < 0.01) and after HIHVT (p < 0.001). However, PGC-1α protein was higher after HIHVT than after SIT (p < 0.05). Moreover, the AMPKpTHR172/AMPK ratio increased at post after SIT (p < 0.05), whereas this effect was delayed after HIHVT as it increased after 3 h (p < 0.05). In addition, VEGF transcription was higher in response to HIHVT (p < 0.05). In conclusion, SIT induces higher muscular stress than HIHVT without increasing systemic oxidation. In addition, HIHVT may induce more robust oxidative adaptations through PGC-1α and AMPK.

Intermittent hypoxic training improves anaerobic performance in competitive swimmers when implemented into a direct competition mesocycle.

The main objective of this research was to evaluate the efficacy of intermittent hypoxic training (IHT) on anaerobic and aerobic capacity and swimming performance in well-trained swimmers. Sixteen male swimmers were randomly divided into a hypoxia (H) group (n = 8), which trained in a normobaric hypoxia environment, and a control (C) group (n = 8), which exercised under normoxic conditions. However, one participant left the study without explanation. During the experiment group H trained on land twice per week in simulated hypoxia (FiO2 = 15.5%, corresponding to 2,500 m a.s.l); however, they conducted swim training in normoxic conditions. Group C performed the same training program under normoxic conditions. The training program included four weekly microcyles, followed by three days of recovery. During practice sessions on land, the swimmers performed 30 second sprints on an arm-ergometer, alternating with two minute high intensity intervals on a lower limb cycle ergometer. The results showed that the training on land caused a significant (p<0.05) increase in absolute maximal workload (WRmax) by 7.4% in group H and by 3.2% in group C and relative values of VO2max by 6.9% in group H and 3.7% in group C. However, absolute values of VO2max were not significantly changed. Additionally, a significant (p<0.05) increase in mean power (Pmean) during the first (11.7%) and second (11.9%) Wingate tests was only observed in group H. The delta values of lactate concentration (ΔLA) after both Wingate tests were significantly (p<0.05) higher in comparison to baseline levels by 28.8% in group H. Opposite changes were observed in delta values of blood pH (ΔpH) after both Wingate tests in group H, with a significant decrease in values of ΔpH by 33.3%. The IHT caused a significant (p<0.05) improvement in 100m and 200m swimming performance, by 2.1% and 1.8%, respectively in group H. Training in normoxia (group C), resulted in a significant (p<0.05) improvement of swimming performance at 100m and 200m, by 1.1% and 0.8%, respectively. In conclusion, the most important finding of this study includes a significant improvement in anaerobic capacity and swimming performance after high-intensity IHT. However, this training protocol had no effect on absolute values of VO2max and hematological variables.

VO2 at Maximal and Supramaximal Intensities: Lessons to High-Intensity Interval Training in Swimming.

To establish appropriate work intensity for interval training that would elicit maximal oxygen uptake (VO2max) for well-trained swimmers. Twelve male competitive swimmers completed an incremental protocol to determine the minimum velocity at VO2max (νVO2max) and, in randomized order, 3 square-wave exercises from rest to 95%, 100%, and 105% of νVO2max. Temporal aspects of the VO2 response were examined in these latter. Swimming at 105% of νVO2max took less (P < .04) absolute time to achieve 90%, 95%, and 100% of VO2max intensities (35.0 ± 7.7, 58.3 ± 15.9, 58.3 ± 19.3 s) compared with 95% (72.1 ± 34.3, 106.7 ± 43.9, 151.1 ± 52.4 s) and 100% (55.8 ± 24.5, 84.2 ± 35.4, 95.6 ± 29.8 s) of VO2max. However, swimming at 95% of νVO2max resulted in longer absolute time (P < .001) at or above the desired intensities (90%: 268.3 ± 72.5 s; 95%: 233.8 ± 74.3 s; 100%: 173.6 ± 78.2 s) and more relative time at or above 95% of VO2max than 105% of νVO2max (68.6% ± 13.5% vs 55.3% ± 11.5%, P < .03), and at or above 100% of VO2max than 100% and 105% of νVO2max (52.7% ± 16.3% vs 28.2% ± 10.5% and 34.0% ± 11.3%, P < .001). At 60 s of effort, swimmers achieved 85.8% ± 11.2%, 88.3% ± 5.9%, and 94.7% ± 5.5% of the VO2max when swimming at 95%, 100%, and 105% of νVO2max, respectively. When training to elicit VO2max, using higher swimming intensities will promote a faster VO2 response but a shorter time spent above these intensities. However, lower intensities allow maintaining the desired response for a longer period of time. Moreover, using the 60-s time period seem to be a more adequate stimulus than shorter ones (~30-s), especially when performed at 105% of νVO2max intensity.

Does Swimming at a Moderate Altitude Favor a Lower Oxidative Stress in an Intensity-Dependent Manner? Role of Nonenzymatic Antioxidants.

Casuso, Rafael A., Jerónimo Aragón-Vela, Gracia López-Contreras, Silvana N. Gomes, Cristina Casals, Yaira Barranco-Ruiz, Jordi J. Mercadé, and Jesus R. Huertas. Does swimming at a moderate altitude favor a lower oxidative stress in an intensity-dependent manner? Role of nonenzymatic antioxidants. High-Alt Med Biol. 18:46-55, 2017.-we aimed to describe oxidative damage and enzymatic and nonenzymatic antioxidant responses to swimming at different intensities in hypoxia. We recruited 12 highly experienced swimmers who have been involved in competitive swimming for at least 9 years. They performed a total of six swimming sessions carried out at low (LOW), moderate (MOD), or high (HIGH) intensity at low altitude (630 m) and at 2320 m above sea level. Blood samples were collected before the session (Pre), after the cool down (Post), and after 15 minutes of recovery (Rec). Blood lactate (BL) and heart rate were recorded throughout the main part of the session. Average velocities did not change between hypoxia and normoxia. We found a higher BL in response to MOD intensity in hypoxia. Plasmatic hydroperoxide level decreased at all intensities when swimming in hypoxia. This effect coincided with a lower glutation peroxidase activity and a marked mobilization of the circulating levels of α-tocopherol and coenzyme Q10 in an intensity-dependent manner. Our results suggest that, regardless of the intensity, no oxidative damage is found in response to hypoxic swimming in well-trained swimmers. Indeed, swimmers show a highly efficient antioxidant system by stimulating the mobilization of nonenzymatic antioxidants.

Desempenho em 200 m nado crawl: índice de coordenação, tempo propulsivo e cinemática de nado

DOI: http://dx.doi.org/10.5007/1980-0037.2016v18n3p311 The aim of this study was to compare coordination index, propulsive time, duration of stroke phases and kinematic parameters over 200 m front crawl. Variables were compared among four sections of 50 m (T1 to T4) in fifteen competitive swimmers (age: 21.1 ± 7.1 years; height: 180.1 ± 6.1 cm; height: 187.3 ± 8, 1 cm; body mass: 72.1 ± 10.1 kg; better performance in the race: 77.5 ± 4.7% of the world record). Data were obtained with two video cameras (60 Hz - coupled to a cart on rails on the side of the pool) for simultaneous images of the swimmer’s sagittal plan: below the water line and above the water line. Mean stroke rate stroke length, assumed as the mean distance traveled per cycle, and mean swimming speed were obtained with manual timing. Over the 200 m, the coordination index remained unchanged (p &gt;0.05), but there was an increase in the frequency of cycles (p &lt;0.05) and reduction of distance traveled per cycle (p &lt;0.05). Between T1 and T2, there was an increase in the propulsive time (p &lt;0.05) and between T1 and T4, there was an increase in the length of the pull phase (p &lt;0.05). The swimming speed decreased only between T1 and T2 (p &lt;0.05). Over 200 m front crawl, well-trained swimmers increment propulsive time and pull phase duration and frequency of stroke cycles, and such changes may be due to the speed maintenance attempt over the 200 m.

Effect of BDKRB2 Gene -9/+9 Polymorphism on Training Improvements in Competitive Swimmers.

The aim of the study was to investigate the possible association between the BDKRB2 gene and training-induced improvements in swimming performance in well-trained swimmers. One hundred Polish swimmers (52 men and 48 women, aged 18.1 ± 1.9 years), who competed in national and international competitions at middle- (200 m) and long-distance events (≥400 m), were included in the study. Athletes' genotype and allele distributions were analyzed in comparison to 230 unrelated sedentary subjects, who served as controls, with the χ test. All samples were genotyped for the BDKRB2 -9/+9 polymorphism by polymerase chain reaction. The effects of genotype on swimming performance improvements were analyzed with two-way (3 × 2; genotype × time) analysis of variance with metric age as a covariate. The training period of 1.9 ± 0.4 years had a significant (p < 0.01) effect on swimming performance, both in female and male athletes. Both in female and male athletes, the BDKRB2 gene -9/+9 polymorphism had no significant effect on swimming performance. An interaction effect of BDKRB2 gene -9/+9 polymorphism × time was found for swimming performance only in male athletes. Post hoc analyses showed that swimmers with the +9/+9 BDKRB2 genotype had a greater improvement in swimming performance than swimmers with the -9/+9 polymorphism (p ≤ 0.05). No interaction effects for gender × BDKRB2 gene -9/+9 polymorphism were found for either swimming performance or improvement in swimming performance. These results suggest that the response to long-term exercise training could be modulated by the BDKRB2 gene -9/+9 polymorphism in male athletes. In well-trained swimmers, BDKRB2 gene variation was not found to be an independent determinant of swimming performance.

Response of Critical Speed to Different Macrocycle Phases during Linear Periodization on Young Swimmers

Sport training programs to young swimmers have to aggregate different physical stimulus to collaborate with overall physical development, which can lead to reach best results in competitions. Linear periodization seems to be a powerful tool that allow the organization of these stimulus. However, this model has been not studied. Regarding physical capacities, aerobic fitness is inversely related with fatigue and exercise performance. Although aerobic capacity evaluation used to be expensive, critical speed (CS) is easy and non-expensive tool capable to make this measurement.Thus, the aim of this study was evaluate the effects of linear periodization in CS on well-trained young swimmers. Sixteen athletes (age: 14.06 1.22 years, height: 163.5210.99 cm, weight: 57.412.7 kg, body mass index: 21.2437; 7 ♀), were underwent to a linear macrocycle training with 23 weeks divided in four mesocycles: general endurance (i.e., 4 weeks), specific endurance (i.e., 8 weeks), competitive (i.e., 7 weeks) and taper (i.e., 4 weeks). Results showed significantly improve on CS after competitive and taper mesocycle phases, which was composed by higher training intensity in comparison with other macrocycle phases. Therefore, the results of the present study indicate a collaboration of mesocycle intensity on the cumulative effects of linear periodization in CS improve on young swimmers.

Pacing accuracy during an incremental step test in adolescent swimmers

To assess pacing accuracy in a group of adolescent swimmers during an incremental step test. Fifteen well-trained swimmers (age 15±1.5 years; height 170.2±8.8 cm; mass 60.2±6.6 kg), completed two 7×200 m tests, separated by ~72 hours. They swam to a predetermined incrementally increasing pace per step and were instructed to swim at even pace. Upon completion of each step, rating of perceived exertion, heart rate and blood lactate were recorded. Significant differences observed for both trials between actual and predicted swim time (P<0.05). Significant differences also observed between the first and second 100 m of each step in trial 1 for step 1 (P=0.001, effect size [ES] =0.54), step 2 (P=0.0001, ES =0.57), step 4 (P=0.0001, ES =0.53), step 5 (P=0.005, ES =0.65), step 6 (P=0.0001, ES =0.50), and step 7 (P=0.0001, ES =0.70). Similar responses witnessed for trial 2 (P<0.05). Findings suggest that the finite anaerobic capacity was engaged sooner than would normally be anticipated, as a function of an inability to regulate pace. This is proposed to be a consequence of the volume of exposure to the biological and psychological sensations and cognitive developmental status. Given the apparent error in pacing judgment exhibited in this population group, caution should be applied when adopting such tests to monitor training responses with adolescent athletes, and alternate means of modulating pace be investigated.