The effects of sodium hydrogen carbonate ingestion during the recovery period between two 200-m front-crawl time trials.

PURPOSE: The aim of this study was to determine how sodium hydrogen carbonate (NaHCO3) ingestion during a 1-h recovery period after a 200-m front-crawl swim affects blood-gas levels, acid-base balance, and performance during a successive trial. METHODS: Fourteen national-level male swimmers (age: 21 ± 3 years, body mass (BM):77 ± 10 kg, stature: 181 ± 7 cm) performed four maximal 200-m front-crawl tests. On one of the two days, the swimmers swam two 200-m tests with a 1-h recovery break, during which they drank water (WATER); on the other day, they performed the same protocol but consumed 0.3 g min-1 NaHCO3 solution during the recovery break (NaHCO3). RESULTS: The ingestion of NaHCO3 before the second test had no effect on swim time despite a greater [ HCO 3 - ] (19.2 ± 2.3 mmol L-1) than that measured during the first test (NaHCO3) (14.5 ± 1.1 mmol L-1) and the other two tests (WATER) (12.7 ± 2.4 and 14.8 ± 1.5 mmol L-1; F = 18.554; p = 0.000) and a higher blood pH (7.46 ± 0.03) than that measured during the first test (NaHCO3) (7.39 ± 0.02) and the other two tests (WATER) (7.16 ± 0.04 and 7.20 ± 0.05); (F = 5.255; p = 0.004). An increase in blood pCO2 (0.2 ± 0.3 kPa) between both tests (NaHCO3) compared to unchanged pCO2 values (- 0.1 ± 0.3 kPa) between the other two tests (WATER) (t = - 2.984; p = 0.011; power = 0.741) was confirmed. CONCLUSIONS: NaHCO3 ingestion during the recovery period between two 200-m front-crawl time trials had a strong buffering effect that did not positively affect performance. An increase in pCO2 may have counterbalanced this impact.

Effects of Moderate Altitude Training Combined with Moderate or High-altitude Residence.

We aimed to identify potential physiological and performance differences of trained cross-country skiers (V˙o2max=60±4 ml ∙ kg-1 ∙ min-1) following two, 3-week long altitude modalities: 1) training at moderate altitudes (600-1700 m) and living at 1500 m (LMTM;N=8); and 2) training at moderate altitudes (600-1700 m) and living at 1500 m with additional nocturnal normobaric hypoxic exposures (FiO2 =0.17;LHTM; N=8). All participants conducted the same training throughout the altitude training phase and underwent maximal roller ski trials and submaximal cyclo-ergometery before, during and one week after the training camps. No exercise performance or hematological differences were observed between the two modalities. The average roller ski velocities were increased one week after the training camps following both LMTM (p=0.03) and LHTM (p=0.04) with no difference between the two (p=0.68). During the submaximal test, LMTM increased the Tissue Oxygenation Index (11.5±6.5 to 1.0±8.5%; p=0.04), decreased the total hemoglobin concentration (15.1±6.5 to 1.7±12.9 a.u.;p=0.02), and increased blood pH (7.36±0.03 to 7.39±0.03;p=0.03). On the other hand, LHTM augmented minute ventilation (76±14 to 88±10 l·min-1;p=0.04) and systemic blood oxygen saturation by 2±1%; (p=0.02) with no such differences observed following the LMTM. Collectively, despite minor physiological differences observed between the two tested altitude training modalities both induced comparable exercise performance modulation.

Neuromuscular Adaptations in Elite Swimmers During Concurrent Strength and Endurance Training at Low and Moderate Altitudes.

ABSTRACT: Tomazin, K, Strojnik, V, Feriche, B, Garcia Ramos, A, Strumbelj, B, and Stirn, I. Neuromuscular adaptations in elite swimmers during concurrent strength and endurance training at low and moderate altitudes. J Strength Cond Res 36(4): 1111-1119, 2022-This study evaluated neuromuscular adaptations in elite swimmers during concurrent strength and endurance training (SET) at low (295 m) and moderate (2,320 m) altitudes. Sixteen elite swimmers took part in a 3-week SET during a general preparation phase. All neuromuscular tests were performed a week before and after a SET. In posttraining, maximal knee isometric torque (TMVC) and soleus H-reflex remained statistically unchanged for sea-level (SL) and for altitude (AL) training. Rate of torque development (RTD) decreased post-SL (-14.5%; p < 0.01) but not post-AL (-4.7%; p > 0.05) training. Vastus lateralis electromyographic (EMG) activity during RTD decreased post-SL (-17.0%; P = 0.05) but not post-AL (4.8%; p > 0.05) training. Quadriceps twitch torque (TTW) significantly increased post-AL (12.1%; p < 0.01) but not post-SL (-1.0%; p > 0.05; training × altitude: F1,15 = 12.4; p < 0.01) training. Quadriceps twitch contraction time and M-wave amplitude remained statistically unchanged post-SL and post-AL training. After SL training, increment in TMVC was accompanied with increment in vastus lateralis EMG (R = 0.76; p < 0.01) and TTW (R = 0.48; p < 0.06). Posttraining in AL, increment in TMVC was accompanied with increment in TTW (R = 0.54; p < 0.05). Strength and endurance training at altitude seems to prompt adaptations in twitch contractile properties. In contrast, SET performed at SL may hamper the magnitude of neural adaptations to strength training, particularly during rapid voluntary contractions. In conclusion, SET at AL might benefit muscular adaptations in swimmers compared with training at SL.

Dual Career Development Perspective: Factors Affecting Quality of Post-sport Career Transition of Employed Olympic Athletes.

Although Olympic athletes are celebrated for their sports achievements, they often face serious difficulties in their post-sport career employment. Factors of development that are affecting the quality of post-sport career transition of Olympic athletes are important to acknowledge in the dual career (DC) development perspective. Due to the side lining of academic activities, athletes are often not well prepared for the labor market. If they do not gain sufficient financial background in their careers, it can lead to a lack of proper economic inclusion of athletes in their post-sport career employment and further impact their lives. Career transitions of athletes have been the subject of research in different aspects of DC support (e.g., athletic, psychological, psychosocial, academic/vocational, financial), but most research is linked to the student-athlete DC perspective. Therefore, the aim of our research was to examine the impact of factors directly contributing to the quality of the post-sport career transition in Slovenian elite and Olympic athletes and the social class position and employment of these athletes after the termination of their sports career. From DC support practice, we learned that although athletes often have a proper level of education, their post-sport career transitions were not successful. To fill this gap, 168 elite athletes (Mage = 33.34, SD = 13.1) from Slovenia were asked to complete online questionnaires. The results showed a significant contribution of education and DC support-related finances (e.g., employment of athletes in public administration) to the quality of post-sport career transition. Regarding developing a national DC model and based on empirical research, this study identifies the social class position and employment status of former elite athletes from Slovenia. It also identifies opportunities for further research on the quality of the post-sport career transitions and perspectives on DC support. Understanding how different factors contribute to the integrated development of individual athletes to reach their potential in sports, education, and their post-sport career employment is important for theorists, DC practitioners, and stakeholders working with DC athletes. To develop a sufficient mechanism, DC support providers should consider supporting education along with the financial support of athletes during their sports careers and recognizing study-training ecosystems, based on good practices to successfully transition to their post-sport careers. These findings can also be useful for athletes and their athletic triangle support network (e.g., coaches and parents) as a support in the decision-making.

The Effect of an Altitude Training Camp on Swimming Start Time and Loaded Squat Jump Performance.

This study evaluated the influence of an altitude training (AT) camp on swimming start time and loaded squat jump performance. To accomplish this goal, 13 international swimmers (8 women, 5 men) were allocated to both the control (Sea Level Training, SLT) and experimental conditions (AT, 2320 m above sea level) that were separated by a one year period. All tests (15 m freestyle swimming start and loaded squat jumps with additional loads of 25%, 50%, 75%, and 100% of swimmers' body weight) were performed before and after a concurrent 3-week strength and endurance training program prescribed by the national coach. Following the SLT camp, significant impairments in swimming start times to 10 (+3.1%) and 15 m (+4.0%) were observed (P < 0.05), whereas no significant changes for the same distances were detected following the AT camp (-0.89%; P > 0.05). Trivial changes in peak velocity were obtained during the loaded squat jump after both training periods (effect sizes: < 0.20). Based on these results we can conclude that a traditional training high-living high strategy concurrent training of 3 weeks does not adversely affect swimming start time and loaded squat jump performance in high level swimmers, but further studies are necessary to assess the effectiveness of power-oriented resistance training in the development of explosive actions.

The Relationship Between the Lower-Body Muscular Profile and Swimming Start Performance.

This study aimed to examine the correlation of different dry land strength and power tests with swimming start performance. Twenty international level female swimmers (age 15.3 ± 1.6 years, FINA point score 709.6 ± 71.1) performed the track freestyle start. Additionally, dry land tests were conducted: a) squat (SJ) and countermovement jumps (CMJ), b) squat jumps with additional resistance equivalent to 25, 50, 75 and 100% of swimmers' body weight [BW]), and c) leg extension and leg flexion maximal voluntary isometric contractions. Correlations between dry land tests and start times at 5, 10 and 15 m were quantified through Pearson's linear correlation coefficients (r). The peak bar velocity reached during the jumps with additional resistance was the variable most correlated to swimming start performance (r = -0.57 to -0.66 at 25%BW; r = -0.57 to -0.72 at 50%BW; r = -0.59 to -0.68 at 75%BW; r = -0.50 to - 0.64 at 100%BW). A few significant correlations between the parameters of the SJ and the CMJ with times of 5 and 10 m were found, and none with the isometric variables. The peak velocity reached during jumps with external loads relative to BW was found a good indicator of swimming start performance.

Relationship between different push-off variables and start performance in experienced swimmers.

The objective of this study was to determine the relationship between different variables measured with a force plate during the swimming start push-off phase and start performance presented by times to 5, 10 and 15 m. Twenty-one women from the Slovenian national swimming team performed two different swim starts (freestyle and undulatory) on a portable force plate to a distance further than 15 m. Correlations between push-off variables and times to 5, 10 and 15 m were quantified through Pearson's product-moment correlation coefficient (r). The variables that significantly correlated (p < .05) to all times measured in the two starts performed were: average horizontal acceleration (freestyle: r = -0.58 to -0.71; and undulatory: r = -0.55 to -0.66), horizontal take-off velocity (freestyle: r = -0.56 to -0.69; and undulatory: r = -0.53 to -0.67) and resultant take-off velocity (freestyle: r = -0.53 to -0.65; and undulatory: r = -0.52 to -0.61). None of the variables derived from the vertical force were correlated to swimming start performance (p > .05). Based on the results of this study, we can conclude that horizontal take-off velocity and average horizontal acceleration (calculated as the average horizontal force divided by swimmer's body mass) are the variables most related to swimming start performance in experienced swimmers, and therefore could be the preferred measures to monitor swimmers' efficiency during the push-off phase.

Graded shuttle run performance by playing positions in elite female basketball.

A graded shuttle run test was used to assess differences in physiological parameters between playing positions in elite female basketball players. Twenty-four female basketball players (8 guards, 8 forwards, and 8 centers) who played for the senior national teams of Slovenia and Serbia were tested with the 30-15 intermittent fitness test. During the shuttle run, the following physiological parameters were measured: oxygen consumption ((Equation is included in full-text article.)), carbon dioxide production ((Equation is included in full-text article.)), pulmonary ventilation (VE) breath by breath, respiratory quotient, oxygen pulse as the (Equation is included in full-text article.)vs. HR ratio and [LA]. No significant differences were found for any of the measures between the 3 playing positions. Although this finding was surprising, future studies should try to determine whether the tactics used in female basketball determine that the interpositional differences seen in male basketball are not evident.

The difference in respiratory and blood gas values during recovery after exercise with spontaneous versus reduced breathing frequency.

Extrapolation from post-exercise measurements has been used to estimate respiratory and blood gas parameters during exercise. This may not be accurate in exercise with reduced breathing frequency (RBF), since spontaneous breathing usually follows exercise. This study was performed to ascertain whether measurement of oxygen saturation and blood gases immediately after exercise accurately reflected their values during exercise with RBF. Eight healthy male subjects performed an incremental cycling test with RBF at 10 breaths per minute. A constant load test with RBF (B10) was then performed to exhaustion at the peak power output obtained during the incremental test. Finally, the subjects repeated the constant load test with spontaneous breathing (SB) using the same protocol as B10. Pulmonary ventilation (VE), end-tidal oxygen (PETO2), and carbon dioxide pressures (PETCO2) and oxygen saturation (SaO2) were measured during both constant load tests. The partial pressures of oxygen (PO2) and carbon dioxide (PCO2) in capillary blood were measured during the last minute of exercise, immediately following exercise and during the third minute of recovery. At the end of exercise RBF resulted in lower PETO2, SaO2 and PO2, and higher PETCO2 and PCO2 when compared to spontaneous breathing during exercise. Lower SaO2 and PETO2 were detected only for the first 16s and 20s of recovery after B10 compared to the corresponding period in SB. There were no significant differences in PO2 between SB and B10 measured immediately after the exercise. During recovery from exercise, PETCO2 remained elevated for the first 120s in the B10 trial. There were also significant differences between SB and B10 in PCO2 immediately after exercise. We conclude that RBF during high intensity exercise results in hypoxia; however, due to post-exercise hyperpnoea, measurements of blood gas parameters taken 15s after cessation of exercise did not reflect the changes in PO2 and SaO2 seen during exercise. Key pointsIn some sports, the environment is inappropriate for direct measurement of respiratory and blood gas parameters during exercise. To overcome this problem, extrapolation from post-exercise measurements has often been used to estimate changes in respiratory and blood gas parameters during exercise.The possibility of hypoxia and hypercapnia during exercise with reduced breathing frequency has been tested by measuring capillary blood sampled after the exercise.Reduced breathing frequency during high intensity exercise results in hypoxia; however, due to marked post-exercise hyperventilation, measurements of blood gas parameters taken 15 s after the cessation of exercise did not yield any changes in these parameters.Despite hyperventilation during recovery, hypercapnia could be detected by measuring blood gas parameters within 15 s after the exercise with reduced breathing frequency.

Can Blood Gas and Acid-Base Parameters at Maximal 200 Meters Front Crawl Swimming be Different Between Former Competitive and Recreational Swimmers?

The aim of the present study was to ascertain whether maximal 200 m front crawl swimming strategies and breathing patterns influenced blood gas and acid-base parameters in a manner which gives advantage to former competitive swimmers in comparison with their recreational colleagues. Twelve former competitive male swimmers (the CS group) and nine recreational male swimmers (the RS group) performed a maximal 200 m front crawl swimming with self- selected breathing pattern. Stroke rate (SR) and breathing frequency (BF) were measured during the swimming test. Measures also included blood lactate concentration ([LA]) and parameters of blood acid-base status before and during the first minute after the swimming test. The CS group swam faster then the RS group. Both groups have similar and steady SR throughout the swimming test. This was not matched by similar BF in the CS group but matched it very well in the RS group (r = 0.89). At the beginning of swimming test the CS group had low BF, but they increased it throughout the swimming test. The BF at the RS group remained constant with only mirror variations throughout the swimming test. Such difference in velocity and breathing resulted in maintaining of blood Po2 from hypoxia and Pco2 from hypercapnia. This was similar in both groups. [LA] increased faster in the CS group than in the RS group. On the contrary, the rate of pH decrease remained similar in both groups. The former competitive swimmers showed three possible advantages in comparison to recreational swimmers during maximal 200 m front crawl swimming: a more dynamic and precise regulation of breathing, more powerful bicarbonate buffering system and better synchronization between breathing needs and breathing response during swimming. Key pointsTraining programs for competitive swimmers should promote adaptations to maximal efforts.Those adaptations should include high and maximal intensity swims with controlled breathing frequency (taking breath every fourth, fifth, sixth or eighth stroke cycle for front crawl swimming).Such training will improve breathing regulation in order to impose a better synchronization between breathing needs and breathing response during maximal swimming.