Effects of an experimental taper period on male and female swimmers.

BACKGROUND: This study investigated the possible influence of the gender on the responses of swimmers during a taper period (TP). METHODS: Ten males (19±3 years and 73.5±7.8 kg) and ten females (17±2 years and 54.7±7.2 kg) swimmers were submitted to a 12-week training, followed by three weeks of the TP. Before and after the TP we evaluated the performance at 100 m freestyle, stroke parameters and lactacidemic responses; lactate minimum intensity (LMI) and stroke parameters associated with LMI and the propulsive force in tethered swimming. TP consisted of 14 sessions with mean volume 2253±1213 m/session at an intensity below than the LMI, 1730±327 m/session at an intensity near the LMI and 1530±1019 m/session at an intensity above the LMI. RESULTS: Significant effects of the genders were observed for LMI and stroke parameters (P<0.001 and η2>0.52 [large]) and propulsive force (P=0.001; η2=0.59 [large]). However, no significant effects of the TP were identified in the performance of the 100 m freestyle (P=0.66; η2=0.006 [small]), propulsive force (P>0.63; η2<0.006 [small]), aerobic parameters (LMI: P=0.32 and η2=0.03 [small]) and mechanical parameters (P>0.23; η2=0.01 [small]). Nonetheless, the peak blood lactate concentrations were improved after TP (P=0.014; η2=0.16 [large]), without significant interactions (P=0.38; η2=0.02 [small]), as well as the mechanical parameters during maximum 100 m freestyle (P<0.04 and η2>0.10 [medium]). CONCLUSIONS: Hence, men and women presenting significantly different values in the age group studied, the responses observed after the TP investigated were the same independent of gender.

Backward extrapolation technique: analysis of different criteria after supramaximal exercise in cycling.

BACKGROUND: Backward extrapolation technique (BE) was used to estimate V̇O2 from postexercise measuring, eliminating oronasal mask (OM) during the efforts. Despite its advantage, literature presents discrepancy in applied methods. Thus, the first aim of this study was to compare different mathematical criteria to estimate values of V̇O2 during a supramaximal effort (V̇O2PEAK), while the second aim was to verify the effects of OM on cycling performance. METHODS: Twenty-four male cyclists (35±6 years, 81.3±8.9 kg, 180±6 cm) performed three days of tests, with at least 24 h of interval between each test. Firstly, a graded exercise test was applied to determine V̇O2max and your correspondent intensity (MAP). The second and the third day were destined to supramaximal efforts at 120% of MAP, performed with (Supramask) and without (Suprabe) oronasal mask (OM) in a randomized order. After Suprabe, OM was coupled, and BE was applied. Sixty-six values of V̇O2 were obtained based on a linear regression fitting. RESULTS: V̇O2peak can be estimated using different curve lengths. However, only curves between 20 and 60 s with extrapolation to 3 s or lesser shows at least one consistent criterion. The 60 s curve extrapoled to -3 s was the most accurate criteria (P=0.723; ES=-0.055; r=0.824; Bias=-0.36 and LoA=7.72 mL.kg.min-1). Performance was not impaired with OM and was similar in both condition (P=0.84, ES=0.04). CONCLUSIONS: We conclude that it was possible to accurately estimate V̇O2 values of a supramaximal effort without any respiratory apparatus with a time-efficient analysis. Therefore, we recommended the use of a 60 seconds V̇O2 curve analysis with a negative extrapolation for 3 seconds.

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 120 min 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 5 min post the effort for taurine and glycerol analysis. Immediately before and 3, 5, and 7 min post the effort, blood samples from the earlobe were collected to determine lactate levels. An increase of 159% was observed in taurine plasma levels 120 min 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 ± 2.78 mmol L-1; PLA: 11.52 ± 2.19 mmol L-1, p = 0.04). Acute taurine supplementation 120 min 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.

Effects of taurine on markers of muscle damage, inflammatory response and physical performance in triathletes.

BACKGROUND: The practice of prolonged exercise with high intensity, as seen in triathlon training, can cause physiological imbalances that might result in muscle fatigue, muscle damage and changes in systemic inflammatory response, thus reduce the athletes' physical performance, therefore, both adequate total caloric and macronutrient intake also the use of a specific ergogenic aid, as taurine supplementation would be an alternative to prevent inflammation and muscle damage. In order to verify the effects of 8 weeks of taurine and chocolate milk supplementation, markers of muscle damage, inflammation, and aerobic capacity were quantified in triathletes. METHODS: A double-blind, crossover, randomized study was conducted with 9 male long-distance triathletes, aged 25-35 years. Supplementation of 3 g of taurine (TAU) or placebo (PLA) associated with 400 mL low fat chocolate milk was performed during an 8-week period. In order to verify the effects of the supplementation protocol markers of muscle damage as lactate dehydrogenase (LDH) and creatine kinase (CK), and inflammatory markers tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were quantified, also triathletes' performance was evaluated by exhaust test on a treadmill. RESULTS: It was observed a significant increase in taurine and CK plasma levels after TAU supplementation (P=0.02 and P=0.01, respectively). However, LDH concentrations did not differ significantly after the supplementations performed, and there were no changes in physical performance parameters; anaerobic threshold, perceived exertion, heart rate, and the concentrations of IL-6 and TNF-α. CONCLUSIONS: Taurine supplementation did not provide benefits on performance and muscle damage in triathletes.

Anaerobic Contribution Determined in Swimming Distances: Relation with Performance.

Total anaerobic contribution (TAn) can be assessed by accumulated oxygen deficit, and through sum of glycolytic and phosphagen contribution which enable the evaluation of TAn without influences on mechanical parameters. However, little is known about the difference of TAn within swimming distances. Therefore, the objectives of the present study were to determine and compare the TAn in different performances using the backward extrapolation technique and amount of lactate accumulated during exercise, and relate it with swimming performance. Fourteen competitive swimmers performed five maximal front crawl swims of 50, 100, 200, 400, and 800 m. The total phosphagen (AnAl) and glycolytic (AnLa) contributions were assumed as the fast component of post-exercise oxygen consumption (EPOCFAST) and amount of blood lactate accumulated during exercise, respectively. TAn was the sum of AnAl and AnLa. Significantly lower values of AnLa were observed in the 800 m (p < 0.01) than other distances. For AnAl, the 50 m performance presented the lowest values, followed by 100 and 800 m (p < 0.01). The highest values of AnAl were observed in the 200 and 400 m (p > 0.13). The TAn was significantly higher in the 200 and 400 m performances than observed at 50 and 800 m (p < 0.01). Anaerobic contributions were correlated with 50, 100, 200, and 400 m performances (p < 0.01). The AnAl contribution was not correlated with 400 m performance. Anaerobic parameters were not correlated with 800 m performance. In conclusion, the highest values of anaerobic contribution were observed in the 200 and 400 m distances. Moreover, TAn is important to performances below 400 m, and may be used in training routines.