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; PLA: 11.52 ± 2.19 mmol L, 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.

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.

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Background: In the dynamic knee extension (DKE), a metal bar is positioned parallel to bicycle frame, replacing the pedal of a cycle ergometer, which allow consecutives extensions instead of pedaling movement. Considering the fixed ratchet of cycle ergometer, the knee joint returns to its initial position passively, isolating the quadriceps group during the exercise. Thus, DKE can be used to investigate the role of the anterior thigh muscles for the locomotion or balance, for example. However, the DKE ergometer is not commercially available. Aim: to describe the construction of a prototype ergometer for DKE and characterize the force signal and electromyography responses. Methods: Six participants underwent a progressive effort to exhaustion. The electromyography signal of Vastus Lateralis and Biceps Femoris were monitored. The last 10 extensions of each stage were used for analyzes. Results: the force signal has three phases: I: knee extension moment; II: crank draws the metal rod back; III: rapid compression of the load cell by the leg. In addition, Vastus Lateralis activation was higher than Biceps Femoris in all stages (p<0.02). Interpretation: These results demonstrated that is possible to construct an ergometer for DKE, which increase the possibilities of research in motor behavior.