Breathing frequency along the 400 m free style: association with pratice
The aims of the present study were: i) to assess ventilator and metabolic variables during a 400m crawl event; ii) to assess the relative contribution of aerobic and anaerobic energy during the event; iii) to investigate the associations between the performance and ventilator and metabolic variables. The sample comprised 8 male Portuguese swimmers with a mean age of 17.7±2.3 years, regularly involved in competitive swimming. Each subject performed a submaximal and a supramaximal swimming tests with a 48h recovery between them. The tests were conducted in an indoor 25m swimming pool. During both tests gas analysis was performed and VO2 was recorded in 20 s intervals. The submaximal test comprised 5 bouts of 400m with individual recovery between them. Initial speed was 3 to 4m.s-1 ans speed increases were 0.5m.s-1. Swimming speed was kept constant with a light pacer placed in the bottom of the pool. Blood samples were collected after each bout. The supramaximal test was an all-out 400m crawl swimming. Blood samples were collected every 2 min after the test until blood lactate levelled-off. NO significant association was found between the assessed variables and the performance. However, we found a significant association of the performance with anthopometric measures, namely total body fat (r=0.78; p²0.05). We also found that to swimming speeds up to Å1.3 m.s-1, the aerobic energy sources provided the major fraction of energy release. Moreover, the swimmers that presented the largest accumulated oxygen deficit presented the also the larger mean values of the swimming speed associated with the lactic threshold.
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