Keywords: physiology, oxygen uptake, blood metabolites, ammonia and lactate concentration

Ten moderately trained male swimmers volunteered to take part in a recent study. They were divided into two groups:
1. five swimmers swam the front crawl stroke (crawl stroke group)
2. five swam the breaststroke (breaststroke group)

All subjects swam wearing conventional swimsuits, typically used by competitive swimmers (swimsuit); they also wore training shirts, pants, and shoes (training clothes).

Both groups would swim as fast as they could for 60 seconds, first wearing training clothes and then wearing swimsuits.

During each swimming period the measurements taken were:

1. swimming speed
2. stroke rates
3. distance covered per stroke
4. heart rate
5. oxygen intake

Peak ammonia and lactate concentrations in the blood were measured after each swimming exercise, wearing a swimsuit and training clothes.

This study demonstrated that the average speed decreased considerably when the subjects wore training clothes compared to wearing swimsuits in both the crawl stroke and breaststroke groups.

Speed

The average swimming speed wearing training clothes decreased much more in the crawl stroke than in the breaststroke in comparison with wearing swimsuits.

Stroke Rates

The stroke rates of swimmers wearing training clothes were lower than those wearing swimsuits in the crawl stroke, however, there was no significant stroke difference found in the breaststroke.

Distance

The distance covered per stroke of those wearing training clothes was shorter than those wearing swimsuits in the crawl stroke and the breaststroke.

Heart Rate & Oxygen Uptake

Both the heart rate and the oxygen uptake during the swimming exercise were not significantly different between those subjects wearing training clothes and swimsuits in the crawl stroke and in the breaststroke.

Ammonia & Lactate

The peak blood ammonia and lactate concentrations after swimming with swimsuits were significantly higher than with training clothes in the crawl stroke. However, there were no significant differences in the blood ammonia and lactate concentrations between swimmers wearing training clothes and swimsuits in the breaststroke.

Findings

These findings demonstrated that the decrease of the average speed in the crawl stroke wearing training clothes might be due to the decrease in the stroke rate and distance per stroke. It could also be explained by the decrease of glycogen break down and the purine nucleotide degradation.