Oxygen uptake.

<p>Maximal oxygen uptake (VO_2max) determined during freestyle swimming in a swimming flume with increasing water speed until exhaustion in two groups of swimmers before (PRE) and after (POST) a training intervention. One group performed usual swim-training (CON) and another group reduced their training volume by 50% and more than doubled the amount of high-intensity training (HIT). On average, VO_2max was similar before and after the 12 week intervention period in both groups. Individual data is presented. Open circles: male; Closed circles: female.