Lactate kinetics after intermittent and continuous exercise training

The purpose of this study was to assess, the effects of continuous and intermittent exercise training on lactate kinetic parameters and maximal aerobic speed (MAS) using field tests. Twenty-four male sport students were equally divided into continuous (CT) and intermittent (IT) physically trained groups. Another six participants acted as non-trained controls (CG). The trained participants practiced 6-days per week for 6 weeks. Before and after training, all participants completed an incremental exercise test to assess their MAS, and a 30-second supramaximal exercise followed by 30 minutes of active recovery to determine the individual blood lactate recovery curve. It was found that exercise training has significantly increased MAS (p < 0.001), the lactate exchange and removal abilities as well as the lactate concentrations at the beginning of the recovery ([La](0)); for both CT and IT groups; this was accompanied by a significant reduction of the time to lactate-peak. Nevertheless, the improvement in MAS was significantly higher (p < 0.001) post-intermittent (15.1 % +/- 2.4) than post-continuous (10.3 % +/- 3.2) training. The lactate-exchange and removal abilities were also significantly higher for IT than for CT-group (P < 0.05). Moreover, IT-group showed a significantly shorter half-time of the blood lactate (t-1/2-[La]) than CT-group (7.2 +/- 0.5 min vs 7.7 +/- 0.3 min, respectively) (p < 0.05). However, no significant differences were observed in peak blood lactate concentration ([La](peak)), time to reach [La](peak) (t-[La](peak)), and [La]-(0) between the two physically-trained groups. We conclude that both continuous and intermittent training exercises were equally effective in improving t-[La](peak) and [La](peak), although intermittent training was more beneficial in elevating MAS and in raising the lactate exchange (gamma(1)) and removal (gamma(2)) indexes.