Training mode and lactate kinetics parameters International SportMed Journal, Vol. 9 No.4, 2008, pp. 172-181, http://www.ismj.com Official Journal of FIMS (International Federation of Sports Medicine) 172 ISMJ International SportMed Journal Original research article Adaptations of lactate kinetics to mixed and continuous training 1* Dr Adnene Gharbi, 2 Professor Karim Chamari, 1 Dr Imed Latiri, 1 Professor Zouhair Tabka, 2 Professor Abdelkarim Zbidi 1 Physiology Laboratory, Faculty of Medicine, Ibn el Jazzar, Sousse, Tunisia. 2 Research Unit for Evaluation, Sport, Health, National Centre of Medicine and Sciences in Sports (CNMSS), El Menzah, Tunisia Abstract The purpose of this study was to compare the differences in lactate parameters and maximal aerobic speed (MAS) adaptations to mixed and continuous training. Twenty-four subjects were equally divided into continuous (CT) (age 21.3± 1.2 years; body mass 69 ± 3kg; height 172 ± 2cm) or mixed (MT) (age 20 ± 2 years; body mass 68.5 ± 4kg; height 171 ± 3cm) training groups. Another six participants (age 21± 1.2 years; body mass 69.3 ± 3.4kg; height 174 ± 5cm) acted as non-training controls (CG). The trained participants practiced 6d/wk 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. Blood lactate recovery curves from the supramaximal exercise were fitted to a bi-exponential time function. Following the training period, there was a significant increase in MAS, a significant increase in lactate exchange (γ 1 ) and removal (γ 2 ) abilities (P<0.001), a significantly faster time to peak lactate (t-[La] peak ) (P<0.001), a significant decrease in lactate half time (t-½-[La] ) (P<0.001) , and significantly higher lactate concentration at the beginning of the recovery for both the continuous and mixed training groups(P<0.05). The increases in MAS was significantly higher (P<0.001) in MT-group compared to CT-group (15.6 ± 3.1% vs. 10.3 ± 3.2%). The lactate-exchange ability was also significantly higher post-mixed than post-continuous training (0.606 ± 0.099 min vs. 0.548 ± 0.237min) (P<0.05).However, no significant difference was observed in the other lactate parameters. These authors conclude that both mixed and continuous training were equally effective in altering t [La] peak , t-½-[La] and γ 2 ability, but mixed training was more effective in elevating both MAS and γ1. Keywords: bi-compartmental model, lactate metabolism, training mode, recovery, supramaximal exercise *Dr Adnene Gharbi, PhD Dr Gharbi is an Associate at the High Institute of Sport and Physical Education, South Univ., Gafsa, Tunisia. His main research interests are exercise- and training-induced metabolic changes. Professor Karim Chamari, PhD Professor Chamari is a professor in the National Centre of Medicine and Sciences in Sports (CNMSS), El Menzah, Tunisia. His main research interests are exercise and sports performance training and testing. Email: karimchamari@gmx.net * Corresponding author. Address at the end of text.