Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]

Periodized versus non-periodized swimming training with equal total training load: Physiological, molecular and performance adaptations in Wistar rats.

This study investigated the effect of non-periodized training performed at 80, 100 and 120% of the anaerobic threshold intensity (AnT) and a linear periodized training model adapted for swimming rats on the gene expression of monocarboxylate transporters 1 and 4 (MCT1 and 4, in soleus and gastrocnemius muscles), protein contents, blood biomarkers, tissue glycogen, body mass, and aerobic and anaerobic capacities. Sixty Wistar rats were randomly divided into 6 groups (n = 10 per group): a baseline (BL; euthanized before training period), a control group (GC; not exercised during the training period), three groups exercised at intensities equivalent to 80, 100 and 120% of the AnT (G80, G100 and G120, respectively) at the equal workload and a linear periodized training group (GPE). Each training program lasted 12 weeks subdivided into three periods: basic mesocycle (6 weeks), specific mesocycle (5 weeks) and taper (1 week). Although G80, G100 and G120 groups were submitted to monotony workload (i.e. non-modulation at intensity or volume throughout the training program), rodents were evaluated during the same experimental timepoints as GPE to be able comparisons. Our main results showed that all training programs were capable to minimize the aerobic capacity decrease promoted by age, which were compared to control group. Rats trained in periodization model had reduced levels of lipid blood biomarkers and increased hepatic glycogen stores compared to all other trained groups. At the molecular level, only expressions of MCT1 in the muscle were modified by different training regimens, with MCT1 mRNA increasing in rats trained at lower intensities (G80), and MCT1 protein content showed higher values in non-periodized groups compared to pre-training and GPE. Here, training at different intensities but at same total workload promoted similar adaptations in rats. Nevertheless, our results suggested that periodized training seems to be optimize the physiological responses of rats

Treinamento de natação na intensidade do limiar anaeróbio melhora a aptidão funcional de ratos idosos Swimming training at anaerobic threshold intensity improves the functional fitness of older rats

Os efeitos do treinamento aeróbio em intensidade relativa ao limiar de lactato (LL) foram analisados em 15 ratos idosos (~448 dias de vida). Os grupos de animais treinados (n=9) e controle (n=6) foram submetidos a um teste antes e após quatro semanas de treinamento. O teste incremental consistiu de uma carga inicial de 1% do peso corporal e incrementos de 1% a cada três minutos, com mensurações de lactato sanguíneo para identificação do LL por inspeção visual do ponto de inflexão da curva. O programa de treinamento consistiu de 30 minutos de natação/dia, cinco dias/semana, com sobrecarga de 5% do peso corporal (PC), ou controle sem exercício. Foi observado aumento significativo na intensidade do LL após o treinamento (pré = 4,5 ± 1,1 vs. Pós = 5.4 ± 0.9% PC). A carga máxima atingida ao final do teste incremental aumentou significativamente de 39,7 ± 7,5g no pré para 48,4 ± 10,5g no pós treinamento, sem mudanças para o grupo controle (44,7 ± 8 vs. 45,3 ± 9,3g). O peso corporal do grupo treinado não apresentou diferença como resultado de quatro semanas de natação em intensidade correspondente ao LL (641,0 ±62,0 para 636,0 ± 72.7g; p>0.05). Por outro lado, o grupo não treinado aumentou significativamente o PC de 614,0 ± 8,0 para 643,0 ± 74,1g. A carga máxima atingida expressa tanto em valores absolutos como relativos (%PC) aumentou significativamente após o treinamento. Conclui-se que quatro semanas de treinamento de natação em intensidade correspondente ao limiar de lactato resultou em uma melhora da aptidão aeróbia e na manutenção do peso corporal em ratos idosos.<br>The effects of aerobic training at the lactate threshold (LT) intensity were analyzed in fifteen older rats (~448 days old). Both the trained (n = 9) and control (n = 6) groups were submitted to an incremental exercise test before and after four weeks of training. The incremental exercise test consisted of an initial load of 1% BM and 1% increments at each 3-min with blood lactate measurements. The LT was determined by visual inspection of the blood lactate breakpoint. The training program comprised of 30-min swimming/day, 5 days/week, loaded with 5% body mass (BM), or control without exercise. Significant increase on the LT intensity after training (pre = 4.5 ± 1.1 vs. post = 5.4 ± 0.9% BM). The maximal workload reached at the end of incremental test increased significantly from 39.7 ± 7.5 g on pre to 48.4 ± 10.5 g at post training, with no changes for the control group (44.7 ± 8 vs. 45.3 ± 9.3 g). The body mass of the trained group did not change as a result of 4 weeks of swimming at LT intensity (641.0 ± 62.0 to 636.0 ± 72.7 g; p > 0.05). On the other hand, the untrained group increased significantly the BM from 614.0 ± 80.0 to 643.0 ± 72.7 g. The maximal workload, as expressed both in relation to absolute and relative values (i.e. %BM) increased significantly only as a result of training. It was concluded that four weeks of swimming training at LT intensity resulted in aerobic fitness improvement and body mass maintenance of older rats