Anaerobic threshold in running and swimming rats: determination using two mathematical methods - doi: 10.4025/reveducfis.v21i2.7681

Abstract

The study aimed to determine the anaerobic threshold (AT) with incremental test in swimming and running rats, using two mathematical methods for analysis: fixed blood lactate concentration and visual inspection of inflection point preceded by bi-segmental linear regression. Swimming (n=19) and running rats (n=29) were used. The incremental test was composed by 5 minutes of exercise with blood collection after loads for lactate concentration determination. The AT was determined by fixed lactate concentration (4.0; 4.5;5.0; 5.0mmol/L) and the visual inspection of inflection point of the lactate curve, preceded by intersection of the bi-segmental linear regression. The AT intensities were compared by one-way Anova. In swimming rats the best analysis for AT determination seems to be fixed blood lactate in concentrations (5.0 and 5.5mmol/L, load=4.2±0.1%bw). In treadmill running, the bi-segmental linear regression was possible with 67.2% of animals (AT=21.1±0.9 m/min) and this method seems to be the adequate for running rats.