We assessed the responses of hematological parameters and their relationship to the anaerobic threshold of Brazilian soccer players during a training program. Twelve athletes were evaluated at the beginning (week 0, T1), in the middle (week 6, T2), and at the end (week 12, T3) of the soccer training program. On the first day at 7:30 am, before collecting the blood sample at rest for the determination of the hematological parameters, the athletes were conducted to the anthropometric evaluation. On the second day at 8:30 am, the athletes had their anaerobic threshold measured. Analysis of variance with Newman-Keuls'post hoc was used for statistical comparisons between the parameters measured during the soccer training program. Correlations between the parameters analyzed were determined using the Pearson's correlation coefficient. Erythrocytes concentration, hemoglobin, and hematocrit were significantly increased from T1 to T2. The specific soccer training program led to a rise in erythrocytes, hemoglobin, and hematocrit from T1 to T2. We assumed that these results occurred due to the plasma volume reduction and may be explained by the soccer training program characteristics. Furthermore, we did not observe any correlation between the anaerobic threshold and the hematological parameters.

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The main purpose of the present investigation was to verify the responses of hematological parameters in men and women competitive swimmers during a 14-week training program. Twenty-three Olympic and international athletes were evaluated 4 times during the experiment: at the beginning of the endurance training phase (T1), at the end of the endurance training phase (T2), at the end of the quality phases (T3), and at the end of the taper period (T4). On the first day at 8:00 AM, each swimmer had a blood sample taken for the determination of hematological parameters. At 3:00 PM, the athletes had their aerobic performance measured by anaerobic threshold. On the second day at 8:00 AM, the swimmers had their aerobic performance measured by critical velocity. Hematocrit and mean corpuscular volume diminished (p < or = 0.05) from T1 to T2 (men: 5.8 and 7.2%; women: 11.6 and 6.8%), and increased (p < or = 0.05) from T2 to T3 (men: 7.2 and 6.0%; women: 7.4 and 5.2%). These results were related to the plasma volume changes of the athletes. However, these alterations do not seem to affect the swimmers' aerobic performance. For practical applications, time-trial performance is better than aerobic performance (i.e., anaerobic threshold and critical velocity) for monitoring training adaptations.

The anaerobic threshold (AT) may be determined by protocols that use fixed blood lactate concentration (OBLA -onset of blood lactate accumulation) and others that apply individualized procedures as the lactate minimum test (LACmin). The measuring of the aerobic capacity from AT demands the use of sophisticated equipment and high cost per athlete, which makes it limited. The 12-minutes Cooper test is applied as an alternative way. The main objective of the present study was to compare the exercise intensity of a 12-minute Cooper test with the velocities of AT determined by protocol adapted from Tegtbur test (Lac minat ) and OBLA in professionals soccer players. Sixteen athletes from the A3-São Paulo State Soccer league participated in this study. Each athlete was available in the three tests with a minimum and maximal interval of 48 and 72 hours, respectively. The results show that the intensities obtained in the Cooper test were different from the OBLA velocities (15.09 ± 0.94 and 14.28 ± 1.02, respectively) but were significantly correlated. Cooper and OBLA were not correlated with Lac minat , but the velocities were similar to this protocol test. Thus, from regression analysis between Cooper and OBLA values, it was possible to determinate a correction equation that allows, through a non-invasive test (Cooper), obtaining the velocity corresponding to OBLA.