Hematological profile and martial status in rugby players during whole body cryostimulation.

Cold-based therapies are commonly applied to alleviate pain symptoms secondary to inflammatory diseases, but also to treat injuries or overuse, as done in sports rehabilitation. Whole body cryotherapy, a relatively new form of cold therapy, consists of short whole-body exposure to extremely cold air (-110°C to -140°C). Cryostimulation is gaining wider acceptance as an effective part of physical therapy to accelerate muscle recovery in rugby players. The aim of this study was to evaluate the effect of repeated cryostimulation sessions on the hematological profile and martial status markers in professional rugby players. Twenty-seven professional rugby players received 2 daily cryostimulation treatments for 7 consecutive days. Blood samples were collected before and after administration of the cryotherapic protocol and hematological profiles were obtained. No changes in the leukocyte count or composition were seen. There was a decrease in the values for erythrocytes, hematocrit, hemoglobin and mean corpuscular hemoglobin content, and an increase in mean corpuscular volume and red cell distribution width. Platelet count and mean volume remained unchanged. Serum transferrin and ferritin decreased, while soluble transferrin receptor increased. Serum iron and transferrin saturation were unchanged, as was reticulocyte count, whereas the immature reticulocyte fraction decreased substantially. In conclusion, in this sample of professional rugby players, cryostimulation modified the hematological profile, with a reduction in erythrocyte count and hemoglobinization paralleled by a change in martial status markers.

Criterion and longitudinal validity of a fixed-distance incremental running test for the determination of lactate thresholds in field settings.

The aim of this study was to examine the criterion validity of 2 lactate thresholds (LTs, intensity corresponding to 1 mmol·L(-1) above baseline; onset of blood lactate accumulation, intensity at 4 mmol·L(-1)) determined with a fixed-distance incremental field test by assessing their correlation with those obtained using a traditional fixed-time laboratory protocol. A second aim was to verify the longitudinal validity by examining the relationships between the changes in LTs obtained with the 2 protocols. To determine the LTs, 12 well-trained male middle and long distance amateur and competitive runners training from 4 to 7 d·wk(-1) (age 25 [5] years, body mass 66 [5] kg, estimated VO(2)max 58.6 [4.9] ml·min(-1)·kg(-1), SD in parentheses) performed in 2 separate sessions an incremental running test on the field starting at 12 km·h(-1) and increasing the speed by 1 km·h(-1) every 1,200 m (FixD test) and an incremental treadmill test in the laboratory starting at 12 km·h(-1) and increasing the speed by 1 km·h(-1) every 6 minutes. The 2 tests were repeated after 6-12 weeks. A nearly perfect relationship was found between the running speeds at LTs determined with the 2 protocols (r = 0.95 [CI95% 0.83-0.99]; p < 0.001). The correlations between longitudinal changes in LTs were very large (0.78 [0.32-0.95; p = 0.006]). The heart rate corresponding to the LTs were not significantly different. This study showed the criterion and longitudinal validity of LTs determined with a protocol consisting of fixed-distance intervals performed in field setting.

Reticulocyte count, mean reticulocyte volume, immature reticulocyte fraction, and mean sphered cell volume in elite athletes: reference values and comparison with the general population.

BACKGROUND: The role of measurement of reticulocytes and their parameters is growing in sports medicine. The use of reticulocyte counts in protocols for evaluating and screening for the suspected abuse of hormones that stimulate the bone marrow is an example. Reticulocytes are also important for evaluation of the performance and general health status of athletes, especially for monitoring therapies and diets. The current availability of fully automated haematological systems that can measure reticulocyte numbers and characteristics (volume, density) increases the potential use of these parameters in laboratory and sports medicine. Few studies have considered the application of these parameters in athletes and a lack of specific reference ranges means that their valid clinical use is difficult. METHODS: Using a Coulter LH700 instrument, we measured reticulocyte count (Retics), mean reticulocyte volume (MRV), immature reticulocyte fraction (IRF), and mean sphered cell volume (MSCV) in 106 male professional elite athletes (football and rugby players and skiers). Reference intervals for the athletes were compared with the intervals found for a control group of 73 age-matched males. RESULTS: We calculated the following reference intervals: 0.30-1.54% for Retics, 93.1-114.8 fL for MRV, 0.18-0.39% for IRF, and 76.8-94.5 fL for MSCV. CONCLUSIONS: No statistically significant differences were observed for Retics, MRV, IRF, and MSCV between elite athletes and controls. Significant differences were observed for haemoglobin (Hb), erythrocytes, haematocrit (Ht), and mean corpuscular volume. Moreover, no statistical differences were observed among different sports, whereas differences were remarked in football and rugby players between the samples drawn before the start of competitive season and the samples drawn during the season, demonstrating that reticulocyte counts and parameters are useful for monitoring sportsmen.