Trained Football Players Research Articles

Red Blood Cell Variables in Young and Mature High-Trained Football Players

A suboptimal values of the haematological variables has often been recorded in young athletes involved in intense physical activity. There have even been reports of “sports anemia” associated with intensive physical training. There are profound studies describing the haematological changes of the soccer players after training or 90 min match. Our previous studies demonstrated lower values of red blood cell count (RBC), packed cell volume (HCT), haemoglobin concentration (HGB) in highly trained football players than in untrained controls of the same pubescent age.THE AIM: It was a matter of interest to evaluate the haematological status of 2314 football players (15.11±2.89 yrs old) and to compare the results for pre-pubescent, pubescent and mature boys recruited in the study and also to relate the values obtained to the individulal aerobic functional capacity.MATERIAS: A total of 2314 highly trained football players were included in the study. Their mean±SD age, weight, and BMI were: 15.11±2.89 yrs, 56.33±13.28 kg, and 19.62±2.58 kg/m2. The sportsmen were divided into three groups in accordance with their age: pre-pubescent (9–14 years) group A (n=1178) − 13.22±1.05 yrs (158.6±12.6 months); pubescent (15–19 years) group B (n=1029) − 16.57±1.04 yrs (198.9±12.6 months); and mature (20–35 years) group C (n=107) − 24.30±3.78 yrs (291.6±45.3 months) old. Profound clinical examination of all sportsmen was performed at the day before obtaining the blood samples. Haematological variables including RBC, HCT, HGB, mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin content (MCHC), white blood cell count (WBC) and platelet count (PLT) were analysed on a Sysmex K800 (Japan) analyser. Each football player passed also PWC170-test for assessment the working capacity on AT-104 Spiro-Ergo equipment (Schiller, Switzerland).RESULTS: All haematological variables in the groups were found in normal ranges, but the RBC was highest in group B (5.17±0.28 *1012/l vs. 5.03±0.28 *1012/l for group A, and 5.08±0.41 *1012/l for group C). Group A demonstrated not only lowest values for the RBC, but also for the HGB (144.7±6.4 g/l vs. 149.1±6.0 g/l for group B, and 151.8±7.5 g/l for group C, P<0.001), and for HCT (0.437±0.02 vs. 0.451±0.02 for group B, and 0.451±0.03 for group C, P<0.001). Group A demonstrated similar values for the above basic red blood cell parameters to these measured for great male group of same age. The pre-pubescent football players (group A) had lower MCV (87.1±2.8 fl), than the players of group B (87.5±2.9 fl) and than the players from group C (88.1±3.0 fl). No evidences for blood dilution as a result of long-term training had been found in groups B and C. There was not difference in the WBC and PLT between pre-pubescent, pubescent and mature footballers. The mature players (C-group) demonstrated higher PWC/kg than pre-pubescent (20.6±2.3 vs. 19.2±2.3 kgm/min/kg), and than pubescent boys (19.8±2.7 kgm/min/kg). Significant correlations were obtained between the age and HGB, and between the age and HCT in groups A (0.19 and 0.19 respectively) and B (0.24 and 0.15 respectively). Good correlations were found between RBC and PWC170/kg in all groups investigated.CONCLUSIONS: Pre-pubescent highly trained football players have lower values of the red blood cell variables than pubescent and mature footballers, which correlates with lower aerobic working capacity.

Sickle Cell Trait

Sickle cell trait can pose a grave risk for some athletes. In the past few years, exertional sickling has killed nine athletes, including five college football players in training. Exercise-physiology research shows how and why sickle red cells can accumulate in the bloodstream during intense exercise bouts. Sickle cells can "logjam" blood vessels and lead to collapse from ischemic rhabdomyolysis. Diverse clinical and metabolic problems from explosive rhabdomyolysis can threaten life. Sickling can begin in 2-3 minutes of any all-out exertion, or during sustained intense exertion--and can reach grave levels very soon thereafter if the athlete struggles on or is urged on by coaches despite warning signs. Heat, dehydration, altitude, and asthma can increase the risk for and worsen sickling. This exertional sickling syndrome, however, is unique and in the field can be distinguished from heat illnesses. Sickling collapse is a medical emergency. Fortunately, screening and precautions can prevent sickling collapse and enable sickle-trait athletes to thrive in their sports.

Fluid and electrolyte intake and loss in elite soccer players during training.

This study measured fluid balance during a 90-min preseason training session in the first team squad (24 players) of an English Premier League football team. Sweat loss was assessed from changes in body mass after correction for ingested fluids and urine passed. Sweat composition was measured by collection from patches attached to the skin at 4 sites. The weather was warm (24-29 degrees C), with moderate humidity (46-64%). The mean +/- SD body mass loss over the training session was 1.10+/- 0.43 kg, equivalent to a level of dehydration of 1.37 +/- 0.54% of the pre-training body mass. Mean fluid intake was 971 +/- 303 ml. Estimated total mean sweat loss was 2033 +/- 413 ml. Mean sweat electrolyte concentrations (mmol/L) were: sodium, 49 +/- 12; potassium, 6.0 +/- 1.3; chloride, 43 +/- 10. Total sweat sodium loss of 99+/- 24 mmol corresponds to a salt (sodium chloride) loss of 5.8 +/- 1.4 g. Mean urine osmolality measured on pre-training samples provided by the players was 666 +/- 311 mosmol/kg (n = 21). These data indicate that sweat losses of water and solute in football players in training can be substantial but vary greatly between players even with the same exercise and environmental conditions. Voluntary fluid intake also shows wide inter-individual variability and is generally insufficient to match fluid losses.

THE QUANTITY AND QUALITY OF EXERCISE FOR HEALTHY ADULTS

THE QUANTITY AND QUALITY OF EXERCISE FOR HEALTHY ADULTS

Postexercise increase in nitric oxide in football players with muscle cramps.

Nitric oxide, a free radical inter- and intracellular messenger molecule, is important in exercise physiology. This study tested the hypothesis that serum nitric oxide concentrations change after strenuous exercise with severe generalized muscle cramps. The study group consisted of 77 professional football players in preseason training. All players' concentrations of serum nitrite and of other serum chemicals were determined during their preseason evaluations and compared with the concentrations in 40 serum samples taken from 25 of those same players who required intravenous rehydration for severe generalized muscle cramps after a training session. Player weight and percentage of body fat were significantly higher in players who received intravenous fluids than in players who did not. The serum of players requiring intravenous hydration showed evidence of skeletal muscle breakdown (increases in lactate dehydrogenase, creatinine phosphokinase, aspartate aminotransferase, and alanine aminotransferase) and of dehydration (elevations in protein, blood urea nitrogen, and cholesterol). The major finding, however, was a nearly 300% increase in serum nitrite concentrations in players requiring rehydration. There were no correlations between concentrations of nitrate and of any of the other serum chemicals. These data support the hypothesis that large amounts of nitric oxide are synthesized in professional football players after strenuous exercise with severe muscle cramps. The study design did not allow us to determine whether this increase in nitric oxide was due to exercise or muscle cramps or both, but it does provide a basis for evaluating these relationships.

Androgen levels following a football match.

In 18 trained football players, blood samples were collected before a football match, at half-time, at the end, and 45 and 90 min after the end of the match. The testosterone (T) level showed a decrease in the rest period. Dihydrotestosterone (DHT) increased during the match, but returned to initial levels in the last samples. The T/DHT ratio decreased, reached the minimal value at the end of the exercise, and returned to basal levels in the rest period. Cortisol and androstenedione levels increased during the match, but returned to control levels 45 and 90 min after the end of the match, respectively. It is suggested that during this type of exercise anabolic and catabolic hormones may be simultaneously activated.

THE EFFECTS OF CERTAIN PHYSICAL AND EMOTIONAL TENSIONS AND STRAINS ON FLUCTUATIONS IN THE LEVEL OF SERUM PROTEIN-BOUND IODINE

ABSTRACT The effect of physical and emotional tensions and strains on the fluctuation of the serum protein-bound iodine level was studied in groups of healthy people and in two groups of patients. The effect of the tension and strain of examination was observed in 11 medical students preparing for annual examinations and in 11 Royal College of Physicians candidates. The stress of athletic contest on the protein-bound iodine level was observed in 7 professional football players in training and during their scheduled games. There was no fluctuation beyond that found in normal healthy persons. Similarly, in 8 patients prior to and following major operations and in 9 patients following myocardial infarction, the fluctuations of the serum protein-bound iodine level remained within the usual normal range. Our data fail to provide any evidence that the function of the normal thyroid gland is readily affected by severe mental and physical stresses or strains.