Effects Of Weight Loss On Sports Fatigue In Amateur Male Boxing Athletes

Objectives:To investigate influences of the weight loss and control before competitions upon sports fatigue in light-heavyweight amateur men boxing athletes, and to provide references in making a logical rapid weight-loss plan, finding a logical weight-controlling approach, avoiding or reducing the sports fatigue causing by the loss and control of weight, and achieving the best competitive status.Methods:Eight athletes in Fujian Provincial Men’s Boxing Team were enrolled, and their physiological and biochemical parameters, such as training load, sports performance and sports fatigue, to grasp the boxing players’holding capacity to training under the status of loss and control of weight, and also to grasp the situation of sports fatigue, were systematically observed and detected in 1 year. Methods for weight controlling include both arrangement for the training loads before competition and arrangement for the rhythm of loss and control of weight before competition. Before the competition, the following indexes shall be detected-- heart rate (HR), blood lactic acid (Bla), creatine kinase (CK), blood urea (BU), blood serum testosterone (T), hemoglobin (HB), red blood cell (RBC), hematocrit(HCT), white blood cell (WBC), mean corpuscular hemoglobin (MCH). mean corpuscular hemoglobin concentration(MCHC), erythrocyte hemoglobin distribution width (RDW). urokinase protein (Pro), urobilinogen (URO), specific gravity of urine (SG), Urine occult blood(BLD), urine acetone bodies (KET) and self subjective feeling; the data for changes of all the indexes before and after the loss of weight shall be counted and then carried out paired t-test, and to carry out Pearson Analysis for relative indexes of sports fatigue and sports ability.Results:1) After a weight-losing measure of 6 to 8 weeks, the player’s weight declines by 4.13kg on average (the most by 7kg, and the least by 2kg, p<0.001); the percentage of body fat declines by 8.76% on average (p= 0.018), which shows outstanding changes. 2) The player’s red blood cell indexes including RBC、HCT、MCH、MCHC、RDW, have significant differences before and after the weight-losing measure, a significant climbing of MCHC without significant difference of urine indexes. For HB, the index climbs but the change is not so significant. And for blood serum T and BU, there is no significant difference, either.3) After theloss and control of weight, the player’s ability of sports load declines without a significant difference.4) The investigation of individual cases shows that due to a continuously vast scale of loss and control of weight or an unsuitable measure, the player’s physical fitness will decline significantly and causes the sports fatigue.Conclusion:1) The measure of loss and control of weight will cause a significant declining of percentages of weight and body fat.2) The measure of loss and control of weight will cause a significant change of blood indexes, which can be an important basis to monitor the sports fatigue.3)Different from the past investigations, we find that the significant climbing of hematocrystallin could be related with the climbing of viscosity of blood, being caused by dehydration in weight losing. The change of blood serum T is not so significant, which shows that the measure of loss and control of weight and training may be reasonable.4) The research shows that the relation between the changes of indexes for blood and urine and heart rate during practical competition by weight losing is not significant. Besides, there is a significantly negative correlation between change of Bla and change of blood MCV after an exercise of 3 minutes, i.e., the MCH will climb with the declining of Bla after weight losing for 3 minutes. And after the weight losing, the heart rate has a significantly negative correlation with change of URO after an exercise of 1 minute.5) The heart rate after the 4-round practical competition is nearly the same as that of 1 minute of practical competition, which indicates that players’ physical fitness will not effected by weight losing.6) The individual research shows that the weight losing of boxing players will not cause a sports fatigue.7) The range of sports fatigue is influenced by such factors as loss and control of weight and players’basic physical fitness before the loss and control of weight.8) A scientific plan of the loss and control of weight can decrease the effect of loss and control of weight to physical fitness, and can also reduce the risk of sports fatigue.