Impact of Whey Protein on Canoeing Athletes in Training and the Mechanism

Sports completion is unprecedentedly intensive now and performance of athletes becomes closer and closer to limit of human’s capacity. To constantly create better performance, athletes must do a large amount of limitation training. Athletes would be found with water desorption, electrolyte loss, enhanced protein catabolism, imbalanced cell membrane penetration and enzyme escape after overloaded training and competition. Whey protein can rapidly provide athletes with water, electrolyte and energy substance, prevent excessive fatigue of athletes during sports, sustain and promote fluid balance within body and help athletes rapidly recover physical ability. Sports nutritional food is a powerful nutritional basis for athletes who engage in a large amount of overloaded training and competition. This study first discusses over the application of whey protein in the perspective of the functional characteristics of whey protein, then emphatically analyzes the impact of whey protein on physical ability recovery and fatigue elimination of canoeing athletes and finally explores the impact of whey protein on various indexes during training based on a case, thus to further confirm the action mechanism of whey protein for canoeing athletes.


INTRODUCTION
compared the antitumor effect of whey protein and casein through animal and in vitro test and found whey protein was more effective in inhibiting growth of cells of prostatic cancer, breast cancer and colon cancer compared to casein and lower the incidence rate of tumor for 50%.Frid et al. (2006) once researched the influence of whey protein on blood glucose on 14 cases of type II diabetics and found whey protein could reduce the increasing degree of blood glucose in 2 h after breakfast and 3 h after lunch.Study of Morifuji et al. (2005) suggested that, whey protein could restrain activity of liver, remove fat accumulation in body and meanwhile stimulate muscle tissues to store energy substance for adapting to long-time uninterrupted endurance training.By comparing the effect of whey protein and soy protein on white mouse suffering loaded exercise, (Elia et al., 2006) found whey protein strengthened antioxidant activity through changing concentration of free radical and glutathione, while soy protein improved antioxidant activity by changing substrate concentration of thiobarbituric acid reaction.They thought taking either of them both can help body endure more intensive training.It has been found that, whey protein can keep nice nutritional state and prevent loss of muscle tissue, thus delay aging (Mackenzie-Shalders et al., 2015).Moreover, supplementing whey protein can strengthen muscle circumference of the upper arm of canoeing athletes, promote synthesis of muscle and sustain and improve the level of testosterone (Liao et al., 2007;Mackenzie-Shalders et al., 2015).Whey protein can help reduce weight, control blood glucose and promote secretion of insulin, which is beneficial to recovery of diabetics (Pan et al., 2012).Thus this study analyzes the effect of whey protein on physical ability recovery and fatigue relief of athletes in the aspect of action mechanism of whey protein on canoeing athletes.

Functional characteristics of whey protein and its application in sports nutrition:
Characteristics of whey protein: Whey protein, a protein condensed from whey produced during production of cheese or extracted from milk, is composed of tiny and tight globular proteins and has special amino acid sequence and three dimensional structures.Whey protein contains more than twenty amino acids.Except sulfur-containing amino acid, other amino acids that are needed by human body account for a high proportion.It has been found that (Samadi, 2009), whey protein is effective in strengthening power of muscle, improving environmental inside body, accelerating recovery of physical ability and enhancing sports performance of athletes.Moreover, whey protein contains multiple functional activity substance (Bordi et al., 2003) including β-lactoglobulin, α-lactoglobulin, serum albumin, immune globulin, lactoferrin, lactoperoxidase, growth factor and glycomacropeptide.Whey protein characterized by high protein, low cholesterol, low lactose and low fat and easy to digest is of high nutritional value; therefore, it is called the king of protein.
Branched chain amino acids such as leucine and isoleucine accounting for 26% in whey protein can provide energy as energy source; whey protein also contains glutamine, lysine and arginine which can help update inosose., prevent immunocompetence decline due to excessive sports, stimulate synthesis and secretion of synthesized metabolic hormone and strengthen growth of muscle; as the source of sulfurcontaining amino acid such as methionine and cysteine, it can maintain the content of glutathione inside body; as a good source of threonine, it can protect intestinal cells and intestinal tract barrier continuity; moreover, it is beneficial for preventing osteoporosis (Xu et al., 2011).
Functional characteristics: Whey protein composing of some tiny and tight globular proteins such as lactoglobulin, immune globulin, growth factor and glycomacropeptide has a special three dimensional structure.It has functions such as lowering blood fat, blood sugar, antioxidation, anti-aging and anti-tumor, enhancing immunity and strengthening body constitution (Jakopović, 2014).Ingredients and corresponding biological activities of whey protein are shown in Table 1.

Application of whey protein in sports nutrition:
Whey protein is widely applied in food, medicine and cosmetic, fine chemical engineering and fodder industry for its healthcare functions and multiple physicochemical properties.Sports nutrition aims at maintaining the balance of environment inside body by supplementing water, energy and nutritional substance, thus to improve sports ability; relieve fatigue and recovery physical ability.Athletes require more than non-sports or labor individuals and the demand quantity is determined by sports time, sports category and loading quantity.American Diet Committee has pointed out that, ordinary athletes should take 1.5 g protein every day and the dose for those who do strength sports is more than 2.0 g every day.Lack of protein would result in negative nitrogen balance (Sundell et al., 2011) which can strengthen catabolism and delay physical ability recovery.But there is no protein that can be completely utilized.Excessive uptaking of proteins may boost metabolic stress; therefore, only high-quality proteins are quailed.Based on the requirements of sport nutrition, ideal proteins should be characterized by easy to digest, high bioavailability, balance between necessary amino acid and unnecessary amino acid, rich content of branched chain amino acid and low content of cholesterol and fat.Characteristics of proteins determine its high sports nutritional value.
Besides, whey protein is able to strengthen muscle powerful of athletes, improve composition of body and maintain and enhance immunity of athletes during training.

IMPACT OF WHEY PROTEIN ON PHYSICAL ABILITY RECOVERY AND FATIGUE RELIEF OF ATHLETES
Impact of whey protein on blood volume of canoeing athletes: Whey protein can improve immunity of sports body (Devries and Phillips, 2015), strengthen muscle strength of sports body and resisting antioxidation, damage and fatigue.Whey protein obtains wide application for its various sports nutritional performance.Supplementing whey protein timely can prevent significant decline of hemoglobin and maintain the functions of hemoglobin.In addition, it has been found that, whey protein drinks can reduce level of creatine kinase in serum and keep the stability of blood sugar concentration, thus to prevent occurrence of central fatigue and sustain functions of skeletal muscle (Silverberg, 2012).Hematocrit level inside body of athletes is observed to be significantly improved after supplementation of whey protein; therefore, whey protein drinks is effective in preventing reduction of blood volume.Therefore, supplement of whey protein of canoeing athletes can effectively protect functions of red blood cell, prevent decrease of CMC level, enhance rapid recovery of physical energy, promote relief of fatigue and maintain microstructure of muscle.

INSTANCE ANALYSIS
Whey protein is of high sports nutrition value.In the following, we discuss over the impact of whey protein on training by combining oral administration of whey protein and sports experiment.As application of whey protein in plateau training is seldom researched, especially for those high-level national canoeing athletes, we observe the changes of morphology and serum hormones after plateau training of canoeing athletes after being administrated with whey protein.
Research scheme: Athletes were divided into experimental group and control groups.Observation group took 50 g whey protein every evening, while control group took equicaloric carbohydrate.The whey protein (purity 80%) used is produced by Suli Xinchuang Company.During experiment, athletes are forbidden to take other nourishment.Moreover, diet was made according to menu.Caloric intake ratio of breakfast, lunch and dinner should be controlled at 3:4:3.

Changes of indexes of canoeing athletes after supplement of whey protein:
In the 45 th day, experimental group tended to have increased weight and control group increased slowly.Percentage of body fat was significantly declined both in experimental group and control group, while thigh circumference tended to increase.Waist circumference in experimental group has large increasing amplitude, but declined slightly in control group.In addition, subcutaneous fat of two groups both decline, but there was no statistical significant difference; but control group rose again after plateau training was over.
Meanwhile, skinfold thickness of upper arm was measured.Supposing subcutaneous fat to distribute evenly along the circumference, we calculated tight circumference of upper arm.Other indexes are shown in Table 2.
Before plateau training, there was no statistical significant difference of serum testosterone level between experimental group and control group; but in the subsequent measurement, the level in control group was lower than experimental group and a statistically significant difference was found.Level of estradiol showed a rising tendency in the whole process of test in both groups.In the 45 th day, estradiol level in control group had significantly higher than before training.Moreover, estradiol/testosterone tended to rise in experimental group and the ratio in control group remained unchanged.In the third week of training, testosterone and estradiol both decreased (Table 3).
Biochemical test suggest that, level of testosterone had no statistical significant difference between experimental group and control group, but under the stimulation of plateau training, level of testosterone in control group became 10% lower than experimental group.
Plateau training improves sports ability though double stimulation of high altitude anoxia and sports

CONCLUSION
With the development of modern sports, improvement of sports skills and performance cannot separate from research on nutrition.Nutritional diet is effective in maintaining health and enhancing sports performance of athletes.During training and competition, canoeing athletes consume considerable energy; if there are no enough nutritional supplements, recovery of body functions would be influenced.Protein, a nutritional element necessary in tissue metabolism and a basic ingredient of body tissue, is an important substance for maintaining basic activities of body and is also correlated to sports ability related multiple factors such as muscle contraction, substance metabolism and regulation of physiological function.Whey protein is widely applied as a sports nutritional supplement for its high purity, low fat, low cholesterol, high absorption rate, reasonable composition of amino acids and multiple healthcare functions (Almeida et al., 2015).

Table 1 :
Ingredients and biological activities of whey protein

Table 2 :
Changes of various indexes of athletes in two groups during training

Table 3 :
Changes of testosterone, estradiol and estradiol/testosterone in training cycle , it can result in large consumption of energy and induce fatigue.Thus it is necessary to supplement nutritional substance.Whey protein has a high proportion of branched chain amino acid and a low content of fat and cholesterol; therefore, whey protein as a nutritional supplement is able to enhance various indexes of canoeing athletes who engage in plateau training.