Nutrition is essential for one and all. Research has shown that optimal nutrition is critical for both physical and mental performance. Optimal nutrition means that which is neither excess nor deficient. Optimal nutrition has an important role in the performance of sportsmen. Nutrition is also important during practice and training sessions so that overtraining does not occur. The type of nutrition essential for each sport is different depending on the level of physical activity involved. Ice hockey is one of the high range sports which require high intensity training and also high intensity performance.
This research explores the optimal nutrition requirement of ice hockey athletes. Energy requirements of ice hockey The human body expends energy in one of three ways: through the basal metabolic rate, through thermogenesis, or through physical activity. The basal metabolic rate is the minimum amount of energy expenditure required to carry on normal biological functions and reactions in the body, such as breathing, keeping the heart beating, and carrying out the process of waste management. It accounts for roughly 75% of the daily energy expenditure.
Physical activity deals with energy expended during periods of exercise, and it accounts for around 18% of total energy expenditure. Dietary thermogenesis is the energy expenditure required for the digestion, absorption, and transportation of food. Some individuals expend more calories in thermogenesis than others, and this phenomenon accounts for the slight metabolic differences between obese and lean individuals. Dietary thermogenesis accounts for 7% of energy expenditure (“The Weight Loss Equation” 2004).
While basal metabolic rate and dietary themogenesis remain almost same for all, physical activity varies from individual to individual and from one sport to another. Ice hockey is a fast-paced, physical team sport which is played on ice. The sport involves intermittent high intensity skating, rapid changes in duration and velocity and also frequent body contact (Montgomery, 1988). Typically, a player performs for about 15 to 20 minutes in a game which lasts for 60 minutes. Each shift lasts for about 30 to 80 seconds which is followed by a 4- 5 minute recovery time (Montgomery, 1988).
Each shift is a high intensity burst demanding good muscle strength and power and also anaerobic endurance. Heart rates during a shift exceed 90% HR max. Blood lactate levels soar during the game proving that ice hockey is anaerobic in nature. Both anaerobic and aerobic systems of energy are important for performance in the game. When energy is derived after combustion of carbohydrates and fat in the presence of oxygen, it is known as aerobic metabolism. The by-products of such a metabolism are carbon-di-oxide and water which are disposed off through breathing and sweating.
Aerobic metabolism comes into picture for energy expenditure during rest and low intensity exercises or physical activity. During this type of metabolism, energy is derived from glucose and fat in the presence of oxygen. The stored glycogen in the muscles is broken down to glucose which is further broken down using oxygen to create energy. When glycogen stores are depleted, fat metabolism is initiated for energy replenishment. Fat metabolism is a slow process and when this is used for energy, performance declines.
As the intensity of physical activity progresses, energy begins to be derived from anaerobic metabolism where energy is produced from glycogen or sugar in the absence of oxygen. This is because higher intensities of exercise need more energy which cannot be supplied by aerobic metabolism. The change from aerobic metabolism to anaerobic metabolism is known as metabolism threshold. The waste products of anaerobic metabolism are pyruvic acid and lactic acid which cause fatigue and soreness in the muscles (Scott, 2005). Anaerobic exercise is much less efficient that aerobic exercise and hence requires lot of training.
The first thing in a sport like ice hockey is to ensure that the player is consuming sufficient number of calories so that energy can be spent. Ice hockey involves intense training. Players of this sport expend atleast 600-1200kcals during workout. Hence ideal calorie requirements of these athletes are about 50- 80kcals/kg/day which amounts to 2500- 8000kcals/day for a 50-100kg weighing athlete. Some may even require 12,000kcals/day (Casa et al, 2000). According to the Canada Food Guide (qtd. in Bullard, 1978), essential components of food for any individual are proteins, fat and carbohydrates.
These must be blended in such a way that they contain sufficient essential minerals and vitamins. There are four basic foods which make this possible. They are 2- 4 servings of milk or milk products like whole or 2% skim milk, butter milk, reconstituted evaporated or dry milk and cheese, 3- 5 servings of bread and cereals, 2 servings of meat and alternates like poultry, liver, fish, lean meat, cooked dried peas, nuts, beans or lentils, cheddar, cottage cheese, processed cheese and eggs, and 4- 5 servings of fruit and vegetables. This food can supply about 1000 to 1400 calories per day.
Additional calories can be supplied by increasing the number or size of servings. Each individual has different needs of calories and nutrients based on the age, sex, size of body, daily activities and growth. For athletes, extra nutrition is essential not only to maintain body weight, but also to allow for exercise, training and competition. Consuming energy deficient diet leads to weight loss, muscle mass loss, physical symptoms, psychological symptoms of over training and also performance reduction. In females, eating disorders can develop (Krieder et al, 2002).
Muscle strength Muscle strength is very essential for ice hockey playing because shifts involve intense body contact and high intensity and high speed skating. To develop adequate muscle strength, appropriate training is essential. Elements of strength training include hypertrophy, maximal strength, explosive power, strength endurance and periodization. Hypertrophy of muscles is essential in ice hockey players because the sport is involved with aggressive body contact. However, too much bulk is a hindrance and hence only optimal hypertrophy is aimed at (Tikkaja et al, 2003).
Maximal strength is that force which can be generated by the athlete to the maximal level. Maximal strength is essential to generate explosive power during performance which is essential during shifts. Maximal strength training does not lead to hypertrophy of muscles (Hoff et al, 2002). Explosive power training involves training the athlete to contract muscles in a fast manner which is needed in shifts. Strength endurance is important in ice hockey because of the speed and high intensity burst that the sport demands.
Periodisation allows sports-specific strength to peak at the right moment, i. e. the shift. For a good training program to run, a well designed diet must be there which meets the needs of energy intake and also incorporates appropriate timing of nutrients. Research has proven that a good diet helps in the adaptation of training and a bad diet impedes adaptation to training (Krieder et al, 2002) Hydration Water accounts for 73% of lean body mass. During any exercise, evaporation of sweat occurs as a method to regulate the core temperature of the body.
The same is the case with ice hockey. Sweating causes loss of valuable fluids from the body which has only a finite reservoir of water. Hence if the lost fluids are not replaced in a timely manner, dehydration can result. Dehydration leading to 1-2% loss in body weight can compromise the physiologic function and thus affect performance (Casa et al, 2000). Once the loss of weight reaches 3%, exertional heat illnesses like heat exhaustion, heat cramps and heat stroke can occur (Casa et al, 2000). Dehydration during physical activity of sports is very common.
Dehydration can develop within one hour of physical activity or even in a shorter duration of time. Dehydration can be minimized or even prevented by following proper dehydration prevention protocols (Casa et al, 2000). One of the indicators of hydration during exercise sessions is to check weight before, during and after the sessions. This is useful provided the players enter the exercise session fully hydrated. This form of monitoring for fluid loss is reliable and helps the player rehydrate in a timely manner.
Another reliable method of monitoring hydration status is specific gravity checking of urine with a refractometer. Urine volume assessment and urine color comparison methods are less popular methods of hydration status assessment (Casa et al, 2000). According to the guidelines set by the National Athletic Trainer’s Association (Casa et al, 2000), an athlete must consume approximately 500- 600ml of water or sports drink 2- 3hours prior to practice session or game and about 200- 300ml of water or sports drink prior to onset of exercise.
During the game or practice session fluids must be consumed to make up losses. This can be done by taking 200- 300ml every 10-20 minutes. After the exercise, rehydration must be done to replace losses during the session. Electrolytes must also be included in the fluids to speed rehydration. Usually cool fluids are recommended so that the player takes more fluid inside. Bad signs and symptoms of dehydration include irritability, thirst, general discomfort, headache, dizziness, chills, vomiting, nausea and decreased performance.
Other dehydration signs include weariness, flushed skin, apathy and heat sensations on head and neck. Sodium chloride must be included in the fluid replacement beverage when there is inadequate access to meals. Modest amounts of sodium ranging between 0. 3- 0. 7g/L can offset salt loss which occurs in sweating. Ideal rehydration fluid An ideal rehydration fluid will consist of 60 grams of carbohydrate in 1 liter of fluid. This concentration of fluid will not hinder fluid absorption and at the same time will provide the required carbohydrate for refuelling (Casa et al, 2000).
Role of proteins Proteins are very essential when heavy work is done for prolonged periods and also during periods of growth. May sportsmen are of the opinion that proteins are the primary sources of energy for muscles. However, this is not true because, when other substrates are available, protein is seldom used for derivation of energy. A well balanced diet will have sufficient protein for building of muscles and hence there is no justification for the use of expensive high-protein diets (Casa et al, 2000). High intense trainers like ice hockey players will need about 1. – 2g per kg per day of protein which is twice the RDA recommendation for general population.
Insufficient protein intake can result in negative nitrogen balance which increases protein catabolism and slows recovery time. This can contribute to intolerance of training and loss of muscle mass. The type of protein consumed is also important. Best sources of protein include skinless chicken, egg white, skim milk and egg white (Krieder et al, 2004).. Role of fat Fat is very rich in calories. Each gram of fat when burnt, releases 9KCals.
However, metabolic breakdown of fat utilizes more oxygen and thus maximum physical efficiency is not possible when a diet which is rich in fat is consumed. However, some amount of fat is essential for flavouring of food, reservation of energy stores and body insulation (Casa et al, 2000). The dietary recommendations for fat intake in athletes are similar to those recommended for non-athletes. For an athlete, it is essential to maintain energy balance, replenish intramuscular triacyl glycerol and also take essential fatty acids (Krieder et al, 2004). Role of carbohydrates
During exercise, body uses 30-60 g of carbohydrates per hour. Ice hockey players will need 400-1500 grams of carbohydrate (50-150kg body weight) to maintain the glycogen levels of the muscle. Majority of the carbohydrate in the diet must come from complex carbohydrates which have low-to-moderate glycemic index. Some of such carbohydrates are starches, grains, maltodextrins and fruit. Since it is difficult to consume solid carbohydrate during intense training, experts recommend that carbohydrates may be taken in the form of concentrated carbohydrate juices and drinks (Krieder et al, 2004).
Vitamins Vitamins are essential for energy synthesis, prevention of cell destruction, maintenance of neurological processes and regulation of metabolic processes. Basically there are 2 types of vitamins, the fat soluble and the non-fat soluble. Vitamins A, D,E and K are fat soluble and Vitamins B and C are water soluble (Krieder et al, 2004). Athletes need as much vitamins as non-athletes. There is no evidence to definitely prove that increased vitamin consumption increases performance.