How an athlete trains all year round can affect what supplementation and nutritional needs are appropriate to ensure certain goals and recovery. This article discusses the benefits of periodization along with nutritional timing that best suits what macro-cycle the athlete is in. For pre-season, the primary goal of an athlete should be to provide the body with sufficient carbohydrates and fuel on a consistent basis to support the energy needs during the day, and replenish the glycogen stores and intra-muscular proteins during recovery. Once the athlete is in-season, or competition, the ultimate goal is to maintain a moderate to high level of blood glucose. Training in the off-season is usually characterized by an increase in strength or power training, with a decrease in aerobic conditioning and post-exercise protein intakes within the hour after strength training should be added additionally to begin the synthesis of muscle proteins as early as possible.
Periodization is a widely used term in athletics. It is in reference to the organization of training into cycles of training objectives, tasks, and content. Historically, periodization was coined and adapted in the 1960s by Russian physiologist Leo P. Matveyev and Romanian sport scientist Tudor Bompa. Since then, several well-known scientists and researchers re-developed the model into the system that is currently used today in many realms of athletic participation. The system of periodization was established in order to help prevent overtraining and optimize peak performance in a sport. The cycles are specifically organized to allow an athlete to gain the most from his/her training, and will prepare them to peak during the competition phase of the year.
Periodization primarily centers on training and conditioning practices. However, the manipulation of dietary intakes and nutritional practices of the athletes throughout the various phases of the year is necessary in order to optimize the effects of training. This is based on a needs analysis of the athlete, with reference to the metabolic and physiological requirements during the particular phase of the year. If this does not occur, training may be hindered due to insufficient energy or a possible injury may occur due to improper recovery. The three primary macro-cycles, pre-season, in-season, and post-season will be reviewed with regards to goals and factors of nutritional requirements.
Pre-Season & Competition
The goals of pre-season football training are to prepare the athlete for competition. This is usually accomplished with the integration of aerobic as well as anaerobic training practices, and can occur multiple times a day. This places an extreme load on not only the energy requirements of the body to sustain the activities, but also the appropriate nutrients to provide the body with the fuel to recover and rebuild damaged tissues. Because of this characteristic, the primary goal of the diet is to prevent any nutritional deficiency from occurring. The term deficiency is not in this context related to the health and wellbeing of the athlete, but rather to the optimal intakes to produce the desired changes in body composition, muscular strength, power, and endurance. The effects of training alone do not determine the resulting changes, but rather the abilities of the body to adapt to the higher exercise stimulus. This adaptation is determined to a large extent by the nutritional practices adopted.
Fatigue in sports and exercise is the characteristic that is most often trained for improvement. The effects of training and the characteristics of an athlete’s physiology enable the athlete to sustain higher workloads for longer periods of time. With reference to fuel within the body, muscle and liver glycogen, or stored carbohydrates are the primary factors involved with muscular fatigue. When the body is unable to produce ATP from glucose, the workloads must be decreased to a point in which the metabolism of fats (beta-oxidation) can provide the necessary ATP for muscular contractions. It is with training that an increased ability of the athlete to metabolize fats for fuel occurs, and a delay the start of glycogen oxidation occurs. Factors associated with this include increased mitochondrial density, increased muscle blood flow, and increased activation of enzymes responsible for fatty acid metabolism. The primary goal of an athlete in pre-season football training should be to provide the body with sufficient carbohydrates and fuel on a consistent basis to fuel the energy needs during the day, and replenish the glycogen stores and intra-muscular proteins during recovery.
All of the values that will be given for intakes are listed as gram per kilogram bodyweight (g/kg/bw). Total daily carbohydrate consumption of the athlete during pre-season training should be near the upper end of the 7 to 9 g/kg bodyweight range, and perhaps towards the lower end during competition, depending on the subjective feelings of the athlete. Total intakes are not as important as timing before, during, and after training, as this will determine the consistent recovery of the athlete from multiple training sessions. Prior to training in the morning, following the 8 to 10 hour fast from sleeping, or prior to competition (2-4 hours), an athlete should be consuming .8 to 1.0 g/kg/bw, or about 90g of carbohydrates for a 220 lb football player. The timing and amounts will allow for optimal digestion and synthesis of energy stores before training. In the hour prior to training or competition, low-moderate glycemic carbohydrates can be consumed that may help to elevate blood glucose prior to activity. Research examining the effects of pre-exercise food intakes has shown that if the volumes or the glycemic index of the foods are too high, pre-exercise hypoglycemia may occur due to large increases in insulin. The result could be a premature onset of fatigue due to lowered blood glucose. Ultimately it is up to the athlete to determine pre-training food consumption. Factors that should be considered include gastric comfort and fatigue, both physical and mental in nature.
Protein intakes per meal throughout the day are approximately .2 to .4 g/kg/bw, or around 30 g of quality protein for a 220 lb football player assuming the athlete will consume 5 to 6 meals per day. This intake should be rather consistent to allow for the optimal re-synthesis of muscular proteins that are metabolized during the conditioning. The types of foods consumed during the day can be altered to allow for optimal digestion and absorption of nutrients. For instance immediately prior to and after training, either liquid or simple forms of protein and carbohydrates should be consumed. Both to allow for quicker metabolism, but also for the comfort of the athlete, who may not want to ingest whole foods in the hours immediately before or after training.
During training or competition the ultimate goal is to maintain a moderate to high level of blood glucose. If blood glucose begins to fall below the normal range of 80-100 mg/dl range, then the metabolism of energy (ATP) to meet the demands of the training will not be sufficient. Studies examining the effects of carbohydrate consumption on both mental and physical abilities have shown a reduced level of impairment when appropriate carbohydrates are consumed during exercise. This is applicable for both pre-season training, for peak performance over the course of a day, and competition, for peak performance over the course of several hours.
During activity the type of carbohydrates and amounts are important to optimize the effects of the feedings. Glucose or sucrose (table sugar), have both been shown to be effective in replenishing blood glucose levels during the event. However, glucose polymers (as seen in sports drinks) may have an advantage over the previous sugars in terms of absorption. By increasing the percentage of glucose polymers consumed (ie Gatorade, Powerade, etc.) one increases the carbohydrate content without increasing osmalality. Studies have also suggested that long-chain glucose polymer solutions are more readily used within skeletal muscle during exercise than are glucose or fructose. The amounts of carbohydrates ingested during training or competition are also of importance, as this will determine largely the increases in blood glucose concentrations. Research has been thoroughly conducted to determine the optimal timing of intakes and volumes consumed to maintain glucose levels in the body. The standards that have been adopted are to consume 150 to 200 mL (6-8 oz) of 5 to 7% glucose solution or polymers every 15 to 20 minutes. This value may not be as applicable during pre-season training due to the length of time practices are often held, in addition to the costs of providing the carbohydrate drinks. If sufficient energy is ingested in the hours prior to training, glycogen and carbohydrate stores should be saturated enough to sustain the work outputs during practice. This however, during pre-season is determined largely by the feedings that occur after or in between practices.
Post-training nutrition is vital to allow for optimal recovery of substrates (fuel) and repair of damaged tissues (muscle proteins). This feeding can be viewed in two parts: in the hour after training, and in the 2 to 3 hours after training. Within the hour after training it is important to elevate blood glucose and begin the synthesis of glycogen as soon as possible. It is optimal to consume simple or liquid carbohydrates within this time period, as rates of synthesis will increase due to faster gastric transit time and quicker absorption though the GI tract. Approximately 1 g/kg/bw of simple carbohydrates should be consumed within an hour, and an additional .8 to 1.0 g/kg/bw in the few hours afterward, combined with 20 to 30 g of quality protein. An example would be a 220 lb football player consuming 90 g of carbohydrates from a sports drink after training, followed by 80 to 100 g of simple/complex carbohydrates with 30 grams of protein within 2 or 3 hours. This may need to be altered depending on the pre-season practice schedule. A significant amount of calories should not be consumed within the hour before training, due to GI comfort of the athlete and possible hypoglycemia that can occur.
Post-Season
Training in the off-season is usually characterized by an increase in strength or power training, with a decrease in aerobic conditioning. This type of training results in a change of substrates used for fuel, but also the type of stimulus created on muscle physiology and metabolism, which produces a need for different recovery techniques with regards to nutrition. The strain placed on muscle tissue during resistance training is more localized and concentrated, and there is a greater breakdown of muscular proteins. The breakdown of glycogen for fuel may also be an important factor, which is determined by the work to rest ratios. Higher work rates with less time in between sets will cause a greater use of glucose to replenish ATP within skeletal muscle. The extent to which the muscle structures are damaged during training, in addition to the inflammatory responses, will determine the repair needed in the days following the training. It is therefore necessary to ensure an adequate and consistent intake of not only carbohydrates to restore glycogen levels, but also protein to assist in repairing damaged muscle fibers.
Within the hour after training it is optimal, as with pre-season or in-season training, to replenish glycogen stores completely with an intake of approximately 1 g/kg/bw. However, post-exercise protein intakes within the hour after strength training should be added additionally to begin the synthesis of muscle proteins as early as possible. Studies examining the effects of resistance training on intramuscular protein breakdown, characterized by leucine (BCAA) oxidation, have shown a significant increase in metabolism. This indicates an increased need for amino acids after training to replace the proteins lost. Additional supplementation of BCAA after training has been shown to enhance protein synthesis and recovery.
In conclusion, supplement requirements will change depending on the demand on the body during all cycles of periodization. With regards to carbohydrate consumption and daily timing of meals, similar practices can be followed as with pre-season or in-season nutrition, with particular attention being paid to recovery in the off-season, due to the increased physical demands placed locally on the body with resistance training. In terms of energy intakes (total Kcal), they can be altered to produce changes in body weights or composition. The standards adopted for increasing or decreasing body mass are to add or subtract approximately 500 Kcal per day with the athlete’s diet. This will help to produce gradual and quality changes in body composition (decreasing in fat mass while maintaining or increasing lean mass). Monitoring of the athlete’s feelings of fatigue should be monitored if total caloric intake is reduced. Insufficient energy may lead to decreased exercise performance or a possible increase in local inflammation. Uncontrolled inflammation may lead to possible soft-tissue injuries, and it is therefore advised to consult the advice of a qualified nutritionist prior to making any changes to an athlete’s dietary regimen. Download Paper
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