ILANA KATZ MS, RD, CSSD
Different activities require different energy, or metabolic, requirements on muscles and as a result, muscles necessitate different nutritional components when they work for speed, power, and/or endurance. A burst of energy, or high power and speed, over a short period of time are called anaerobic activities, which are almost entirely reliant upon glycogen (muscle carbohydrates) and phosphocreatine (source of energy for muscular contraction). Resistance training presents an obstacle in terms of balancing the anaerobic system with the aerobic system. The nutritional challenges for resistance training include the following: 1. The amount of energy required, 2. The specific breakdown of macronutrients (carbohydrates, protein, and fat) required for building lean muscle, 3. The timing of the specific nutrients with relation to the growth and the recovery periods and, 4. Hydration for workouts.
One of the most challenging aspects for endurance athletes is that depending on his or her current cycle of training, he or she will incorporate some resistance training into the endurance regimen for strength and stability purposes. This incorporation requires a balance of nutrition for resistance, as well as endurance.
Macronutrient Breakdown
The physiological system that stimulates muscle growth is hormonal, specifically growth hormone, insulin like growth factor (IGF), and testosterone. To optimize muscular hypertrophy, or growth, one must focus on nutrition that stimulates these hormones. Strength and power athletes, in particular, tend to require some additional energy to support their muscle growth. On average, an additional 500 calories (balanced between carbohydrates, fat, and protein) daily are needed to gain one pound of muscle mass per week.
Endurance athletes incorporating some weight training, on the other hand, may not necessarily want to build muscle mass and should instead focus on recovery of muscle glycogen. For the endurance athlete, no additional calories for building mass are required; however, carbohydrates are typically the limiting energy substrate, meaning that they will run out before protein or fat runs out. Glycogen depletion is a term used to describe when carbohydrates are used up and no longer exist as a fuel source for working muscles. When this depletion of carbohydrates occurs, the muscle’s energy stores are depleted, which can cause cell and muscle tissue damage as well as stress on the immune system is exercise continues. This means that these energy stores should be replenished before the next workout. Both power and endurance athletes seek out high quality, convenient supplements to aid in accomplishing these ends.
Rebuild and Recover
Remember that an anaerobic exercise, as mentioned previously, is dependant upon phosphocreatine, as well as glycogen and that an aerobic exercise is dependant upon glycogen and fat. An intense weight training session can deplete in excess of 30 percent of muscle glycogen stores. Thus when heavy resistance training is combined with endurance or cardiovascular training, muscle glycogen stores can become significantly depleted in a short period of time. A priority after your workout should be a nutritional recovery in order to prepare your muscles for the next bout of training. In order to prevent further stress muscles rebuild stronger and bigger fibers that are broken down during strength training.
A combination of carbohydrate and protein is the best source of macronutrients for post exercise recovery. Protein, being the major construction material utilized in muscle repair, is a large part of the recovery nutrition strategy, however, contrary to the myth that strength and power athletes should rely on protein, carbohydrates is what restores glycogen in muscles. With their scientifically engineered carbohydrate to protein ratio as well as their water and electrolyte content, many sports drinks are highly recommended for the recovery period due to their ability to absorb rapidly. Athletes who lift weights will undoubtedly have higher protein requirements than sedentary individuals. Not more than 0.8 grams of protein per kilogram of body weight is more than likely adequate for muscle repair and growth for the strength athlete 0.6 grams per kilogram of body weight for endurance, but for all athletes, carbohydrates should be the main nutrition source for recovery.
Timing your nutritional intake
Before
It is important to fuel muscles before the workout begins. Glycogen depletion is a term used to describe when carbohydrates are used up and no longer exist as a fuel source for working muscles. In other words energy stores are depleted, which can result in cells and muscle tissue being damaged and the immune system being stressed if exercise continues. Therefore, fill the glycogen tank by eating a meal comprising mostly carbohydrates two to three hours before exercise. For power athletes, some protein consumed prior to resistance training can contribute to and enhance muscle synthesis. Conveniently, there is a variety of high quality protein supplements on the market that are scientifically formulated with a good source of carbohydrates to delay glycogen depletion as well as enhance the recovery nutrition. Other easily digestible, high quality protein comes from food sources, such as milk and yogurt, soy products, tofu, poultry, and lean meats, and various protein powders such as whey, casein, soy and egg protein.
During
During resistance workouts, phosphocreatine in the muscle is the main fuel source, but remember that muscle glycogen can be a limiting factor (as it depletes) based on the intensity and duration of your training. Consuming a sports drink for the carbohydrate content should help maintain muscle glycogen stores and provide energy during the workout, while simultaneously aiding in hydration. Hydration through sports drinks should also be supplemented with water before and during the workout.
After
It is important to consume mainly carbohydrates and some protein immediately following a workout for recovery. The During this time there is a period known as the “muscle recovery window” or the “glycogen replacement window” (the first two hours after exercise). This time period occurs because the enzyme (glycogen synthase) responsible for storing glycogen is highly elevated instantly after exercise. Furthermore, after weight training, new muscle protein is being synthesized.
All athletes, overall nutritional recovery intake should include replenishment of calories burned during the training session. Scientific evidence for endurance athletes’ recovery has been found to be optimal at a 3-4 to 1 ratio of carbohydrates to protein in the meal immediately following the workout taking place over multiple hours. It is just as important for power and strength athletes, to eat a combination of carbohydrates and protein both before and after weight training as an ideal nutritional strategy for improving muscle building and growth. Although there is no formulated ratio of carbohydrates to protein for strength training as there is for endurance in the recovery meal, a 3-4 to 1 following an intense weight training session would certainly fulfill the key nutritional aspect of replenishing glycogen and aid with repair and rebuild of muscle.
Commercial sports supplements containing a mix of carbohydrate and protein are convenient and will generally meet these nutrition requirements. Other ideal carbohydrate and protein combinations include a protein shake made with whey powder and fruit, yogurt with fruit, a peanut butter and honey sandwich on whole wheat bread, or =low fat cheese and whole wheat crackers.
Although the exact protein requirements for varying athletes remains a much debated subject, most sports nutritionists agree that athletes need extra protein for optimum performance and recovery. Furthermore, power athletes, or athletes wanting to build muscle, may need slightly more protein than endurance athletes. On the other hand, endurance athletes will need more carbohydrates. While a high-protein diet provides an excess of the building blocks used to assemble muscle protein, unless there are sufficient carbohydrates present to support training, this protein will only be used to supplement the fuel supply. Carbohydrates, besides being the main muscle fuel, play a valuable role in muscle metabolism, particularly that of helping to conserve muscle tissue for both strength and endurance. All in all, a balance of carbohydrates and protein is key, no matter what your athletic focus is.
Guidelines for Best Sources and Amounts of Nutrients for Recovery
A generalized equation can be used to determine recovery requirements. From experience, most athletes need to consume 0.5 grams of carbohydrate per pound of body weight every two hours for six to eight hours after a workout. Therefore, if you are consuming 240 calories (60g) of carbohydrate after a work out, with the generalized ratio of 3:1 (cabs to protein), 80 calories (20g) of protein should also be consumed.
The calculation for a 150 pound athlete:
1) .5 grams of carbohydrate x 150 lbs. = 75 grams of carbohydrate needed for recovery
2) Multiply 75 grams x 4 (the number of calories in a gram of carbohydrate) = 300 calories of carbohydrate
3) If the recovery ratio of carbohydrate/protein is 3:1, then you need 100 calories of protein per 300 calories of carbohydrate. (100 calories divided by 4 (4 calories per gram) = 25 g of protein).
Athletes often rely on recovery nutrition in the form of liquid mixes. Carbohydrate to protein ratio are often formulated in the pre-made mixes for optimal recovery. Creating individualized recovery drinks requires experimentation with different types of carbohydrate and protein to determine which combination works best.
If you prefer to refuel with solid food, here are some good options:
- Half whole wheat bagel with ¼ cup cottage cheese or 1 tbsp peanut butter
- Yogurt smoothie, berries and a tablespoon of protein powder
- Medium sweet potato and 2 egg whites
- Small turkey sandwich on whole wheat bread
- Bran cereal with skim milk and a few nuts
- Protein bars (many specially formulated with optimal carbs and protein)
References:
ACSM Position Statement: Nutrition and Athletic Performance. Med Sci Sports Exerc 2000; 32(12):2130-2145.
Nancy Clark. (2003). Nancy Clark’s Sports Nutritionist Guidebook, Third Edition.
Advances in Sports Nutrition. Journal of American Medical Association. JAMA 2003; 289: 1837-1850.
