Strategies are laid out for both endurance, muscular (resistance) work outs, or both

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, and 3. The timing of the specific nutrients with relation to the growth and the recovery periods.

As a reminder, since it is not covered in detail in this article, hydration plays a major role for all recovery. Rule of thumb is to remain hydrated consistently, start any work out off hydrated, continue to hydrate during the work out, and replenish any losses post work out.

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. Contrary to the myth that strength and power athletes should rely on protein as a major source of fuel, the balance of calories should come from carbohydrates, fats, and protein. On average, an additional 500 calories 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.

Protein, being the major construction material utilized in muscle repair, is a large part of the recovery nutrition strategy. Athletes who lift weights will undoubtedly have higher protein requirements than sedentary individuals. 1.2 grams per kilogram of body weight is more than likely adequate for muscle repair and growth for the strength athlete. For the endurance athlete. One gram per kilogram of body weight should be adequate for muscle repair. A combination of carbohydrate and protein is the best source of macronutrients for post exercise recovery. With their scientifically engineered protein to carbohydrate 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.

Timing your nutritional intake

Before

For power athletes, the protein consumed prior to resistance training (combined with some carbohydrates for glycogen maintenance) can contribute to and enhance muscle synthesis. Essential amino acids, which come from high quality proteins such as skim milk, whey protein, and protein from animal foods are the most potent stimulators of muscle protein synthesis. Conveniently, there is a variety of high quality protein supplements on the market that can be incorporated before weight training, as well as for the recovery nutrition.

Some recommendations on these high quality supplements include:

Whey: A high quality protein extracted from the cheese production process that is easy to digest and lactose free in its isolate form.

Casein: Similar to whey and also extracted from dairy but may not have as complete of an amino acid profile as  whey. Casein is preferable for when the metabolism is slowing down for the day (before bedtime,) since it has a slower metabolic digestion rate than whey.

Egg Protein: Obtained from egg whites and is very high quality. It is known as the reference standard of which to compare other proteins; therefore, it is of the highest quality, but not as easy to digest.

 Soy: An easily digestible, high quality protein that is ideal for vegetarian athletes.

Vegan proteins: There are a number of vegan sources of protein available, such as hemp and pea protein.

High quality, easily digestible protein can also be obtained from food sources, such as milk and yogurt, soy products, tofu, poultry, and lean meats. Protein derived from animal sources has the most desirable range of amino acids to provide the highest quality. Plant protein and soybeans do provide some amino acids, however these must be properly combined with one another to receive the full amino acid range for a high quality protein source. For example, combining a legume with a grain, would provide a more quality protein than by either eating a legume (such as beans, lentils, edamame) on its own, or the grain (such as rice, cereal, barley) on its own. While the supplements mentioned above provide a convenient alternative, they must not be viewed as replacements for food.

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 can 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.

For endurance athletes, stick to the fast burning carbs before an aerobic work out, since the higher protein and fat can delay digestion, and increase the risk of gastric stress once the heart rate is high.

After

For both endurance and resistance, it is important to consume recovery carbohydrates and protein immediately following a workout. 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.

Summary

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.