Physical loads and protein requirements

Last reviewed by: Aleksey Portnov , medical expert, on 15.05.2018

Studies show that the protein requirements during exercise are greater by 0.8 kg per day than the recommended dietary norms developed.

Endurance Load

The stress on endurance causes a training adaptation, which changes the metabolism of proteins. The increased oxidation of amino acids increases the protein content of the mitochondria, which may require more proteins than recommended dietary norms (RDN). The intensity of the load and the duration of training contribute to the enhancement of oxidation of amino acids. This can help identify hardy athletes participating in training sessions of varying intensity, since their need for proteins is different.

  • Low intensity. Athletes who regularly train at V02max below 50% (leisurely walking, bicycle race, dance) do not need additional protein. Indeed, such a level of loading can give a positive incentive for protein utilization, without increasing the body's need for it.
  • High intensity. Athletes who regularly and vigorously exercise (running, swimming, cycling) require more protein than RDN - from 1.2 to 1.4 g-kg per day (140-160% RDN). It is assumed that such an increased demand for proteins is most important during the first two weeks of the intensive exercise program.

Load to overcome resistance

Lifting weights increases the protein requirements. Maintaining muscle mass requires significantly less protein than its increase. Studies show that with adequate energy absorption, muscle mass can be maintained at a protein intake level of 5-10 g-kg per day. However, bodybuilders and weightlifters rarely want only to preserve the available muscle mass. Most of them try to increase it with the help of training classes.

Existing recommendations for building muscle mass during resistance training are in the range of protein intake of 1.4-1.8 g-kg per day (160-200% RDN). Adequate energy consumption also helps improve protein utilization while increasing muscle mass. Energy should be adequate or even slightly higher than the energy needed to maintain body weight (200 kcal per day or 3 kcal / kg per day).

Timing for protein intake

Studies have shown that some protein and carbohydrates (the recommended ratio of 1: 3) after physical exertion contributes to the enhancement of glycogen resynthesis, stimulating the release of insulin. The combination of proteins and carbohydrates in food after intense training can also stimulate an increase in muscle mass by releasing insulin and growth hormone. It has been suggested that the carbohydrate supplement, immediately or within 1 h after the resistance load, gives a more positive nitrogen balance than a few hours after the load.

An important subject for discussion is improving the methodology of training sessions. Training to overcome resistance and training for endurance rarely exclude each other. Bodybuilders and weightlifters participate in aerobic exercise, but not at the level with athletes working for endurance. The latter recognize the benefits of training sessions with lifting weights. Since many athletes are engaged in training to develop strength and endurance, their protein requirement is 1.2-1.8 g-kg per day. The requirement of each athlete in the protein must be calculated individually.

Calculation of protein requirements

The need for a protein can be determined by identifying the level of motor activity for different groups of people. It is important to consider, the athlete begins to train under an individual program and / or he or she is already involved in training sessions for the development of strength and endurance. So, a football player who regularly trains for endurance and strength development, the need for protein will be maximum, and for other athletes who perform only aerobic loads without lifting weights, the protein requirement may correspond to the lowest level.

It is important to know!

Urea excretion in urine is proportional to the protein content in the diet, as well as the metabolic rate of endogenous proteins. Read more..

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