Low-intensity aerobic, short-time aerobic, protein energy supply ratio is very small. High-intensity long-term aerobic, protein energy supply ratio is relatively large. In other words, running can't lose muscle, which is related to running intensity. Run slowly, run less for a while, and consume little muscle.

How slow should I run? This varies from person to person, because everyone has different aerobic exercise ability. Generally speaking, the speed is 8- 10 km, and the muscle consumption is acceptable within half an hour.

Long-term high-intensity running will definitely affect muscle gain, and it is possible that the muscles you train can't keep up with the muscles you lose. In addition to a large number of muscle decomposition and oxidation to provide energy, there is a more important reason, that is, high-intensity long-term aerobic exercise will cause type 2 muscle fiber atrophy.

Let me focus on this problem.

Muscle fibers can be divided into 1 type and 2 type. Simply put, the former is slow muscle fiber and the latter is fast muscle fiber.

Slow muscle fiber has rich capillaries, high mitochondrial density and strong ability to oxidize energy substances, which is suitable for long-term low-intensity repeated contraction. Aerobic exercise is mainly to mobilize slow muscle fibers.

However, fast muscle fiber has weak aerobic oxidation ability and strong anaerobic glycolysis ability, which is suitable for anaerobic exercise with short duration and large contractility.

It is found that after long-term high-intensity and long-term aerobic exercise, 1 type muscle fibers will increase and type 2 muscle fibers will shrink obviously. This belongs to the exercise adaptation of the body, and 1 type muscle fiber is added to improve the high-intensity aerobic capacity. However, in aerobic exercise, type 2 muscle fibers are basically not mobilized and become a burden, but will consume valuable energy in vain. Therefore, the body will partially decompose type 2 muscle fibers to fully adapt to aerobic exercise.

But when we practice muscles, we mainly increase type 2 muscle fibers, which is also a kind of exercise adaptation. If you aim at strength training, but do a lot of high-intensity aerobic exercise for a long time at the same time, then your muscles are likely to shrink to varying degrees.

Therefore, high-intensity long-term aerobic exercise, including running, cycling, swimming and other sports, has a negative impact on muscle growth. In addition to the consumption of muscles by exercise itself, aerobic exercise adaptation will directly cause the atrophy of fast muscle fibers.

So some people think that you are not afraid of running. Eating more BCAA before running can protect your muscles. This view is wrong. Whether BCAA can reduce the oxidation of muscle protein is still a question in itself. Even if it can, BCAA can't prevent the rapid muscle fiber atrophy caused by aerobic exercise adaptation.