Back in the era of the golden era of bodybuilding, athletes empirically established that different rep ranges are needed to train different muscle groups.

So, Arnold Schwarzenegger in his famous three-volume Encyclopedia of Modern Bodybuilding (Physical Culture and Sport Publishing House, 1993), co-authored with Bill Dobbins, names the following numbers: 8-12 repetitions for the upper body and 12-15 for legs, “… and perform each set” to failure “- until the muscles become unable to do at least one more repetition.”

There will always be exceptions to the rule, but for most people, these numbers will turn out to be true, because they are confirmed by modern science. Why do you need to do more repetitions for the legs than, for example, for the arms? But because a person throughout his life moves with the help of his legs, using the muscles of the lower leg and thighs. Walking is a low-intensity exercise that does not require much effort, so it is carried out with the help of slow fibers.

Even running at an average speed occurs almost exclusively due to these fibers. In the process of evolution, the human muscle composition was formed in such a way that the muscles of the lower half of the body are 50% slow fibers, and, for example, the arms – only 30%. Walking and slow running do not cause the formation of lactic acid in muscle fibers and therefore do not contribute to their hypertrophy.

Slow muscle fibers are saturated with mitochondria to the limit, and the more mitochondria in muscle fibers, the more difficult it is to acidify them with lactic acid, since mitochondria convert lactic acid into neutral carbon dioxide and water with the release of energy, which is necessary to continue movement. In addition, even some of the fast fibers in the muscles of the legs have mitochondria, although they are not as numerous as in the slow ones, nevertheless they also have the ability to utilize lactic acid. That’s why our legs and calves are so hardy. A person can walk many kilometers without stopping.

Try to walk for the same long time on your hands, and even if your partner holds your legs, after a few tens of meters your hands will “clog”. By the way, even different muscles of the thighs have different endurance, for example, the muscles of the back of the thigh are more resilient than the muscles of the front, because when walking, it is the back that works, and the front only when walking up the stairs.

An untrained person will acidify much faster when climbing stairs than when running at an average speed, although the load on the muscles is about the same. This determines the features of effective training of the muscles of the lower half of the body. In order for muscle fibers with mitochondria to acidify during strength exercises (and this is a prerequisite for subsequent hypertrophy), it is necessary that the rate of formation of lactic acid in them exceeds the rate of its utilization, and for this the approach should at least last a long time.

High-weight, low-rep sets are ineffective for hypertrophy of the lower body muscles. Consider this using the example of training the calf muscles. Let’s say an athlete performs 15 repetitions of calf raises while standing in the simulator, making small stops at the top point. The amplitude of movement in this exercise, as in any other calf exercise, is very small and amounts to 15–20 cm, the duration of each repetition is one to one and a half seconds. The total time the muscle is under load is 15–22.5 seconds. This time, of course, is not enough to maximally stimulate muscle fibers that have mitochondria (the so-called intermediate and oxidative type), which are very numerous in calves.

The approach must end in at least 30 seconds. To do this, either increase the number of repetitions to 20-30, or the duration of each repetition, for example, holding the weight for one to two seconds at the point of peak contraction. The weight of the projectile should be 60-70% of the maximum. The number of working approaches is four to five, rest between sets is at least five minutes. In between, you can perform exercises for other muscle groups.

Thus, the calf muscles will receive maximum stimulation. As mentioned above, 50% of the muscle fibers in the lower half of the body are slow, and, accordingly, the other 50% are fast. So, a fairly large part of the fast fibers of the calf muscles are intermediate, but the slow fibers are almost exclusively oxidative. Training of intermediate fibers gives faster and more visible results in hypertrophy. The example above illustrates just such a workout, but given the large proportion of oxidative (slow) fibers in calf volume, they should also be paid attention to.

For optimal stimulation hypertrophy of oxidative fibers, a different mode of loading should be applied. The main condition is to perform the exercise without relaxing the trained muscles (without stopping at the beginning and end of the movement). In this case, tense muscle fibers pinch the capillaries and cause circulatory arrest. Violation of blood circulation leads to fiber hypoxia, thereby intensifying anaerobic glycolysis in slow muscle fibers, lactic acid accumulates in them.

Any stop or relaxation of the muscle in the course of the approach reduces the effectiveness of the training effect. The weight of the projectile should be 30–70% of the maximum, the number of repetitions does not matter, it is only important that the failure occurs in the interval of 30–60 seconds of continuous work and is caused by a strong burning sensation in the muscles. Because of this much rest, it’s a good idea to insert calf sets in between sets of other muscle groups, such as chest, shoulders, or arms. It is not recommended to reduce the rest time, as this will increase the catabolism caused by the accumulation of hydrogen ions, which will slow down progress.

For more effective development of calves during the week, two workouts of the calf muscles can be carried out: one aimed at the development of intermediate fibers, the other – oxidative ones. The interval between them is three to four days. In this case, you can use a single exercise that you feel good about, or alternate two exercises with each other: one day one, the other another. As for the training of the soleus muscle, which is located under the calf, it does not play a big role in increasing the volume of the calves, and it can be neglected by athletes of the initial and advanced level.

Exercises for the calf muscles: lifting on toes, standing with a dumbbell in hand; lifting on toes, standing in a special simulator or in a simulator for hack squats; sock press in a leg press machine.
Exercise for the soleus muscle: lifting socks while sitting in a special simulator.

Approximate scheme of the weekly split

• Monday: legs
• Tuesday: chest, calves (intermediate fibers)
• Wednesday: rest
• Thursday: back
• Friday: shoulders
• Saturday: arms, calves (oxidative fibers)
• Sunday: rest

➜ Did you know that…

One of the clearest examples of the fact that the lower limbs contain different muscle composition is chicken, or rather chicken meat. We all know that chicken legs are red meat, while breast and back are white. The chicken, unlike wild birds, moves in space with the help of its legs, it almost always walks, sometimes makes short runs and only in exceptional cases takes off, but literally for a few seconds. Long walking, as already mentioned, is carried out with the help of slow muscle fibers saturated with mitochondria.

Mitochondria are the energy stations of cells, which, in the absence of intense physical exertion, oxidize glucose and fatty acids with the help of oxygen, forming energy from them. To transfer oxygen from the cell surface to the mitochondria, there is a special protein – myoglobin, in its own way it is an analogue of hemoglobin and performs the same transport role. Like hemoglobin, it is red in color. In those muscle fibers, where there are many mitochondria, there is also a lot of myoglobin serving them. Therefore, muscle fibers acquire a reddish color.

Well, that’s the reason why chicken legs are red: they’re made up mostly of slow fibers, because they’re more important to the chicken’s homely, slow-paced “lifestyle.” And the same breast consists of fast fibers that do not have mitochondria, which are glycolytic in terms of oxidative potential, and white in color. From this it is clear why the chicken cannot fly for a long time: the muscles that provide the flapping of the wings are very powerful, capable of tearing the weight of the chicken disproportionate to the size of the wings from the ground, but due to the lack of mitochondria, they are extremely unendurable: they quickly acidify with lactic acid and they fail.