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Extension of the legs in the simulator

The machine leg extension is an isolated exercise designed to develop leg muscles. The front of the thigh, the so-called quadriceps, is mainly involved. Its development will give your legs excellent shape and help you perform difficult basic exercises. Such as STAND LINK, SHOULDER SITTINGS, or FRONT. Leg extension has always been very popular. Of course, the simulators used to be a little worse, but the principle of execution was the same. Now, with the popularization of a healthy lifestyle, gyms are developing very rapidly. They come up with new directions like CrossFit

But most importantly, simulators are being modernized, which makes it possible to perform exercises more comfortably. But still, the execution technique has not changed and remained a very important component. Starting from setting up the simulator and ending with the movement itself. We will analyze all this in this article, then you yourself will decide whether it is worth doing this exercise. leg curl in the simulator

What muscles does leg extension use in the machine? 

This is a very large muscle group with 4 separate heads. Hence its name. From Latin “Quadro” is translated as four. Its more scientific name is the four main thigh muscle. Each of the heads of the quadriceps has its own name. 

  • Rectus muscle (head). It is the largest of the 4 heads. Located almost in the center of the thigh. It is superficial, so with a good development of this head, we can see it well. It is she who will give volume to the quadriceps, that is, its thickness. Its main functions include an extension of the lower leg (legs) and flexion of the hip (for example, when we sit down). Most of the load is received at the beginning of the movement. 
  • Broad medial muscle. It is a much smaller muscle. Located just above the knee, closer to the inside. Its shape resembles a drop of water. Responsible for the extension of the lower leg. 
  • Lateral broad muscles. Located on the front of the thigh, closer to the outer edge. Responsible for the extension and turn of the shins outward. That is feet apart. 
  • Broad intermediate muscle. This head is located under the rectus muscle. It is also responsible for leg extension and hip flexion. Her good development will begin to push the rectus muscle upward, thereby visually making your hips more massive. 

All of these muscles are attached to the thigh bone and are one of the stabilizers of the legs and knee. 

You can also identify some of the muscles of the assistants, which receive an indirect load and more serve to maintain the stability of our body position. 

  • Back muscles
  • Hand
  • Press

They work in static voltage. 

The advantages and disadvantages of this exercise

It may seem that since the exercise is popular and is advised by many, then it should have only one plus. Yes, I agree they are and this:

  • The ability to detail the quads and give them an expressive shape. 
  • The ability to finish off the quadriceps if there is no longer any strength left for heavy basic exercises. 
  • With the right technique, an extension can strengthen the knee ligaments. 
  • And of course, it provides isolated work on all 4 quadriceps muscles. 

But in addition to all these advantages, it must be borne in mind that this exercise is extremely traumatic for your knees! Cruciate ligaments are especially at risk.

They prevent the knee joint from moving forward and backward as well as inward and outward. That is, during a strong extension of the knee with a fixed pelvis (which happens in this exercise), these ligaments are very strongly stretched. More precisely, one of them in front. This can lead to its rupture. Yes, it can be treated, but for me, it’s not worth it. And after such an operation, you are unlikely to be able to continue your workouts at the same intensity. Especially for beginners, this exercise has no definite meaning. After all, you cannot build muscle mass with the help of extensions! Why am I telling you all this? Because it is very important for me that you have an understanding and are aware of all the risks before proceeding with the leg extension in the machine. And knowing this, you will already decide whether it is worth exposing your knees to such danger at all. 

Still, exercise can bring not only injury but also benefit. The main thing is to know when to do it and not make gross mistakes. The most important thing is to do everything with the right technique.

Execution technique 

From the outside, it may seem that the exercise is very easy to perform. I sat down on the simulator and began to unbend and bend my legs. But unfortunately, it only seems so. Some technical issues and subtleties must be taken into account. And before starting the exercise. We will need to customize the simulator for ourselves.

Starting position:

The leg extension machine resembles a chair. It has an adjustable backrest that moves back and forth. Special soft foot cushion. It is also regulated, thereby rising higher or lower. To prevent the basin from coming off the seat, handles are made on the sides. For which you have to hold on with your hands. The weight setting system is different. From barbell pancakes to special blocks. 

  • Walk up to the leg extension machine. Set the weight you need by hanging the pancakes or setting the limiter to the required number of blocks. 
  • Adjust the backrest so that your thigh is fully resting on the seat. And the knee extended slightly beyond the edge of the seat. 
  • Slide your feet under the roller. It needs to be adjusted so that it is located in the lower part of the lower leg, in the ankle joint. In this case, the legs should be bent at an angle of 90 ° or slightly stronger.  
  • Next, we straighten our back and bring the shoulder blades together. We rest against the back, and with our hands, we grab the handles. 

Important! The knee should not have an acute angle when bent. This will only increase the stress on the joints. And there will be a risk of injury! 


  • After taking the starting position, as you exhale, straighten your legs at the knee joint. 
  • Do not pause at the high point. As you inhale, bend your legs to the starting position. 

Why I do not advise to stay in the top position. Everything again rests on keeping your knees healthy. Yes, if we pause briefly at the top, our quads will get a lot of loads. But it will also affect the joints. Therefore, it is worth choosing health or efficiency. 


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