1 | is not conducive to beginners to develop good action patterns.
For beginners who want to start fitness, the most important thing is to master the basic action patterns, including squatting, pushing, pulling and hip flexion. They are the basis of strength training. Only by mastering them can you "use" your body better.
However, if you train on Smith machine, the fixed trajectory limits the exertion of your body, and your body can only move according to the trajectory, often unable to make correct action patterns.
Take squat as an example. Many people feel uncomfortable when doing Smith squats, and it is easy to hurt their backs and knees after practicing. This is all the oppression caused by the mismatch between Smith slide rail and your body structure and limb movements. In order to avoid this oppression, people often "lean" on the barbell to do Smith squats.
In this case, the center of gravity of the barbell runs to the back of the body and does not coincide with the center of gravity of the body, which not only fails to achieve the training effect of squat, but also is difficult to ensure safety. More importantly, this is obviously an unreasonable mode of action.
I often emphasize to students in class that the center of gravity is the core of strength training. The ability to control the center of gravity is also the ability that beginners must learn first. However, the Smith frame makes you lose your center of gravity.
If you don't rely on the barbell to do the action, will Smith's barbell center of gravity coincide with his own body center of gravity as much as possible? It's also difficult! Because even if the top experts do squats, the trajectory of barbell rise and fall can't be an absolute straight line. But Smith's trajectory forces the barbell to walk in a straight line, which will make you uncomfortable when you squat. Different people have different body structures, which may also put extra pressure on the waist and knees.
Remember, in training, people should actively control the trajectory of barbells, rather than barbells determining people's posture.
2 | Smith machine can't exercise physical stability.
Almost all the heavy objects we encounter in our life have no fixed trajectory, and most of them belong to free weight. For example, changing a bucket of mineral water, giving my girlfriend a princess hug, and steadily lifting the child ... This requires not only a good grasp of the center of gravity, but also a strong physical stability, which will balance our bodies and coordinate our efforts.
The trajectory of Smith machine can help you solve the stability problem, without exerting your body's stability ability at all. Novice squats with Smith machine are often like this: hanging barbell pieces, shouldering, pushing up, done! It doesn't matter whether the force is symmetrical or not, you can stand up if you stand crooked! At this time, squatting seems to be relatively simple on the surface, and you may fall into the misunderstanding that "I will succeed as long as I push the bar up".
There are two kinds of muscles in our body, one is superficial action muscle and the other is deep stability muscle. Stabilizing muscles is very important for our athletic ability. Strong stabilizing muscles and strong body control ability will also reduce the probability of sports injuries. With Smith machine training, under the "escort" of the track, you can only exercise the action muscles, but not the deep and stable muscles.
This can also explain why many students can easily squat 50-60kg on the Smith machine and squat 20kg with a free barbell.