Reader Chih Hao Hsu sent a few days ago (2023-3-7) to:

"Hello Professor Lin: My family recently considered going to a locking gym to exercise. This home is more special. The equipment he uses is all oil-pressure equipment. Oil-pressure retraining equipment can only be trained to concentrate contract, but no center-pressure contraction. Contraction). I used to be enthusiastic about training, and my understanding of the principle of training is that retraction is a very important part, even necessary. To strengthen muscle strength, but for health, will the health benefits be greatly reduced without training without training? Thank you Professor. ”

First, the "oil pressure retraining equipment that this reader said can only be trained to centripetal contraction (concentric) Contraction, without eccentric contraction, and "removement is a very important period, even necessary", are all correct.

Then, why choose oil pressure retraining equipment?

muscle contraction is divided into two categories: isometric and isotonic. The name is sensible. When the muscles are reduced for a long time, the length of the muscle will not change. Relatively, when the sheets are contracted, the length of the muscle will increase or decrease. Therefore, the contraction of the waiting time is divided into two categories: concentric and eccentric. When centripetal contraction, muscles will shorten, and when centripetal contraction, muscles will grow.

Taking the example of calendering to strengthen the dentistry, the dentistry becomes shorter when the little arm moves upward, so it is a centripetal contraction, and when the little arm drops downward, the dentistry becomes longer, so it is a centripetal contraction. When the small arm is maintained at 90 degrees with the big arm, the length of the secondary muscle does not change, so it is a time-lapse contraction.

Take the example of lying forward to exercise the chest muscles. When the body is pressed down, the chest muscles become longer, so the heart is retracted, and when the body is erected upward, the chest muscles become shorter, so the heart is retracted. When the body is maintained in the middle of downward pressure, the length of the chest muscle does not change, so it is a time-lapse contraction.

For the importance of centricular retardation, please see the effects of eccentric versus concentric resistance training on muscle strength and mass in healthy adults: a systematic review with meta-analysis. Its abstract point is: "The strength growth after celiac training is more specific in terms of speed and retraction pattern than centripetal training. Centriac training performed at high strength has been proven to be more effective in promoting muscle mass increase measured by muscle circumference. In addition, , Centrifugal training also shows the trend of increasing muscle cross-sectional volume. ”

The most widely used remedial equipment, that is, traditional, such as calenders and metal block machines, can perform centripetal contraction, centrifugal contraction, and isometric contraction. However, oil-pressure-type heavy equipment can only undergo centripetal contraction muscle training. Take the machine that exercises the 2-head muscle as an example, there will be resistance when pulling up the grip, but there will be no resistance when putting it down. Take the machine that exercises the chest muscles as an example. There will be resistance when pushing the grip, but there will be no resistance when pulling back. Therefore, the health benefits of oil-pressure retraining equipment will be greatly reduced.

For why oil-pressure retraining equipment is needed, we will look at a research paper published in 2011, Effects of hydroulic-resistance exercise on strength and power in untrained healthy older adults. (Note 1: The hydro-resistance exercise in the title is literally translated as "hydraulic resistance exercise", but it is actually an oil-pressure retraining. Note 2: Although the strength and power in the title are all "power", the difference is that the latter is instantaneous power, so I translate it into "explosion force").

This paper says in the discussion: "The hydraulic resistance traction equipment does not provide resistance based on gravity and is designed so that if the movement suddenly stops, the load on the working muscles will end. In addition, the equipment does not return to the starting position immediately. These properties allow participants to stop at any time of movement without being damaged by moving the equipment or falling weight."

The conclusion of its digest is: "Hydraulic resistance exercise can significantly improve the strength and explosion of the elderly. Therefore, hydraulic resistance exercise is an effective form of resistance training that can provide low-strength and moderate-strength training for the elderly."

From these two paragraphs, it can be seen that since the oil pressure retraining is relatively gentle and does not cause harm, it is more suitable for the elderly, weak people, or people with special needs (such as rehabilitation) to train muscle strength. Readers who are interested in understanding how this type of machine works should read YouTube.

Reader Chih Hao Hsu has experience in traditional retraining and should be young, so of course there is no need to choose oil pressure retraining.

Original text: Oil pressure retraining equipment: can only exercise myocardial strength, so why should I choose

Responsible editor: Gu Zihuan