If you don't exercise, your muscle strength will decline. Just move and you can recover.

In the past year, have you noticed that friends who don’t usually exercise have started sharing their running routes or information about running events they have participated in on Facebook? It seems like all my friends around me have started to join in this road running feast.

“Huh… I only ran 2 kilometers, why are my legs so sore and weak!” said a friend who wanted to participate in his first road running event!

"You don't have enough muscles. You don't move much normally, right? Keep practicing and things will be different! 』

The above conversation took place last week between me and a friend. At this moment, it suddenly occurred to me, what would happen if those of us who do little exercise went even further and did nothing?

There is such a related study in the Journal of Rehabilitation Medicine. The study recruited 17 healthy young people (average age 23) and 15 healthy elderly people (all 68 years old) to conduct this experiment. The method is to fix one of the participants' feet and restrict the activity of that foot for two weeks. Afterwards, rehabilitation training was arranged for 6 weeks to observe the changes in the participants' muscle strength and lean tissue.

The researchers measured participants' strength (maximal voluntary contraction, MVC), leg endurance (Wmax), leg lean mass, and muscle mass before and after immobilization and at three and six weeks of rehabilitation.

After two weeks of fixation, muscle strength declined significantly

After the fixed test period, the measurement results showed that the strength of young people and the elderly decreased by an average of 28% and 23% respectively, and the endurance decreased by 13% and 9% respectively.

During rehabilitation, participants cycled 3-4 times per week and combined this with strength training. Compared with two weeks after the foot was fixed, the young people's muscle strength increased by an average of 34%, while the older people increased by 17%; in terms of endurance, the young people increased by 33% and the older people increased by 20%. (PS: Comparing the differences between young people and old people, after rehabilitation, young people can recover and even exceed their original levels; but the old people, although they have increased, have not returned to their original levels.)

Why do older people decline less?

As people age, their muscle mass decreases. In this experiment, the older people already had less muscle than the younger people, so when they declined, they naturally did not have as much muscle to lose as the young people.

The changes in lean tissue are noteworthy. After two weeks of fixation, only 485 grams of lean tissue was observed to be reduced in the young people; during the rehabilitation period, in the third week, the lean tissue of the young people almost returned to the original level, and in the sixth week, the lean tissue increased by 669 grams. (The results here are quite interesting. Perhaps it can be said that the lean body mass of the elderly is already low enough, so there is not much room for reduction.)

Source:

Vigelsø, A., Gram, M., Wiuff, C., Andersen, JL, Helge, JW, & Dela, F. (2015). Six Weeks' Aerobic Retraining After Two Weeks' Immobilization Restores Leg Lean Mass and Aerobic Capacity But Does Not Fully Rehabilitate Leg Strength in Young and Older Men. Journal of rehabilitation medicine, 47(6), 552-560.

This article comes from: Nutrition

Nutrition