Do you mean, working four days a week and having a three-day weekend?
I think that yes, that would be a big benefit for a lot of people. Much of peoples' time at work is wasted anyways... focusing work on four days and having three days for yourself and family would probably make people much happier and productive :)
First, I would like to give you a more correct way to ask the excellent question: If you were given a week with Friday, Saturday, and Sunday free, would your efficiency also increase?
The answer: It depends! Some people will not be efficient no matter what kind of situation they are in. This could be to the way their brain is hardwired or because of human weakness, lack of skills, lack of focus, not enjoying the work, depression, etc., etc.
I have worked most of my life part time. When I do my paid work, I do it well. But on the off days, I do volunteer work and have learned to speak some Russian, speak Spanish as fluently as a native, have helped a few families change their lives and have raised four children. I am currently learning Chinese. So if you use your off time for a good purpose, then you may be more productive at work.
However, there are many people who sit around playing video games or some other type of activity that will leave them mentally exhausted and dissatisfied with life. You will not then be more productive at work. It really depends on how you use your time!
At first, thanks for your interpretation, 蔡雅馨
" If you were given a week with Friday, Saturday, and Sunday free, would your efficiency also increase?"
Not all the case in general, I consider that has to rely heavily on what type of work I am working on. If the work assigned by my supervisor has to be done by the end of the weekdays with no clear deadline, I would prefer to choose this mode of work so that I can really ensure that I can be totally free by the end of the week.
However, if the work requires high concentration and attention to go through over a long term, I would prefer I may arrange my holidays as I wish for and what I need to do is to complete the task within the time frame by the deadline. I may be clearly aware of when I can get rest once I finish my work.
As a whole, there is single rule that may fit all. You may choose your favored one according to your work style and your personal preference for leisure.