I thought I had posted something on this topic a while ago, but either I didn't, or somehow the post was deleted.
The original thought was this: perhaps Aristotle's exclusion of those who work in the mechanical arts from citizenship could be justified on his own premises. iirc, he claims that this sort of work is debilitating to the body. You may ask, if so, why should it hinder someone from exercising citizenship? After all, is not the soul or mind more important than the body to being a citizen? But I believe that Aristotle, like many of the ancient Greeks and Romans, believed that there was a connection between the soul and body, one that we do not take seriously these days, if we believe in the existence of the soul at all. Hence, "mens sana in corpore sano." If a healthy body is conducive to a healthy (or sound mind), then what of an unhealthy body?
If an unhealthy body leads to an unhealthy mind, and an unhealthy mind is opposed to the good exercise of citizenship, then it seems that any regular work that results in an unhealthy body is opposed to the good exercise of citizenship. And hence Aristotle's prohibition is justified on his own premises.
Even if we do not take this premise about the connection between mind and body seriously, we can consider that certain kinds of work (sitting 8 hours every day or more in front of a computer, for example) can lead to the acquisition of vice . It seems to me that sedentary work, especially when it is separated from a healthy diet and physical exercise, is not only conducive to bad health, but sloth and soft living as well. One could spend part of one's free time undoing the damage by going to the gym and so on, but this would not be a very integrated way of life, and leisure should be better spent on other activities. (One may not have much of a choice for that matter, but this does indicate who constricting the normal workday really is, and how poor wage slavery compares to the life of the medieval peasant.)
Also, those who have the endurance to go to the gym regularly may not have the full virtue of courage--just a shriveled counterfeit as it is centered only on a particular object that may not be praiseworthy (vanity, or excessive concern with one's appearance, for example). So it is possible that one may be "hard" with respect to one's chiseled physique, but nonetheless soft with respect to one's character.
If one believes in the unity of the virtues, then to be intemperate or soft can have an impact on one's practical reasoning and actions. If the good exercise of citizenship is dependent upon virtue, then those who do not have virtue should not be given citizenship, as they will use it poorly, to the detriment of themselves and others. "Mens sana in corpore sano" could be interpreted in the following manner: one should maintain a healthy, fit body in a virtuous manner, and a healthy, fit body serves as an aide to virtue by facilitating virtuous actions.
But maybe there is something to be said for the Greek and Roman understanding -- or any understanding of the health that is more holistic. (For example, an Asian understanding of health, despite its erroneous principle of qi.) Physical fitness may be important for our senses and brain to function well. Given the connectedness of the parts of the body, we cannot rule this possibility out a priori.
What of the practical implications for philosophers and academics? (Or those who sit behind a desk for much of the day?) What would Socrates, Plato, and Aristotle say about the lives of modern academics? How much sitting is really necessary for a learner and teacher of wisdom? Without the demands of publishing and modern "scholarship" put upon him, a philosopher could live a more balanced, active life. A philosopher studies not to know what so-and-so said, but to know the truth. This is also true of theologians.
(One could say that given their education, the intellectual growth of academics has already been stunted. Harming their mind due to lack of sufficient care for their body is a less serious problem.)
How about contemplatives and monks? Monks and other religious engaged in study do not, as far as I know, devote all of their waking hours to study. Of course time is set aside for the liturgy and prayer. Monks are expected also to contribute to the oikonomia of the monastery as well. (Though I suppose it may be the case that those who are exceptional are permitted to study as their economic task.)
I would think that the Dominicans are encouraged to take recreation after meals. While being abstemious prevents one from putting on too much weight, is it really a healthy solution for a lifestyle that could be too sedentary? I don't not know if there are any rules that explicitly mention physical fitness. Are measures to take care of one's health are assumed? Or is maintaining fitness and health something that the superior should take into consideration when assigning duties and work? Is the monastic life more balanced with respect to the good of the body? Or should a religious not be concerned with one's fitness?
I know that some of the laity may be scandalized, perhaps wrongly so, if they see a religious devoting what they consider to be too much time to maintaining their physical fitness. "Don't they have better things to do with their time?" Is God is bound to prevent us from harming ourselves through neglect, even if this is due to preoccupation with doing His work?
Can the Greek ideal of the virtuous man, who takes care of both body and soul, be harmonized with the Christian ideal of the saint? The easy answer is that all that is good is permissible, in moderation. But if a religious is not doing enough physical activity during the day, should he set aside some time for exercise everyday, or even be required to do so?
ST. DOMINIC and HIS WORK, by Pierre Mandonnet, O.P.