Since I started working in agriculture, I've met a great deal of farmers. On of the farmers I've worked closely with called farming "nature's gym." He, like many farmers who practice labor-intensive small scale agriculture, was about as fit as many elite athletes I know. This contrasts with the larger farmers I know, who are easier picked out because...well they are much larger.
Underscores the fact that while "saving" labor is economically efficient, there are costs and benefits that aren't often factored in. Most farmers labor much less than their counterparts in the past, but perhaps they pay for it in terms of health problems.
Last week I worked on his farm and while my muscles may be uneven (it's much harder to hoe with my puny left arm), they sure are large. The other farmer, a woman, told me that just like any sport, it's important to have good technique on the farm if you want to prevent injuries.
I say this because I find it interesting that so many people spend hours and hours in smelly boring gyms...when they could get a garden instead. I personally have shied away from gyms after I realized that the cleaning chemicals many gyms use seem to bother my lungs. I've felt much better since I've stopped going.
Small farms should market "exercise agri-tourism" or something. Suburbanites get skinny, farmers get free labor.