What is the problem with this? In high school, they had a universal gym that did not have the capacity needed and I would have a couple of guys get on the gym to add weight so I could work out. Did nothing but good for me and I am sure if they did not feel they wanted to, I would have said nothing but just looked for some other way or someone else. Some use milk jugs, cans of food, etc., whatever is available, so I see nothing wrong with using volunteers to help build health.