Whenever you hear the phrase "no pain, no gain" don't you just want to throw up on the person that said it to you? Unfortunately its been etched into the minds of many people in the fitness world that have this notion that in order to get what you want, you go through some kind of torture and "pleasurable" pain. I'm sorry but if you need pain to get results you're either sadistic or just plain full of brain farts. True exercise is suppose to help heal and build, not be painful and torturous.
For most people, they need to understand that building muscle & training the body in general does take effort but it certainly should never be painful; discomfort is one thing I'll take that but pain is just plain dumb. When I was getting back on my feet, I used exercise to heal my body and built on developing great blood flow into the muscles themselves. Some exercises are very tough and can be crazy to work up to but don't ever believe that pain is going to get you somewhere, it can and its called Misery and i'm not talking the Kathy Bates kind either.
I still to this day train to stay healthy both inside and out, I've gotten back into doing the healing exercises called DVR's (Dynamic Visualized Resistance) which are done by tensing the muscles than moving throughout a range of motion in full fashion. Think of it as if you're driving with the brakes on. This type of training alone can be beneficial in how you energize the body, increase blood flow into the muscles down to the smallest capillaries & developing natural muscular definition. This isn't to build massive muscles like in bodybuilding but they can be used to develop the body's natural musculature and create healing strength and promote healthy flexibility in the shoulders, back, chest, thighs, calves & upper/lower arms. Even the Abs get an amazing workout because of the contraction using an exercise throughout the entire range of motion. No you won't be able to lift massive amounts of weights but because of the control you have to tense & relax the muscles it can certainly help if you're a weightlifter. What it truly does that it helps the muscles and tendons create an expansion of the range of motion in particular movements, basically another version of Muscle Control.
DVR's aren't necessarily new but have been used in various ways throughout the centuries in Yoga, Martial Arts, Bodybuilding & many other ways. The main component is not just to tense the muscles but truly connect through the mind/muscle concept where you think into the muscles. This type of training can be very taxing if you overdo it but with correct tension you can strengthen the body from the inside out. One of things they truly can do is put you in a state of pure blissfulness and mellow you out with pure peacefulness. Give them a shot. Its worth it.