Many people associate the idiom no pain no gain with the world of exercise and body building. Indeed, exercise gurus often used this expression or "feel the burn" during their routines as motivation for their students. Exercise programs, such as high intensity aerobic workouts or weightlifting circuits, were not considered effective unless the participant's muscles reached a painful stage of near-failure. The gains in muscle mass or cardiovascular strength would only come after the pain of intense exercise.
In truth, the expression can be traced back to at least 1650, with a two-line English poem extolling the virtues of self-sacrifice for greater spiritual gain. Benjamin Franklin also alluded to "no gains without pains" in his Poor Richard's book entitled The Way To Wealth. The idiom implies any quest for improvement that does not involve some level of pain or sacrifice is most likely not a noble quest. If a person is not willing to endure some difficulty, then he or she should not benefit unfairly from the rewards.
The concept of "no pain no gain" in the exercise and bodybuilding world has come under significant scrutiny in recent years. Some studies suggest that exercising muscle tissue to the point of pain or failure does not necessarily result in a gain in overall muscle mass. In fact, the damage caused by overworking or straining a muscle group can be greater than any perceived gain in mass or definition. A number of professional trainers now advise their clients to stop performing an exercise if they begin to experience significant pain.
As an idiom for life in general, however, many people still ascribe to the idea. Anything worth attaining in life, whether it be a promotion at work or a personal milestone, should be the result of hard work and sacrifice. Cutting corners or cheating to attain the same result should be viewed as dishonest or dishonorable. The mantra of "no pain no gain" often motivates people to work through difficult situations or keep their focus on a higher purpose. Not all gains necessarily require pains, but few things in life are ever attained through disinterest or passivity.