The New York Times' Well section has reassuring news for anyone hitting the gym and not seeing results. Many researchers agree that muscle size and definition are not as important to your long-term health as those muscles' endurance and strength, which prevent atrophy and weakness in old age:
To maintain endurance, you should engage in activities that pump blood to the muscles, like walking. For strength, you need to lift weights, concentrating on what Professor Fitts calls the antigravity muscles, those of the back and legs. And, he adds, you should also maintain arm strength.
While there's nothing wrong with having a beach-worthy set of abs or biceps, the article notes that genetics, and gender, may prevent many from doing real sculpting, so it's better to make sure those muscles actually work. Photo by pecdec200.