The warriors emerge from their homes on the weekend, garbed in sweats and sneakers, a baseball cap worn just so. They sip high-caloric lattes and nibble on low-carb muffins, glancing at the paper once or twice before discarding it. They look as if they're about to take motion -- but don't.

And, as it turns out, these poseurs might just have the right idea, scientists said this week.

As millions exercise to maintain aging muscles, researchers at Loughborough University in the United Kingdom disputed conventional wisdom about the benefits of rigorous physical activity for all. One-quarter of people cannot simply grow muscle mass simply by exercising, they said.

"When it comes to tackling aging, experts are advising the government that muscle aging is caused by factors such as inactivity," said Jamie Timmons, a professor in the university's sport, exercise and health systems department. "However, we looked at people in the UK and the USA and... we did not observe physical activity altering the age-related biological changes."

Timmons said that while exercise might provide some good functional benefits for some, it would not stop the loss of muscle in others. The researchers found no simple link between exercise and retarding of the muscle aging process.

In fact, repetitive exercise might yield counter-productive effects in some people. Ten-percent of regular exercisers might experience hypertension and nearly as many would incur a greater risk of developing diabetes, as a result of their workout regimens.

While Timmons cautioned against a "one-sized approach" for everyone, he said some might benefit by focusing more on diet and sleep.

Depending upon how you see it, the new research might either compliment or contradict a 2011 study published in the journal Physician and Sportsmedicine demonstrating a link between regular exercise and retention of lean muscle mass in older adults. As reported by the National Institutes of Health, researchers in that study found a link between regular exercise and the retention of muscle mass -- but in a particular subset of the population dubbed "master athletes."

There, researchers followed 20 men and 20 women in their 40s, 50s, 60s and 70s, who trained 4 to 5 times per week. The researchers concluded that "participating in chronic high-level exercise may not demonstrate the same loss of total lean muscle mass and lower-extremity performance witnessed with sedentary aging. [Such] athletes continue to exhibit high levels of functional capacity and quality of life throughout their lifespan...."