We yearn to believe that we can get fit without effort. We build “ab belts” to electrocute our muscles to give us six-packs. We invent chocolate-chip cookie diets to make us thin while eating fat. We wish to get fit from doing absolutely nothing. We wish to lie in bed, think about going to the gym and then, poof, obtain the body of a Greek god.

Well, a remarkable new study from Brian Clark at Ohio University shows that sitting still, while just thinking about exercise, might make us stronger. Clark and colleagues recruited 29 volunteers and wrapped their wrists in surgical casts for an entire month. During this month, half of the volunteers thought about exercising their immobilized wrists. For 11 minutes a day, 5 days a week, they sat completely still and focused their entire mental effort on pretending to flex their muscles. When the casts were removed, the volunteers that did mental exercises had wrist muscles that were two times stronger than those that had done nothing at all.

The idea behind the research is not a new concept – just a concept that’s often neglected in the field of neuroscience: our bodies and our brains evolved together. Even though we treat our mind and bodies as two separate entities (brain vs. brawn; mind vs. matter), they are ultimately and intimately connected.

Indeed, even before Brian Clark published his study, other researchers had demonstrated links between the brain and the muscles. Ten years ago, Guang Yue at the Cleveland Clinic reported that imaginary exercise increases the strength of finger muscles by up to 35%. Just five years ago, Kai Miller at the University of Washington, showed that imaginary exercise activates the same brain areas that are activated during real exercise. Brian Clark’s research adds to this body of knowledge and provides compelling evidence about the role of neuromuscular pathways in strength training.

To examine brain-muscle pathways, Clark and colleagues placed a magnetic field above the motor cortex and stimulated neurons in the brain. When they turned on the magnetic field, they saw the muscles of the volunteers flex and then become momentarily paralyzed. By measuring the amount of muscle contraction and the duration of paralysis, Clark and colleagues were able to make inferences about the connections in the brain. The longer the paralysis lasted, the weaker the neuromuscular connection. Not surprisingly, the volunteers that performed imaginary exercise had stronger neuromuscular pathways and hence, stronger muscles. The mentally-lazy volunteers had weaker neuromuscular pathways that were beginning to degrade.

Whether we get weak from wearing a cast, or we get weak from lack of exercise, or we get weak from aging, keeping the mind active keeps the body healthy. But, the mind alone cannot keep the muscles strong … any more than zapping your muscles with an ab belt builds a six-pack. Lifting weights or playing sports is more effective than mental exercise alone or muscle-zapping alone, because it activates both the mind and the body at the same time. In fitness, and in health, the mind and the body both matter.