If you're looking to boost your strength, try flexing some mental muscles.
According to a new study from the Ohio Musculoskeletal and Neurological Institute, practicing mental visualization can actually build physical strength. Researchers found that mental imagery helped a group of immobilized study participants maintain strength and reduce associated muscle loss.
In the experiment, 29 healthy participants spent four weeks in rigid casts that extended from their elbows to their fingers. These types of casts, typically used to help a broken bone heal, are associated with muscle loss, so the researchers expected the participants to lose some strength. A control group of 15 did not wear a cast.
Within the immobilized group, 14 participants were asked to regularly perform a mental imagery task, in which they were verbally guided to imagine intensely contracting their wrist for five seconds and then resting for five seconds. The participants performed the task in sessions, five times per week. The other 15 participants in the immobilization group did not perform the exercise.
After four weeks, both of the groups whose arms had been in a cast had lost muscle strength in the immobilized limb, compared to the control group. However, the group that performed the mental imagery tasks lost significantly less muscle (24 percent loss) than the group who did no imagery (45 percent loss). The imagery group also experienced quicker rebounding of "voluntary activation," the nervous system's ability to activate the muscle.
The results suggest that strength is controlled by not only the skeletal muscle, but also the nervous system, which plays a role that is not yet fully understood.
"These findings suggest neurological mechanisms, most likely at the cortical level, contribute significantly to disuse-induced weakness, and that regular activation of the cortical regions via imagery attenuates weakness and VA by maintaining normal levels of inhibition," the research team wrote. In other words? When muscles aren't used, it may be due to neurological inactivity in addition to physical inactivity.
Previous neurological research has found, in other contexts, that mental practice is on par with physical practice. A study of the brains of weight lifters found that the brain patters activated when the weight lifters lifted 100 pounds was similar to when they merely imagined lifting 100 pounds. Research from the Cleveland Clinic also found that performing a "virtual workout" in your head is enough to noticeably increase muscle strength.
"That suggests you can increase muscle strength solely by sending a larger signal to motor neurons from the brain," Guang Yue, an exercise physiologist at the Cleveland Clinic Foundation in Ohio, told New Scientist.