A recent study published in the Journal of Neurophysiology suggests that simply imagining your muscles at work can have a profound effect on their physical strength, especially when those muscles have been rendered inactive by an injury.
Scientists at the Ohio Musculoskeletal and Neurological Institute (OMNI) at Ohio University asked 29 healthy adults to wear hand-wrist casts that immobilized their non-dominant arm for four weeks.
During that period, some participants were asked to imagine using the immobilized muscles in their hands and wrists, but not actually flex or activate those muscles physically. They performed these imaginary training sessions, which were 11 minutes long, five days a week. To ensure their wrist muscles were not activating, participants were hooked to a machine that monitored their muscle activity.
The remaining individuals in the control group did no imaginary exercises.
At the end of the four-week trial, those who performed the mental imagery showed a whopping 50 percent reduction in lost strength compared to the control group.
"The results illustrate how profound of a role the nervous system plays in muscle strength and weakness," said lead researcher Brian Clark, Professor of Physiology and Neuroscience at OU and Executive Director of OMNI. "For the past 30 years, most people have linked strength (or weakness) to muscle mass, but this work clearly shows that at least 50 percent of disuse-induced muscle weakness is driven by the nervous system."
The brain and nervous system have been considered key players in muscle strength for several years now. A study published in the same journal in 1992 found muscle strength gains in the fingers over time from mental imaging alone, no muscle activation necessary. Many others have found that imaginary exercise activates the same areas of the brain that are activated when actually exercising. A 2004 study found that "mental contractions" can help drive strength gains.
What sets the OMNI study apart is that it's the first to demonstrate that imagery training can curtail a loss of strength during a duration of "disuse," or immobility.
According to Clark, when you perform an exercise like the Bench Press, your brain sends signals along your body's neuromuscular pathways telling the muscles in your chest and triceps to fire. This study seems to indicate that merely thinking of firing those muscles helps maintain the connection along those pathways.
The recent study also suggests that because of the mind-muscle connection, exercise visualization may have several uses in injury rehabilitation. "Conceptually speaking, [this treatment could help] injuries that result in the inability to move a limb, such as post-surgery or fracture," Clark said.
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