IT SOUNDS like a couch potato鈥檚 dream. Just imagining yourself exercising can
increase the strength of even your large muscles. The discovery could help
patients too weak to exercise to start recuperating from stroke or other injury.
And if the technique works in older people, they might use it to help maintain
their strength.
Muscles move in response to impulses from nearby motor neurons. The firing of
those neurons in turn depends on the strength of electrical impulses sent by the
brain. 鈥淭hat suggests you can increase muscle strength solely by sending a
larger signal to motor neurons from the brain,鈥� says Guang Yue, an exercise
physiologist at the Cleveland Clinic Foundation in Ohio.
Yue and his colleagues have already found that visualising exercise was
enough to increase strength in a muscle in the little finger, which it uses to
move sideways. Now his team have turned their attention to a larger, more
frequently used muscle, the bicep.
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They asked 10 volunteers aged 20 to 35 to imagine flexing one of their biceps
as hard as possible in training sessions five times a week. The researchers
recorded the electrical brain activity during the sessions. To ensure the
volunteers weren鈥檛 unintentionally tensing, they also monitored electrical
impulses at the motor neurons of their arm muscles.
Every two weeks, they measured the strength of the volunteers鈥� muscles. The
volunteers who thought about exercise showed a 13.5 per cent increase in
strength after a few weeks, and maintained that gain for three months after the
training stopped. Controls who missed out on the mental workout showed no
improvement in strength.
The researchers are now repeating the experiment with people aged 65 to 80 to
see if mental gymnastics also works for them.
