Edited by Kate Findley and proofread by Angela Shoemaker, The Great Courses Daily
The creative power of our mind is remarkable and can even impact us physically. Professor Vishton explains.
Our imagination can have a powerful effect on our physical strength. To understand how, go to a safe place, have a seat, close your eyes, and imagine that you’re standing with your legs about shoulder width apart.
In your right hand, imagine holding a heavy barbell. The texture of the metal is rough, and the barbell feels cooler than your skin where it touches your hand.
Now, bend your right arm and lift that heavy barbell all the way to your shoulder. Feel the strain of that lift. When you’ve bent your arm as far as it will go, lower the barbell slowly until it’s back at your side.
If you’ve been following along, open your eyes and relax. You’ve physically done nothing with that arm, but your brain did a lot of work imagining your body doing something.
You just did one repeat of that barbell curl exercise, but in some studies, people have been asked to imagine doing many. When you do so, your brain gets tired.
Unbelievable as it sounds, your muscles get a workout as well. One of the best studies demonstrating this concept focused not on the arm muscles but on the hip flexors.
The hip flexors are muscles at the top of your legs and around your hips that contract to bend each leg up, pivoting around the pelvis. When you kick your leg forward, or even just swing your leg forward as you take a step, this is the muscle group that makes it happen.
Building Strength with Imagination
In a study at Bishop’s University in Quebec, Erin Shackell and Lionel Standing recruited participants and tested the strength of their hip flexor muscles using an electronic device called a sphygmomanometer. The sphygmomanometer recorded the maximum pounds of force that each participant could produce on the first day of the study.
Once the participants’ baseline strength had been assessed, they were randomly assigned to one of three conditions. The control participants left and returned two weeks later.
Participants in the physical training condition undertook a strength-training program for their hip flexors. Five days per week, for two weeks, these participants visited a gym and completed four sets of eight repetitions of lifting a weight with a hip flexor exercise machine.
A hip flexor machine has a padded bar that you place against the front of your leg. This bar is attached via a cable and a pulley wheel to a stack of weights.
As you try to lift that leg upward, you have to lift not just the weight of your leg but also the stack of weights. In the experiment, the weight was gradually increased over the course of the sessions.
Participants in the mental training condition were shown the hip flexor machine during the first visit—as all of the participants were—but they did not use it for the next two weeks. Instead, they imagined using it.
Specifically, they imagined performing four sets of eight reps five times per week, the same exercise that the physical training participants actually performed. Over the course of the two weeks, they were instructed to imagine using heavier and heavier weights.
At the end of the study, everyone returned to the gym for a repeat of the strength assessment that they’d completed at the start of the experiment. The physical group increased their performance on the strength test by an average of 36 pounds.
The control group didn’t change significantly. The mental training group, however, without ever touching the weight machine, improved their hip flexor strength by 32 pounds—just a few pounds less than the physical training group.
The Power of the Mind
According to Professor Vishton, when you imagine performing a strength exercise, the muscles that you imagined using will increase in strength. This study was conducted only with the hip flexor muscles, but the study has been replicated many times with different muscle groups: the lower leg, the upper arms, and the muscles that control the wrists and fingers.
When someone has to wear a cast for several weeks due to an arm injury, they typically lose a lot of arm strength during that period. Imagining flexing and moving the arm—even when it’s impossible to actually do so—results in stronger arms than those of control group participants.
According to Professor Vishton, though, you still need to engage in physical exercise, rather than using imagination as a substitute for strength-training or aerobic exercise. When you fatigue and damage muscle fibers during physical training, the body responds by repairing them and making them a little bigger than they were before.
Thus, physical training makes muscles bigger. Mental training, by contrast, doesn’t change the size of the muscle fibers very much. Some research suggests not at all.
Imagery seems to increase the strength of the signals sent to the muscles. After imagery practice, when you make an actual movement, your motor cortex will become more active than it otherwise would have.
A greater number of action potentials are conveyed to the muscles, causing a greater number of muscle fibers to respond when your brain cells call upon them to do so. The result is that more force is generated by the muscles.
There are many benefits to actually exercising, as opposed to merely imagining it. Your heart, lungs, and circulatory system will all benefit from physical training in ways that mental training won’t help, and real physical training burns a lot more calories. Still, it’s remarkable that your imagination could have this type of effect on muscle strength.
This article was edited by Kate Findley, Writer for The Great Courses Daily, and proofread by Angela Shoemaker, Proofreader and Copy Editor for The Great Courses Daily.
Peter M. Vishton is Associate Professor of Psychology at William & Mary. He earned his PhD in Psychology and Cognitive Science from Cornell University. Before joining the faculty of William & Mary, he taught at Northwestern University and served as the program director for developmental and learning sciences at the National Science Foundation.