Regular training in front of a mirror will eventually lead to impaired physical performance, with specific decreases in reaction time, rate of force development, and balance.
Ditch the mirror.
Show Me the Study!
Sorry, but if you require scientific evidence with empirical data, I don't have it.
In the performance world, it's not always necessary to wait for someone in a lab coat to "prove" what your body and experiences have already been telling you. While there may be no scientific evidence confirming my hypothesis, that doesn't mean I've abandoned all reason. My argument is based on logic and backed by years of in-the-trenches experience.
So, let's discuss.
Mirror, Mirror, On the Wall
The typical commercial fitness center has every inch of available wall space covered by mirrors. This might be a problem.
Olympic lifting centers, unlike regular gyms, contain very few mirrors. Lifters there will intentionally turn away from the mirror while doing their lifts. Interesting...
Now, I'm a competitive powerlifter that usually trains in heavily-mirrored commercial fitness centers. I noticed that in a competition, it would feel weird to squat without a mirror in front of me. So I started blocking the mirror while squatting. I wanted to "feel" the correct depth and not get used to using the mirror to judge.
Then while doing box jumps in front of a mirror one day, I realized that I was seeing myself jump and land instead of feeling the movement. It just didn't seem right to me. I decided to dig deeper.
Eyes vs. Inner Ears
Old people fall a lot more often than younger people. There are several reasons for this, but a leading hypothesis is that as we age, our internal sense of balance – which comes from the inner ear – desensitizes, and we start to rely on vision to maintain balance.
We use our eyes to see how we're aligned. If you start to fall over, things won't appear straight and you'll attempt to correct the problem. This system works, but not as well as relying on the inner ear to provide balance.
Using vision creates a slight delay in the reaction time necessary in correcting a balance problem. Light must travel from the objects around you to your eyes for you to interpret before sending out the signal to correct the loss of balance.
When you rely on your internal sense of balance, it's more sensitive to small changes and can immediately send out a signal to correct the imbalance when it detects it. The visual system is only slightly slower, but that little bit of time can make a difference and keep you on your feet.
A Simple Test
A test to see if you rely primarily on vision for balance is to stand on one foot and maintain balance for about 15 seconds. When you're relaxed and comfortable in that position, close your eyes and see how long you can go.
If you fall over within a second or two of closing your eyes, you're likely relying on vision for balance.
This is very common in older people. Younger people can often maintain their balance with their eyes closed – although I suspect trainees who've been lifting in front of a mirror for the last 10 years might fall over quickly when they close their eyes, even at a young age.
Performance and Balance
Relying on the mirror for feedback can have negative consequences. It could mean a slower reaction time and a slower rate of force development.
Remember that the visual system is slower than the internal system. If you use the mirror, you double the reaction time because you must see yourself move in the mirror, have that image come back to you, and then correct it.
On a slower lift that might not be a big deal, but on a big or explosive lift where strength and power are important, it can be significant.
How to Fix It
First, avoid using mirrors for the majority of lifts. Arranging a few yoga mats to cover up the mirror usually works well without bothering gym management.
In college we used a big bed sheet to cover up the mirror in front of the squat rack. (I worked in the gym, so that helped.)
Another option is to simply look away from the mirror while lifting, either slightly up or down, or even close your eyes while you lift.
You can also turn around and face away from the mirror, although this can be problematic while squatting. In a typical commercial gym you'll wind up staring at another mirror further away or a roomful of members going about their workouts. The added risk of having to walk backwards to re-rack the weight also make this impractical.
The issue isn't just limited to squatting. Deadlifts, military presses, rows, even heavy biceps curls are best performed away from the mirror, not to mention all variations of the Olympic lifts.
Pros and Cons
I prefer looking at all aspects of something rather than saying it's completely good or bad. Mirrors in the gym aren't all bad when used occasionally.
The mirror can provide instant visual feedback on proper form, and it can help teach body awareness. It also allows trainees to see themselves from different angles, which can provide valuable feedback.
It's also good for your confidence to see yourself doing something impressive like lifting a heavy weight. It can be cool to see yourself pumped up with veins-a-pulsing in the middle of a hardcore workout, too.
Part of my fitness philosophy has roots in bodybuilding, so I appreciate the visual feedback a mirror can provide. If someone hopes to be a competitive bodybuilder, he or she will have to spend a good amount of time learning how to pose, which is best done in front of a mirror.
That said, being a mirror-user in the past, I now believe the negatives outweigh the positives for big lifts.
With the low cost of a decent digital camera, many benefits of the mirror can be derived through filming your lifts. Watch the video immediately after the set. This provides better technique cues and feedback than a mirror, minus the visual distraction.
Additionally, a video of yourself doing something impressive is just as cool as seeing it in the mirror.
The Mirror Effect
The prolonged, repeated use of a mirror during training can result in a negative effect on performance. If you're skeptical, try covering up or avoiding the mirror on the majority of your lifts and see how you respond.
It might be awkward at first, and it will likely take some time to rewrite ingrained motor patterns, but I encourage you to persevere.
Removing the mirror from your workouts could lead to increased reaction time, increased rate of force development, and better balance. And if those things aren't enough to boost your ego, just bring along a camera.
Agree with me or think I'm crazy? Hop on the LiveSpill and let me know!