Studied ballet for 30 years- In every class, movements are done first on one side, then the other. Tendues with right leg then with left. Dancers who study daily switch starting sides on Tuesday, Thursday, Saturday. This has several effects- all sides are practiced equally. But more important- one side is always better than the other (eg, turns to the left vs turns to the right), Gains on the stronger side can migrate to gains on the weaker side. Glad to learn that “mirroring” is real. Muscle memory, and running through a routine in your head may well be related!
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When I was 17, I fell and landed upon a metal stake in the ground that opened a gash in my wrist. A tendon was severed that required surgery to repair and a cast was placed on the arm for healing. Upon removal of the cast, I was shocked by the atrophy of my forearm muscles.
The doctor gave a stern warning not to over tax the arm when the cast was removed, but I was a dedicated weight lifter. As soon as I could close my hand around a dumb bell, I resumed lifting weights. The doctor marveled over the speed of my recovery.
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I can't wait to find out how this works. The interesting question will be whether we can use this to strenghten muscles all over the body wihout needing to exercise at all. For those in wheel-chairs or bed-bound, this might well be a life saver.
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This isn't news at all. The first scientific evidence of this phenomenon dates back to 1894 when Scripture et al first reported on it. It's also termed "cross-education" or "bilateral transfer," NOT "mirroring." If they would have done a more thorough literature review, they would also know that the mechanisms are likely ALL neurological, predominantly of cortical origin. How is Canada a century behind on this? Yikes. I've done three studies of my own on this topic and along with other investigators have moved on to trying to augment these affects via the mirror neuron system.
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Good comment, you are correct in that Scripture reported this in the late 1800's. If you read the actual manuscript that this article is written on you will see we as the authors don't claim to be the first to report it. We also call it cross-education. You are also accurate in your statement regarding the vast majority of the evidence being cortical in nature, with the two dominant theories being the bilateral access hypothesis and the cross-activation hypothesis (see Ruddy and Carson, 2013). What this study points out (along with the 4 studies using immobilization previously) is that muscle size changes aren't observed in traditional cross-education work and it is possible that by introducing immobilization we are either able to observe a potential muscle mechanisms (causing the preservation) that we cannot observe in traditional studies, or there is something unique to the immobilization that introduces another potential mechanism at play.
This is the 5th study to observe strength preservation with immobilization, and the 4th to observe size preservation. What is novel about this work is the investigation into size and strength sparing specificity. This is the first study to show that cross-education is specific to the muscle trained for sparing effects (specificity has been seen in non-immobilization studies where increases in strength or skill are seen), and also that eccentric training resulted in strength preservation across multiple contraction types.
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If this is true, I am a bit confused. In 1999, I am injured the tendon under my right foot's arch. I had to be on crutches for three months and not put any weight on that foot. After three months, the PT asked me to begin to put a little weight on my right foot. It was extremely difficult. Clearly I was "exercising" my left foot for the full three months whenever I walked. It didn't seem like that had any effect on my right foot.
Why not?
On the other hand....
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I am left handed. I think most lefties are somewhat ambidextrous because we have to adapt to a right handed world.
The phenomenon that I notice is that if a limb is injured, the contralateral hurts also. The Good limb gets jealous of the bad.
As an acupuncturist I can tell you that this is not news to us. We are taught early on in our education that the left side of the body can treat the right side, that upper body can treat lower body(and vice versa) and that the inside of the body can be treated by using the outside. This last idea is a simplification of what we do if we’re treating someone for digestive or other internal conditions. It’s not unusual for me to choose points in the elbow for the knee, hip for shoulder, ankle for wrist or the opposite, in any case. Points may be chosen on the same side or the opposite side. My assessment and choice is made through palpation.
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Can confirm this anecdotally. Twelve years ago I moved to a location on the right side of a river I fish a lot, forcing me to make 80-90% of my casts with my non-dominate left hand. Though staying with it over all these years, my left hand casting has only marginally improved. My right hand casting, however, which I almost now never do, has improved leaps and bounds in regard to precision, control, and power. Noticeably. I can feel my right hand learning from my left, and more than my left.
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1- it is to everyone's benefit to at least try to be competent on both sides. for instance, i was told and taught to golf righty, even though i am lefty. when no one said 'you must hold the tennis raquet in your right hand', i proceeded to play lefty. never needed a backhand stroke, either. and, if i were say, painting a room, i would just switch hands when i reached the corners.
2- i have been paralyzed nearly completely on my right side now for 31 years, and obviously there are things i can no longer rationally even try to do, but i DO try everything i CAN still do from a two-handed -balanced- perspective. it is annoying at the least when synergy kicks in and the right side gives an autonomous response/opposite/backward response to what the left is doing - but at least there is not much difference in mass on the two sides.
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We already know that mentally practicing complex tasks such as playing a piano can help one play better, or remember how to play if one has no access to a piano. It makes sense to me that exercising one limb helps the other.
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Like commenter Tom-DNA, I had heard about such effective mirroring many, many years ago... At least back in the late 1980s.. but I do think it's excellent that this is being picked up again and reported!
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Fascinating, practical and harmless to implement.
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Nothing new for Feldenkrais practioners. Mr Feldenkrais was a genius but from the medical world pretty much ignored.
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Feldenkrais practitioners have used this aspect of brain function for many year with one addition - the patient is taught not only to do the movements in the unaffected side, but to IMAGINE the movements and the sensations in the side that is affected. The only purpose of using the healthy side first, is to learn WHAT to imagine on the affected side.
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“you may want to talk with your physician or physical therapist about exercising your uninjured limb”...
Guaranteed that it is not covered by insurance though. More information to be dangled tantalizingly in front of those who need it but cannot have it, because they are not wealthy enough.
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There is no extra cost to lifting cans of food, milk containers filled with water and so forth. Almost everyone can exercise if they choose to do so, especially since information on how to do so is widely available online and in libraries.
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Human kinetics/kinesiology labs specialise in very small "n" studies with little attention to requisite sample sizes to avoid bias and achieve adequate statistical power then report relative (not absolute) differences in the range of 10 - 30% which any competent methodologist will tell you is not significant -- i.e. is probably meaningless. To make not too fine a point of it: junk science.
Anecdotally, parallelism in muscle development has been noted from the ancient Greeks forward. It's long been hypothesised that this has nothing much to do with the biomechanics of exercise but quite a lot to do with how the brain and nervous system operate. We all too often make the usual mistake of thinking mind and body/brain and flesh and thinking/emotions/bodily processes are separate as opposed to complex interactive systems.
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Appreciate the story. I was talked into having rotator cuff repair on my left shoulder, and now the right one is having issues too--can't get my right hand much higher than the small of my back when I used to be able to clasp hands (cow face pose) before the surgery.
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I'm not sure why a study of 16 subjects -- which can at best be described as exploratory -- merits attention in the Times. It encourages people to draw conclusions based on very preliminary data that has not been confirmed by robust trials. This section runs a lot of similar articles - big headlines based on minimal data. The vast majority of these exploratory studies are not borne out by larger investigations ... in fact, many are never further pursued. This just adds to the sea of "noise" that confuses consumers and leads to distrust of more sound medical information.
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Another example of life’s tendency towards symmetry.
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This is so interesting to me! When I had my right knee replaced, I got the sense that my "good" knee was teaching my new knee how to work in my body. I felt this very strongly. I would often tell people considering bilateral knee replacement that if I were they, I would get it done one knee at a time, even if it cost more that way. So according to this article, my gut feelings were not wrong!
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Interesting. However, the article failed to note that the “exercise” group ended up with much greater muscle imbalance. The exercisers gained 30% strength in the right and lost 2% on the left (difference of 32). The nonexcersise group lost 7% on the right (suggesting immobilization also has a mirroring effect?) and 21% on the left (difference of only 14). Strength imbalance can lead to all sorts of unconscious compensations that can cause injury, so those in the PT realm-professional or amateur-should use caution in implementing the suggestion of this article, which seems to double such imbalance.
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Thanks for this. I am 4 months post broken foot and have limited exercise to what I can do bilaterally and that balances opposing muscles for this reason. When I saw this article I was wondering if I had missed a chance to maintain more leg strength but you have saved me the regret.
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Middle-Aged Professor, Your point of greater imbalance is important to address, but does not negate the thrilling improvement of strength while injured.
Apparently you are still young enough that you regain strength easily! I would far prefer to gain a great deal of strength, even if it was unbalanced, than to lose a lot of strength, which is likely to be a more permanent loss as one gets older. 30% gain of strength would be a miracle to me, while your preferred method of losing 21% strength would be torture.
Proper physical therapy can help deal with muscle and other imbalances. I prefer Functional Manual Therapy™, which retrains the body to proper balance and function.
My recent problem was major unconcious compensations for some aging pains. I have been retrained to maintain proper posture and movement despite little gains in strength.
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I did not mean to recommend one approach over another. I love strength! I only mean to point out (as I think the article should have) that the study subjects had an iimbalance exacerbation with this approach, and that should also be considered/attended to by potential adopters.
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Interesting. Does it make a difference if a person is ambidextrous to some extent? I ask this because my mother told me that when I was a young child I never displayed any preferences in terms of handedness. When I used to work in the lab I had to work very hard to keep one hand "quiet" while teaching myself to inject lab mice. I then taught myself to do it with the other hand as well. I taught myself to breathe on my left side as well as my right when it comes to swimming and doing freestyle.
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Indeed, this phenomenon was explored and implemented years ago by Moshe Feldenkrais (Awareness through Movement). For many years, Feldenkrais practitioners have been helping people overcome muscular imbalances, postural issues, sports injuries, and many other conditions, as well as enhancing overall physical and mental equanimity.
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I learned about this phenomenon in a Feldenkrais class, although I can't help but wonder why we are not all ambidextrous.
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When I was 5 years old I broke my left elbow. I was in a cast for almost 2 months. I was born right hand dominant. Having to do simple tasks like buttoning my shirt one handed made realize that had I broken my right arm instead I would have been basically helpless. From the moment I got my cast off my left arm I made a concerted effort to try to do everything with my left had as well as I could do it with my right. By the time I was a teen I was fully ambidextrous. I can throw a baseball and bat with just as well with both hands. I can write fast and legibility with both, though the handwriting is a little different. I can throw a football, dribble and shoot a basketball, and bowl just as well with both. Darts, shoot pool, you name it and if I can do it at all I can probably do it just as well with both hands.
So to answer your question, why are we all not ambidextrous? I think it is because most people never try to be. It took me years of practice.
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Me too! I was in high school when I realized it was silly to have a useless side. My Dad is ambidextrous so that provided some motivation as well. It takes effort, but so worth it to be able to switch hands/feet. :)
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