by Richard K Mchugh

Why write about this?

In recent classes multiple instructors have mentioned closing your eyes. I am a true novice at Aikido but have a wealth of knowledge and years in medicine. I decided to use my medical knowledge to analyze why closing my eyes may help my training. I also read chapter 9 of Sensei’s book entitled “Writing about Aikido is part of Aikido training”, which made me think that it might be of value to write out these thoughts. With the support of Rob and Donnie, I dove into this topic.

How do you balance?

There are three systems of balance: vision, the vestibular system and proprioception.

Vision is obvious but interesting. We live in a very visual world with our cell phones, tablets and other stimuli. I think this leads to overreliance on the visual system for our balance. When balancing on one leg it is effective to focus on a single spot to improve your balance. Similarly, dancers use a technique called “spotting” when spinning, in which they repeatedly look at a single spot by whipping their head around to allow their eyes to focus on that spot for as long as possible during each revolution. In darkness our balance suffers because we lose those visual cues about our position in space.

Secondly, we have the vestibular system. This involves structures in the inner ear including the three semicircular canals (detecting rotatory movement) and the urtricle and saccule (detecting linear movement). The inertia of the crystals to movement stimulates nerves when those crystals bend (lagging) at their attachments proportional to the movement. Through the vestibulocochlear nerve this sends signals to your brain, which collates that information into a motion sensation. This is truly amazing when you think about how you go through many different movements and this system detects the acceleration/deceleration and changes in direction. However, the vestibular system tracks movement of your head alone. If your head is still but your arm is moving then the vestibular system is not directly involved. Disease processes such as benign position vertigo or Meniere’s disease in which you feel vertigo out of proportion to your movement, or perhaps without movement, can be devastating and greatly affect ability to move smoothly and safely.

Finally, there’s the proprioceptive system. To my understanding there are muscle fibers, ligaments and tendons that constantly signal body position to the brain. The brain sends feedback to allow holding that position or to continue smooth movement, which is a truly fast process. When proprioception is used in movement it is called kinesthesia. The proprioception system is involved in both gross (eg. Walking) and fine (eg. Writing) motor skills. This allows the non-visual development of muscle memory such as used in typing, piano playing, a great golf swing and presumably in swinging a bokken. In my area of expertise this allows the brain to receive proprioceptive feedback and then to fine tune the muscle contraction in vocal fold tension and bulk in singing in order to produce smooth tone and transitions.

Closing your eyes and touching your nose is completely based on your proprioceptive system. Similarly, the proprioceptive system can sense weight and resistance, which must be very important in keeping your center through an aikido movement. Closing your eyes and moving your body (including your head) involves proprioception and vestibular sensation.

I’ve frequently discussed the proprioceptive system in a more basic way with my residents noting that standing at the edge of a precipice feels like you might fall over. Presumably that is due to the visual cues being so distant that they provide less stability. But if you could simply put your finger against a stable structure (eg. A guard rail), then your proprioceptive system through your shoulder girdle would add to the proprioceptive signals through your feet/legs/hips and help you feel much more stable.

Your proprioceptive system can have reduced sensitivity through peripheral neuropathy, among other insults. Diabetes with prolonged uncontrolled blood glucose can cause peripheral neuropathy. Similarly, but more slowly, aging leads to a decline in nervous signaling including proprioception. From the CDC in 2024, more than one in four adults older than 65 experience a fall per year and falling once more than doubles your risk of falling again. I have personally seen the devastating effects of a “ground level fall” in terms of facial fractures and brain damage. I feel that improving our non-visual proprioceptive and vestibular senses and our ability to perform a safe fall or roll could be incredibly important as we age.

How is closing your eyes involved in Aikido training?

In my enormous (not!) 4 months of Aikido training, there have been a handful of times that Senpai have recommended closing eyes. Most recently this has been from Rob in Kihon Kunren practice and from Grace in ukemi training with a push to the ukemi with eyes-closed leading into a fall. So, why would closing your eyes in these instances and others provide benefit?

The science involving lack of sight with balance is varied and not fully developed.

First, I looked at balance training with eyes open and found the study entitled “Exercise-induced neuroplasticity: Balance training increases cortical thickness in visual and vestibular cortical regions”. This shows that balance training changes brain structure. Note that vision processing regions of the brain were changed.

Next, I searched for studies comparing balance in eyes open versus closed condition. There is sparse scientific data, although a similar google search shows that many physical therapists utilize eyes closed as an advanced move in static and perhaps movement balance training. Presumably closing our eyes during static balance training will lead to greater awareness of our proprioceptive sensations. If this involves movement then perhaps our vestibular system will be included.

The most applicable study I found regarding balance in “athletes” was by Hutt and Redding 2014 entitled “The effect of an eyes-closed dance-specific training program on dynamic balance in elite pre-professional ballet dancers: a randomized controlled pilot study”. This study showed that in a 4 week period pre-professional ballet dancers were able to improve static and “reach” balance on most testing only if they closed their eyes during the training. Does this mean that an aikidoka who already has excellent balance can improve it by adding some training with closed eyes? I think so and plan to try this during my personal practice.

The next question I asked is how would this work? Is it simply more sensitivity or do our brains actually change similar to the first study with eyes open balance training. I found the study by Rogge et al 2019 entitled “Improved balance performance accompanied by structural plasticity in blind adults after training”. This study shows that in late blindness (i.e. people born with sight that is later lost) there are notable improvements in balance after training in comparison to no training, and those improvements appear to be related to changes in the brain as measured by MRI. Unfortunately, there is not a control group with sight. The preceding study about ballerinas showed that there were similar improvements in sighted individuals with eyes open undergoing a balance training program such that it is unclear the effect to which eyes closed (or blindness) improves the balance function.

How can closing my eyes improve my Aikido training?

In Kihon Kunren it seems that the practice of feeling my center will allow my brain to instinctively feel it as I move through Aikido techniques. At its most obvious this should improve my balance. In ukemi, by closing my eyes I am responding to a non-visual stimulus, which should lead to a more authentic reaction and sensitivity to that stimulus. Listening to my Senpai, I expect it will also lead to fluidity and conservation of motion in my aiki. I look forward to applying closed eyes to more and more techniques to understand where it may be most helpful.

Can this improve my life?

As I noted above, the risk of experiencing a fall is about one in four for people older than 65 years. I’m approaching that mark much too quickly. I found the following study comparing age to balance, and including eyes open and closed entitled “Whole-brain grey matter density predicts balance stability irrespective of age and protects older adults from falling”.

If the prior study by Rogge et al 2019 and analogous studies in sighted individuals are correct that balance training leads to neuroplasticity with some areas of grey matter increased density, then the above study by Boisgontier et al 2016 shows that by performing balance training we can protect ourselves from falls as we age. Again, eyes open versus closed is not directly tested. But going back to the first study by Hutt and Redding 2014 in ballerinas certainly suggests that there is significant potential for improved balance.

To me this suggests that even at my advanced age I can train with eyes closed and through neuroplasticity it will improve my aikido abilities. By closing my eyes in parts of my home practice and during Kihon Kunren I hope to experience Aikido more deeply.

Selected abstracts:

J Neuroimage. 2018 Oct 1:179:471-479.

Exercise-induced neuroplasticity: Balance training increases cortical thickness in visual and vestibular cortical regions

Ann-Kathrin Rogge ¹, Brigitte Röder ², Astrid Zech ³, Kirsten Hötting ⁴

Abstract

Physical exercise has been shown to induce structural plasticity in the human brain and to enhance cognitive functions. While previous studies focused on aerobic exercise, suggesting a link between increased cardiorespiratory fitness and exercise-induced neuroplasticity, recent findings have suggested that whole-body exercise with minor metabolic demands elicits beneficial effects on brain structure as well. In the present study, we tested if balance training, challenging the sensory-motor system and vestibular self-motion perception, induces structural plasticity. Thirty-seven healthy adults aged 19-65 years were randomly assigned to either a balance training or a relaxation training group. All participants exercised twice a week for 12 weeks. Assessments before and after the training included a balance test and the acquisition of high-resolution T1-weighted images to analyze morphological brain changes. Only the balance group significantly improved balance performance after training. Cortical thickness was increased in the superior temporal cortex, in visual association cortices, in the posterior cingulate cortex, in the superior frontal sulcus, and in the precentral gyri in the balance group, compared to the relaxation group. Moreover, there was evidence that the balance training resulted in decreased putamen volume. Improved balance performance correlated with the increase of precentral cortical thickness and the decrease in putamen volume. The results suggest that balance training elicits neuroplasticity in brain regions associated with visual and vestibular self-motion perception. As these regions are known for their role in spatial orienting and memory, stimulating visual-vestibular pathways during self-motion might mediate beneficial effects of physical exercise on cognition.

J Dance Med Sci 2014 Mar;18(1):3-11.

The effect of an eyes-closed dance-specific training program on dynamic balance in elite pre-professional ballet dancers: a randomized controlled pilot study

Kimberley Hutt ¹, Emma Redding ²

 

Abstract

Visual conditions for a dancer vary greatly between theatrical performance environments and dance studios, and this variability may be detrimental to their dynamic balance performance, particularly under stage lighting. In order to maintain balance control, dancers reportedly rely heavily on visual input, yet those who rely more on proprioceptive strategies for balancing have been found to be more stable. The purpose of this study was to assess the capability of an eyes-closed, dance-specific training program to nurture in dancers proprioceptive mechanisms that may facilitate their dynamic balance control. Eighteen elite pre-professional ballet dancers were randomly assigned to either a control (eyes open) or experimental (eyes closed) group for the intervention. The balance abilities of all subjects were tested using five dance-specific variations of the Star Excursion Balance Test before and after a 4 week balance intervention. Reach distance and time to complete the tests were recorded separately as indirect measurements of dynamic balance. The intervention consisted of dance-specific, eyes-closed exercises integrated into the dancers’ daily ballet class and designed progressively to challenge the dancers’ balance. During the intervention period, the control group undertook the same exercise program with their eyes open. Results revealed significant improvements in time to complete the three “timed” balance tests, and distances reached significantly improved in one of the two “reach” balance tests. No significant improvements were observed in the control group for any variation of the tests. These results indicate that dancers can be trained to adopt proprioceptive strategies to maintain dynamic balance, which consequently improves their balance performance. Such findings could encourage use of eyes-closed training in daily dance classes due to its potential to improve dancers’ balance control.

Neuropsychologia 2019 Jun:129:318-330.

Improved balance performance accompanied by structural plasticity in blind adults after training

Ann-Kathrin Rogge ¹, Kirsten Hötting ², Volker Nagel ³, Astrid Zech ⁴, Cordula Hölig ⁵, Brigitte Röder ⁶

Abstract

Postural control requires the sensory integration of visual, vestibular, and proprioceptive signals. In the absence of vision, either by blindfolding or in blind individuals, balance performance is typically poorer than with sight. Previous research has suggested that despite showing compensatory vestibular and proprioceptive processing during upright standing, balance performance in blind individuals is overall lower than in sighted controls with eyes open. The present study tested whether balance training, which places demands on vestibular and proprioceptive self-motion perception, improves balance performance in blind adults, and whether we find similar structural correlates in cortical and subcortical brain areas as have been reported in sighted individuals. Fourteen congenitally or late blind adults were randomly assigned to either a balance or a relaxation group and exercised twice a week for 12 weeks. Assessments prior to and after training included balance tests and the acquisition of T1-weighted MRI images. The blind balance group significantly improved in dynamic, static, and functional balance performance compared to the blind relaxation group. The balance performance improvement did not differ from that of age- and gender matched sighted adults after balance training. Cortical thickness increased in the left parahippocampus and decreased in the inferior insula bilaterally in the blind balance group compared to the blind relaxation group. Thickness decreases in the insula were related to improved static and functional balance. Gray matter volume was reduced in the left hippocampus proper and increased in the right subiculum in the blind balance group. The present data suggest that impaired balance performance in blind adults can be significantly improved by a training inducing plasticity in brain regions associated with vestibular and proprioceptive self-motion processing.

Gait Posture 2016 Mar:45:143-50.

Whole-brain grey matter density predicts balance stability irrespective of age and protects older adults from falling

Matthieu P Boisgontier ¹, Boris Cheval ², Peter van Ruitenbeek ³, Oron Levin ³, Olivier Renaud ², Julien Chanal ⁴, Stephan P Swinnen ⁵

Abstract

Functional and structural imaging studies have demonstrated the involvement of the brain in balance control. Nevertheless, how decisive grey matter density and white matter microstructural organisation are in predicting balance stability, and especially when linked to the effects of ageing, remains unclear. Standing balance was tested on a platform moving at different frequencies and amplitudes in 30 young and 30 older adults, with eyes open and with eyes closed. Centre of pressure variance was used as an indicator of balance instability. The mean density of grey matter and mean white matter microstructural organisation were measured using voxel-based morphometry and diffusion tensor imaging, respectively. Mixed-effects models were built to analyse the extent to which age, grey matter density, and white matter microstructural organisation predicted balance instability. Results showed that both grey matter density and age independently predicted balance instability. These predictions were reinforced when the level of difficulty of the conditions increased. Furthermore, grey matter predicted balance instability beyond age and at least as consistently as age across conditions. In other words, for balance stability, the level of whole-brain grey matter density is at least as decisive as being young or old. Finally, brain grey matter appeared to be protective against falls in older adults as age increased the probability of losing balance in older adults with low, but not moderate or high grey matter density. No such results were observed for white matter microstructural organisation, thereby reinforcing the specificity of our grey matter findings.