Research Bites Vol. 2
Welcome back for another installment of Research Bites! For all of you who missed my research posts on my Instagram (@science_of_falling), you came to the right place. Every few weeks I will be posting a new set of five quick and dirty research reviews with the main findings, how it was performed, and my quick take on it.
The trick is, I only have the space of an Instagram caption (2200 characters) to dive in and extract main points. It makes for a fun challenge! If you want to see these posts sooner, head on over to Instagram and hit that follow button.
Enjoy that tasty research!
In a study entitled, "Low Bone Mineral Density is Associated with Balance and Hearing Impairments" by Mendy et. al., researchers sought to discover if low head and total bone mineral density (BMD) was correlated with postural balance and hearing impairments.
Study Details
🔸Data was analyzed from the 1999-2004 National Health and Nutrition Examination Survey (NHANES)
🔸The study utilized participant data that contained all of the following: BMD, balance testing, hearing status, and relevant covariates
🔸Total participants included in the final analyzation as 8863, ages 40-85 yo (mean 57yo +/- 13 years)
🔸Balance assessed via Romberg Test of Standing Balance on Firm and Compliant Support Surfaces (RTSBFCSS) [Essentially the 4 stage CTSIB-M]
🔸Hearing status was obtained via survey on a 3-pt scale
🔸BMD evaluated via dual energy x-ray absorptiometry
Study Findings
🔹Lower BMD correlated to higher chance of failing condition 4 (Vestibular function focused) of the RTSBFCSS, especially if over 65+
🔹 Lower total BMD and head BMD were correlated with higher chance of reporting hearing trouble
My Take 🤔
Although this study is not perfect, it certainly makes sense that low BMD would correlate with a harder time balancing (presumably from vestibular dysfunction) as well as hearing deficits. After all, the vestibular/hearing systems are encased by the bony labyrinth. If BMD decreases, these two intertwined systems will inevitably change and result in a weaker structure. I'm definitely interested to see more studies down this line of research.
A study entitled, "Ankle Dorsiflexors Strength Improves Balance Performance in Elderly: A Correlational Study" by El-Kader et. al. explored whether or not dorsiflexor training could enhance balance ability.
Study Details
🔸50 healthy older adults ages 65-75 years old
🔸Evenly split into two groups: Control (no training) group and Training group
🔸Both groups underwent pre/post-experiment testing including: hand-held dynamometry testing of dorsiflexor strength, Berg Balance Scale (BBS), Functional Reach Test (FRT), Timed Get Up and Go (TUG)
🔸Testing done before and after 8 week period
🔸Control group encouraged to continue normal daily activities
🔸Training group underwent 3x/week training of dorsiflexors in addition to electrical stimulation of the same muscles
Study Findings
🔹Significant mean changes were found in the training group including:
↪BBS ⬆12.9%
↪FRT ⬆ 35.7%
↪TUG time ⬇51.9%
↪Dorsiflexor strength from 12.33kg➡18.73kg
🔹No significant changes were found in the Control group
My take 🤔
Strengthen those dorsiflexors people! Calf work is almost always addressed during therapeutic or athletic training, why not the dorsiflexors? If strong dorsiflexors have a correlation with better balance, there is no reason to leave toe raises out of a strengthening or balance program. Raise them toes!
A study entitled, "Balance Recovers Within 20 Minutes After Exertion as Measured by the Balance Error Scoring System" by Susco et. al. Set out to determine a balance recovery timeline in college-aged individuals after a functional exercise protocol.
Study Details
🔸100 active college students
🔸Average age 21yo
🔸Split into 5 groups (1 control, 4 experimental); Control, Test 0, Test 5, Test 10, Test 15 (numbers represent how many minutes of rest was given before Post-test 1)
🔸Underwent 3 balance trial periods using the Balance Error Scoring System (BESS); Pretest (before exertion), Post-test 1 (at a predetermined time after exertion signified by group number), Post-test 2 (after 20 minutes of rest for all groups)
🔸BESS: an objective sporting sideline postural stability assessment tool utilizing 6 conditions with 3 foot positions (double leg, single leg, tandem) and two surfaces (compliant and non-compliant). Higher scores = more balance errors = balance deficits
🔸All groups, except for control, underwent a 20 min exercise program consisting of 7 stations. With sufficient Rate of Perceived Exertion (RPE) goal of 15+ at end of exercise. Control rested for 20 minutes.
Study Findings
🔹Control testing scores showed no large significant differences during any of the BESS trials
🔹All experimental groups had worse Post-test 1 scores than Pretest and Post-test 2 scores showing a drop in balance performance after exertional exercise
🔹Longer rest periods resulted in slightly better balance performance, especially in the Test 15 group, but still worse than Pretest values
🔹Pre-test and Post-test 2 scores were statistically the same showing that balance performance returned to baseline for all groups at the 20 min rest mark
🔹Fatigue and reduced rest time affected single leg conditions the most
My Take 🤔
This 20 minute mark has been a consistent finding in various research papers to date. I believe we can utilize this window in two ways. #1 let a patient rest for 20 minutes before balancing for optimal performance. #2 train balance in the 20 min window to create adaptation during a fatigued state for sports such as OCR.
A study entitled "Balance Performance and Recovery After Exercise with Water Intake, Sport Drink Intake, and No Fluid" by Erkmen, et. al. set out to determine the effects of fluid intake on balance performance post exercise. As a side note, in past studies it has been found that balance performance is decreased for 20min post exertional exercise. (Susco 2004)
Study Details
🔸Seventeen physically active males
🔸Age 22.29 +/- 1.61 yo
🔸Underwent 1 hour exercise session on treadmill 75-85% MHR
🔸Each subject underwent this exercise session under three conditions: No Fluid (NF), Water (W), Sport Drink (SD [Powerade])
🔸3 days given for recovery between each condition
🔸Before and after NF session subjects weighed to determine fluid loss; this weight difference determine fluid intake amounts per athlete
🔸In drinking conditions subjects drank pre-measured amount every 5 mins
🔸Balance performance tested using the Biodex Balance system in single leg, eyes open (EO) & eyes closed (EC) conditions
🔸Tested 3 times: Before exercise, post-exercise, after 20 min recovery period
Findings
🔹Body weight dropped roughly 2.17% in NF pre to post exercise; Fluid intake conditions had no significant change in weight
🔹In NF, post-exercise balance was significantly worse than pre/recovery
🔹Fluid intake of both types showed no significant drop in balance performance at any period
🔹In all conditions, balance recovered back to pre-exercise levels by 20 mins
🔹No significant differences were definitively found between W and SD intake
My take 🤔
I think this study hits a common theme in the exercise field home. Fluids equal better performance. Additionally, I think we can also deduce that if a dehydrated athlete were to continue playing after this study's 1hr limit, the reduced balance ability would reduce overall athletic performance. Point being, drink your fluids!
A study entitled “Higher Visual Reliance During Single-Leg Balance Bilaterally Occurring Following Acute Lateral Ankle Sprain” by Kim, et. al. set out to see if visual adaptation for balance occurs immediately after an acute lateral ankle sprain (ALAS).
Study Details
🔸53 subjects (27 with ALAS, 26 healthy); matched for age, height, mass, and sex
🔸ALAS group recently injured (24-72 hours)
🔸Participants performed 3 trials of postural task lasting 10s each
↪Double leg balance (DLB) eyes open (EO) and eyes closed (EC)
↪Single leg balance (SLB) EO and EC
🔸Order of balance testing randomized
🔸Forceplate used to assess sway during testing
🔸Time-to-boundary (TTB) measures taken each trial (mean and standard deviation [SD])
↪TTB Mean = estimates the minimum time the individual has to make a postural adjustment before losing balance
↪TTB SD = quantifies the complexity (variability) of the postural control systems
↪ Both assessed in anteroposterior and mediolateral directions
🔸Using TTB, researchers calculated amount of visual reliance in each subject in regards to balance
Study Findings
🔹ALAS group presented higher declines in SLB bilaterally from EO to EC conditions than uninjured group
↪Indicates higher visual reliance for both injured and non-injured limbs
🔹ALAS showed greater visual reliance in DLB as well
My take 🤓
This study found that a ALAS in one limb can negatively affect balance in the non-injured limb as well. This is most likely due to a CNS downregulation of somatosensory input increasing the need for visual cues to maintain balance. So if you roll an ankle, it is imperative to work both limbs equally, and train sensory heavy balance exercises to help normalize the brains sensory perception of both limbs. The brain never ceases to amaze me!
Thanks for reading the second volume of Research Bites! I hope you learned a tidbit or two. Be sure to follow my Instagram account to see these research bites right away, and comment below on what you think about the findings above.
Happy Falling!
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