Research Bites Vol. 7
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!
A study published in 2014 by Duffell et. al. investigated how early knee osteoarthritis (OA) affects balance and gait.
Study Details
🔸18 subjects with clinical and radiographic evidence of unilateral early medial knee OA
-All subjects had presented to healthcare clinics with OA symptoms
-At time of testing all subjects denied having pain/swelling and could ambulate without the use of an AD
🔸All testing subjects matched with control subjects (same sex and age [+/- 7 years]) who had no signs of OA
🔸Control and OA subjects had a mean (SD) age of 56.2 (13.0) and 56.4 (12.4) years, height of 1.68 (0.09) and 1.68 (0.11) m, and weight of 68.1 (13.7) and 75.1 (12.5) kg, respectively
🔸Force plate data during walking and standing trials, electromyographic (EMG) data of the lower extremities, motion capture data of gait, and maximal voluntary isometric contractions (MVICs) of the lower limb musculature taken for analysis
-Subjects walked 6m x 5 trails over force plates, then asked to stand still for 30s on force plate in 4 conditions: eyes open double leg (EODL), Eyes closed double leg (ECDL), single leg on left (SLOL), single leg on right (SLOR)
Study Findings
🔹No significant differences between the control and OA subjects for all kinematic and kinetic parameters measured during gait
🔹Sway was no different between groups during EODL and ECDL, but OA group had increased sway in both SL scenarios on the affected and unaffected sides
🔹During SL standing OA group showed increased activation of the glutues medius (GM) on the ipsilateral (same) side they were standing on in both the affected and unaffected sides
-This also occured on the unaffected side during EODL trials
🔹OA group showed greater activation of both the quadricep (QP) and hamstring (HM) during SL stance on the affected side only
My Take 🤓
This study showed that those with early OA have altered muscle activation of the GM, QP, and HM. This altered activation may be the cause of the OA group showing increased postural sway in both SL conditions. Overall, it would be wise to assume increased postural sway may be present if a subject has knee OA no matter the stage of the pathology
A study presented as a poster and published in the Journal of Sport Sciences by J. Adams in 2021 delved into how varying landing mechanics during parkour vaults affected ground reaction forces (GRF).
Study Details
🔸10 parkour practioners: age: 29.4 ± 7.18 years, experience: 9.7 ± 3.62 years
🔸Subjects performed 1 baseline and 3 vault variations: drop landing (baseline), step vault, dash vault, kong vault on .96m x. 55m vault box
🔸Two landing types for each: two-foot precision landing, and single foot running landing
🔸All trials performed onto a force plate to measure Vertical GRF (vGRF) and braking GRF (bGRF)
-24 trials performed in total
Study findings
🔹All movements showed increased vGRF when using a running landing vs a precision landing
🔹Kong vault showed highest vGRF and bGRF in both landing styles
🔹Dash vault conversely showed the least vGRF and bGRF of all the vault styles
-significant difference noticed in running landing, but not precision landing
🔹Step vault showed no significant difference when compared to the drop landing in either landing style
My Take
If you have been following me any length of time you may know that a large part of the idea for SoF came from my experience in Parkour. Parkour landing techniques and ukemi techniques are specifically adapted to create safe movement in the modern concrete world. Vaults and jumps are essentially controlled falls that may or may not go to the ground. On the rare occasion parkour research is published, I always like to check it out.
With that being said, it is quite interesting to see how each vault variation/landing variation changes the amount of GRF, of which correlates with how much force goes through the body itself. This study essentially gives weight to the effectiveness of the landing techniques taught in most parkour gyms across the world. It may also give individual coaches and practioners ideas of how to modify training when injured to reduce landing forces upon the body.
For a deeper look at this study with awesome breakdowns and visuals check out @parkourclinic 's blog post https://jmablog.com/research/pkvs/
A study published in 2015 by Cruz-Diaz et. al. evaluated the effects of six weeks of Pilates and passive Physical therapy (PT) vs passive PT alone, and their affects on fear of falling, function, and pain in community living women older than 65 years old with chronic low-back pain (CLBP)
Study Details
🔸6 week Single blind randomized controlled trial
🔸97 women 65+ with CLBP
-split into two groups randomly: 50 pilates + physical therapy (PPTG), 47 physical therapy only (PTG)
🔸Single blinded investigator performed all assessments for data collection:
-falls efficacy scale-international (FES-I) for fear of falling (FoF)
-Timed up and go (TUG) for functional ability and balance
-numeric rating scale (NRS) for pain
🔸Both groups underwent same PT protocol 2x/week, PPTG group had additonal pilates 2x/week
-PT consisted of 40 mins of electrical stimulation (TENS) and 20 mins of low back stretching
Study Findings
🔹FoF reduced significantly in the PPTG group after 6 weeks, no change in the PTG
🔹TUG test scores only improved significantly for PPTG but not for the PTG
🔹Both PPTG and PTG showed improvements in pain, but the PPTG had overall better results
My Take 🤔
This study is a bit iffy to me to be honest. The "PT" they used was only passive in nature with no strengthening used. In fact they called this "Physical Therapy", whereas in this post I made it clear they only used "passive PT".
I don't think this can truly be called PT at that point, and the study definitely misrepresents the what PT is. True PT includes active exercises just like Pilates. Although Pilates seems to help those with low back pain, as per this study, I think it is the act of exercise rather than the Pilates itself. I would be interested to see this study be done with truly active PT and Pilates, rather than just passive modalities. Always read the fine print over a headline! 🤦♂️
A study published in 2015 by Han et. al. set out to determine if strength or power ability was a bigger player in preventing slip-related falls.
Study Details
🔸26 young adults (23.8 +/- 4.3 years)
🔸strength and power of right knee collected for all participants
-Strength values taken by determining joint torque under isometric contraction using a Biodex dynamometer chair system (BDCS) at 35 deg of knee flexion. Performed for 7 seconds for 3 trials. Avg maximum used for analysis
-Power values taken under isokinetic condition at three different speeds (60 deg/s, 120 deg/s, 180 deg/s) on the BDCS. 10 cycles performed for each speed. Avg peak power calculated ocer the 10 cycles for analysis
🔸Participants used ActiveStep treadmill to perform walking with slip perturbations for study
-Performed 5 normal walking trials of 10-12 steps at 1.2m/s, followed by a trial with a rapid reversal of treadmill direction and speed after an additional 10-12 steps to create a slip perturbation
-Full body kinematics captured using a motion capture system
-Body harness with load cells used for safety and fall data collection
-If the peak forces captured after a perturbation exceed 30% body weight, this was classified as a fall
Study Findings
🔹12 subjects fell (46.2%) and 14 subjects recovered (53.8) after the perturbation
🔹Knee strength capabilities not significantly different between groups
🔹Those who recovered showed, in general, significantly greater knee power capacity in 60 deg/s flexion and 120 deg/s extension/flexion trials
🔹Power measurements taken under 60 deg/s flexion and 120 deg/s flexion could predict a fall by 73.1%
My take 🤓
I have reviewed past articles saying strength is an important predictor in falls. This article implies power output may actually be more important.
💪 Power = strength x speed
As we can see strength is an important component of power, but it is not everything. Speed is just as important. So what's the takeaway from this study? I would say when training for fall prevention strength AND speed need equal attention for optimal outcomes. Doing this allows us to attack power from both angles. Don't forget light load high speed movements!
A study published in 2021 by Kirmizi et. al. set out to discover the balance deficit level present in those with chronic neck pain (CNP) under different sensory and dual task conditions.
Study Details
🔸️22 women with CNP and 22 women who were asymptomatic
🔸️Visual Analog Scale (VAS) and Neck Disability Index (NDI) used to assess pain and disability; ⬆️ scores in each correlate with ⬆️ pain and disability respectively
🔸️Biodex Stability System (BSS) used to collect stability index scores in two sessions (eyes open [EO], eyes closed [EC]) consisting of:
-Overall Stability Index (OSI)
-Anterior/Posterior Stability Index (APSI)
-Medio/Lateral Stability Index (MLSI)
🔸️⬆️ stability index scores show ⬆️ levels of instability
🔸️Each session consisted of 4 conditions performed in random order:
-Quiet standing
-Rotating head
-Counting backwards
-Standing on foam
🔸️All testing performed barefoot while upright on two legs, each session condition tested 2x for 20s with 10s rest between, 1 minute rest between sessions
Study Findings
🔹9 patients CNP (40.9%) had mild pain, 13 patients with CNP (59.1%) had moderate pain
🔹1 patient with CNP mild disability (4.6%), 18 patients with CNP moderate disability(81.8%), and 3 patients with CNP severe disability (13.6%) on the NDI
🔹Signifianct baseline effect on OSI, APSI, and MLSI with ⬆️ findings in the CNP group than controls, meaning more instability in CNP group
🔹CNP group had significantly ⬆️ OSI scores in all conditions except standing on foam with EO, quiet standing EC, and counting backwards with EC
🔹Largest effect size found during rotating head with EO
🔹️Neck pain intensity moderately correlated with OSI and APSI in quiet standing EO
My Take 🤔
CNP group showed less overall stability secondary to neck pain. In addition to this, dual tasking seemed to increase overall instability more in those with neck pain than in those without. This may be due to a disruption in cervical mechanoreceptor signaling, resulting in non-accurate information for the balance systems. The cervical spine, and cervical mechanoreceptors, are highly intertwined with the vestibular system.
Thanks for reading the seventh 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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