Research Bites Vol. 1
For all of you who missed my research posts on my Instagram (@science_of_falling), welcome to Research Bites. 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 paper entitled, "Effect of neck flexor muscle activation on impact velocity of the head during backward falls in young adults" by Choi, et al., it was found that decreased impact velocity of the head during a backwards fall is correlated with increased SCM activation.
Study Details
🔸8 participants (3 males/5 females)
🔸19-35 yo
🔸Participants reenacted backwards falls of older adults as seen on video recordings from LTC facilities
🔸Fell from standing to 30cm thick mat
🔸Self-initiated fall with wrist guards and helmet
🔸3 trials each with differing level of head impact: no impact, soft impact, hard impact
🔸Fall data captured with 10 camera motion analysis system, and SCM EMG
Study Findings
🔹SCM activation 69.4% ⬆ in "no impact" trials over "hard impact" trials
🔹Vertical impact velocities 87% greater in "hard impact" trials over "soft impact" trials
🔹Horizontal impact velocities 83% greater in "hard impact" trials over "soft impact" trials
🔹These impact velocities ⬇ with ⬆ SCM activation
🔹For every 10% ⬆ of %MVIC of SCM activation the vertical impact velocity ⬇ 0.24 m/s and horizontal impact velocity ⬇ 0.22 m/s
My Take 🤓
Although this was a small study performed on younger populations, it gives weight to having neck training in a fall risk prevention program. Specifically, neck flexion training. If we can avoid or reduce head impact during a fall, we can avoid potentially life threatening head trauma. You can try performing the Neck Flexor Endurance Test on your fall risk patient to get a baseline strength/endurance value. Then have them perform this exercise to improve activation of the SCM and cervical flexors as needed.
In a study entitled, " Martial arts fall techniques decrease the impact forces at the hip during sideways falls" by Groen, et. al. It was found that properly performed sideways martial art techniques reduce hip impact ipsilaterally by 25%+. 🥋
Study Details
🔸Participants 6 judokas
🔸Ages 24.2 +/- 3.8 years
🔸Average martial arts experience 13.0 +/- 6.8 years
🔸Force plates and 6 camera mocap system to determine impact velocity and impact force
🔸Utilized 3 different falling techniques: block fall (control), martial arts fall with arm use, martial arts fall without arm use
Study Findings
🔹Largest mean hip impact forces and velocities occurred during the block fall
🔹Both martial art falling techniques reduced hip impact force by 27% and 29.5% respectively compared to the block fall
🔹Impact velocity also significantly reduced in both martial art techniques
🔹No significant difference between martial arts techniques were seen
My Take 🤔
Based off the findings in this one study, martial art falling techniques to the side may help reduce hip impact and thus hip fractures in both old and young. Although hand use did not seem to impact how the hip was affected during a fall, use of the hands during a fall may help protect the head and shoulders.
Although not always practical in sport, a study entitled, "Falling as a strategy to decrease knee loading during landings: Implications for ACL injury prevention" by Li, et. al. found that forces that lead to ACL injuries can significantly be reduced during landings by immediately performing a skilled fall forwards or backwards.
Study Details
🔸Participants:16 male/16 female recreational athletes
🔸Age 22yo +/- 2.9 years
🔸Performed 3 different landing types: natural, soft, landing with a fall (roll to shoulder); forward and vertical jump variations; single and double leg variations
🔸Force plate, retro-reflective markers, and 10 camera capture system used for data collection
Study Findings
🔹Soft landings and roll landings significantly increased the amount of force safely absorbed compared to natural landings
🔹In part, this was due to increased knee flexion angles which allowed more time for absorption
🔹Double leg trials were also found to be more efficient at reducing force due to increased ability for a deeper knee flexion angle
🔹Single leg landings had shallower knee flexion angles due to limitations in strength and thus much smaller force difference between natural and soft landings compared to double leg landings
🔹Performing a fall in all scenarios reduced forces known to injure the ACL, although most significantly in the single leg landings
My Take 🤓
Although it may seem counterproductive to fall after landing, especially in sport, learning to fall can add longevity to a sports career. Single leg landings seem to be harder to control secondary to limitations in leg strength. In contact sports, falls are often awkward in the heat of the game. Learning to safely fall after an awkward landing may allow an athlete to stay in the game instead of tearing an ACL and being out 6+ months. Training appropriate fall techniques should be considered an essential injury prevention exercise, as well as a way to help athletes recover quicker from stumbles on the court.
My second take is to train deep single leg movements. Gain stability and control to allow deeper knee flexion angles and create a spring like effect.
A study entitled, "Kinematic Analyses of Parkour Landings From as High as 2.7 Meters" by Dai, et. al. showed that vertical and horizontal landing velocities were maintained to a higher degree during a shoulder roll landing as compared to the squat, stiff, and forward landings. This means that less force was absorbed through the body per second, allowing greater force dispersion, and thus potential decreased injury risk from a fall.
As a side note, this study showed lots of quality nuggets into landing mechanics and velocity changes. I will mainly be focusing on the shoulder roll findings.
Study Details
🔸Seventeen male parkour practitioners age 23.9 +/- 4.7 yrs; Three female parkour practitioners age 26.2 +/- 1.3 yrs
🔸Male training experience 7.1 +/- 2.3yrs; Female training experience 4.7 +/- 2.5 yrs
🔸Participants were from @apexsom
🔸Performed 4 landing techniques (stiff, squat, forward, and shoulder roll) from 3 heights (.91m/3ft, 1.83m/6ft, 2.74m/9ft)
🔸Stiff landing not performed from 2.74m presumably for safety, and females did not perform the 2.74m drop
🔸High speed motion capture camera system used to film participants from sides and front for data collection
Findings
🔹The shoulder roll was found to maintain vertical and horizontal velocities to a higher degree in all scenarios than the 3 other landing techniques
🔹Stiff landings showed the greatest decrease in landing velocity over the initial 100ms of landing
🔹Roll landing demonstrated decreased peak knee and hip joint flexion compared to squat and forward landings
My Take 🤓
This study is fairly unique in its opportunity to study parkour landing techniques at significant heights. There is a lot to unpack in this study but the biggest finding is that the shoulder roll allowed a longer period of force dispersion by maintaining falling velocities in both the horizontal and vertical directions. Longer time for force dispersion = less force/s absorbed = lower injury risk.
When velocity is decelerated quickly, more force is consequently absorbed and increases the risk for injury. Thus when taking a big fall, a roll might be your safest bet.
A study entitled "Exercise-induced neuroplasticity: Balance training increases cortical thickness in visual and vestibular cortical regions" by Rogge et. al. showed that areas in the brain associated with memory and spatial cognition are increased with a balance program.
Study Details
🔸37 (# used for final analysis) relatively non-active subjects (less than 5 exercise sessions per month)
🔸Split between 2 groups: Balance Group (BG) or Relaxation Group (RG)
🔸Median age BG 43.9 yo; Median age RG 46.11 yo
🔸Both groups had roughly 21 training sessions of assigned method
🔸Balance training consisted of a circuit of balance exercises for 50min; Relaxation underwent classes in which they learned progressive muscle relaxation and autogenic training for 50min
🔸Training conducted over 12 week period
🔸Both groups underwent pre/post-experiment balance testing amd MRI imaging of their brain
🔸Test assessors blinded to participant group placement
Findings
🔹Between group balance ability did not differ before the experiment
🔹The balance of the BG increased after the experiment, RG did not
🔹MRI showed increased cortical thickness in the BG participants in the following areas: superior temporal gyrus, superior transverse occipital sulcus, superior frontal sulcus (left hemisphere), and posterior cingulate gyrus(right hemisphere) [these areas are all related to some degree in movement control, spatial cognition and memory]; RG did not show any significant changes as compared to the BG
🔹Improvements in balance performance were significantly correlated with increase in cortical thickness
My take 🤓
As has been found with other exercise types, training the body changes the brain. Although these brain regions increased as the BG undertook novel balance tasks, it is well known that the brain over produces nerve pathways when first learning a task. Long term MRI scans would most likely show a pruning of pathways, and thus subsequent cortical thickness shrinking, as the participant became more efficient. Therefore, balance exercises may have a slight neuro-protective and enhancing effect in those with declining mental acuity if given in a challenging manner.
Thanks for reading the first 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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