A perfect example of the concept of impulse.
To change the momentum of a falling body you can apply a smaller force for a longer time or a higher force for a shorter time.
Impulse is the area under the force time curve.
What is interesting is the psychological factor of people not wanting to be noisy when there is a quiet background.
The impulse you use to land from a fall is a sub conscious CNS choice.
It appears background noise is part of that choice.
This has implications for studies looking at vertical impact force peaks.
And maybe barefoot running.
Running quietly reduces ground reaction force and vertical loading rate and alters foot strike technique
Xuan Phan, Tiffany L. Grisbrook, Kevin Wernli, Sarah M. Stearne, Paul Davey & Leo Ng Sports Science 03 Sep 2016
The Relationship Between Landing Sound, Vertical Ground Reaction Force and Kinematics of the Lower Limb During Drop Landings in Healthy Males
Kevin Wernli et al
Interesting abstracts . So what would happen if you rigged a solid state accelerometer to a sound producing source and set the system to emit sound when impact transients are created during heel strike .
The accelerometer could be taped to the lower back area over the spine and the sound source could be a mobile phone located on the upper arm (I have seen people running with phones secured in this area so a suitable
product
probably exists )
.
The phone could be set to emit any number of noises and the effects studied .
Given the abstracts above I am fairly confident that if the phone was set to emit an embarrassing noise every time an impact transient was detected then
the study subjects would quickly learn to run without such transients whether
shod or unshod . This would be especially true if the subjects trained over time
in a busy public area .
Would the gait changes induced be a good thing . No idea
I feel that the issues around ground reaction forces and injury are clouded by the shod/ unshod debate .
If the system I have outlined above could be made to work then the relationship between
gait ,ground reaction forces ,and injury rates could be studied away from the barefoot debate
.
Just came across this from Prof Irene Davis . All the bits required for "gait change to avoid embarrassing noises" would therefore appear to be there . Who wants to quack like a duck all the way round Central Park ?
Would the gait changes produced be beneficial ?
Again ,I have no idea .
The use of multi-directional footfall sound recordings to describe running vertical impact properties
Cristina-Ioana Pirscoveanu & Anderson Souza Oliveira Journal of Sports Sciences : 05 Sep 2020