Test 4 Flashcards
A brief history of running shoes
-First doccumented footwear from ~10 000 year go
-Customized running shoes (1920s): Adi and rudi Dassler (brothers founders of puma and adidas)
-Cushinged running shoes (1960s): rubber sole ie nike and asics
What is the main purpose of running shoes?
-Protection/ reduction of high pressure areas on foot (psi= F/area)
-reduce impact peak and loading rate of ground reaction forces
-Improve stability and control (bore-motion control-neurtral)
Note on motion control shoes
overpronation was all the rage- combined fronal and tansverse plane rotation
Led to the development of motion control shoes- goal is to control and limit the amount of pronation occuring during running (and hopefuly correting subsevent int rotation of tibia and knee)
reality of motion control shoes
-Pronation is an important mechanism of the foot (to dissapate forces)
-Overpronation does not lead to injuries
-severe or extended pronation may still be an issue
Anatomy of a running shoe- upper
foot support and heel stabilizing
anatomy of a running shoe- midsole
-where most of the science happens
-shoc absorbtion, stability, motion control
anatomy of a running shoe- outsole
-rubber sole for traction and durability
2 key concepts of midsole design
-midsole tickness: aimed at absorbing and reducing rate of GRF
-Midsole stiffness: improved stability and or running perofrmance
Nike vapofly 4% (2017)
said to give runners an efficiency edge of 4.2% over other shoes
markergin campaign tied to a 2-hour marathon
-zoomX foam and carbon fiber plate
ZoomX foam
-Extra tick (31mm), but light weight
-compliant and resilient (85% engergy return)
carbon fiber plate
-stiffer midsole that acts like a lever or spring
-every brand is now deveoping a carbon fiber plate line– is this a form of mechnical doping?
Barefoot shoes- arguments for
humans have engaged in endurance running for millions of years but modern running shies were not invented until the 1970s
-there are anecdotal reports of reduced injuries in barefoot populations
Barefoot shoes are said to:
-improve proprioception and strength of foot, ultiately leading to improved stability and control
-reduce impact forces
barefoot vs shod; compaing apples to apples impact forces
reducing cushion would not reduce impacts
barefoot vs shod not appples to apples
Complex interaction between foot strike, cadence, and impact forces
-10% reduction in stride lengthen can lead to 5% reduction in joint forces
-Barefoot strike pattens have longer stide lengthes than mid or forefoot strike patterns
-running wothout cushion (ie barefoot) pushes people away from a rearfoot strike pattern
Is barefoot better for reducing injuries?
-One study followed 100 barefoot and 100 shod runners for a yeat
-Barefoot had more ankle/foot injuries (load taken up by the foot/ankle)
-Shod had more knee and hip injuries (more laod taken by the knee)
-Non significant- barefoot had more injuries per 1000miles (lots of variability)
-More injuries in shod rnners when look at all (but need to consider they were able to run more- likely why you have more injuries)
barefoot vs shid reccomendation
the comfort filter: runners should select the most comfortavle shoes for their movment pattern
changing stike pattern cannot be recommened for an uninjuried rear foot strike runner
** location of strike matterns more than rate: a runner with knee pain Iand a hard rearstrike) may benifit from a higher cadence, shorter stride pattern, but should be mindful of foot and achilles pain
barefoot vs shod take homes:
-different movement patterns will always exist and trying to “correct” may not be warranted (especially if there is not pain)
-simply put finding a comfotable shoe and managing training load may be the most important factor.
How do inertial sensors factor into all of this?
Inertial sensors are excellent at measuring the impact peak (tibial shock), cadence, ect
-impact often measured as the vertical or resultant peak on the tibia
Can be useful in comparing groups, tracking changes, providing rea-time feedback, or maybe even footware prescription.
External load
-Objective measure of the work performed by an athelte during trianing or competion
— distance, speed, resistance, reps, ect
Internal load
-the internal response to he external load
—Physiological(eg HR, blood lactate, EMG, ect) or psychological (eg RPE)
-very individual
from a mechanical perspective: Load relaives to the physical stress (or force) placed in an object
-Stress-strain curve
-Mechanical load causes tissues to remodel
-Injuries= mechanical load> strength of tisue
—Acute injury (ie fracture, complete tear)
—Chronic injury (eg microtears, tendinitis, stress fracture)
Tibial sensor acclerations as internal?
The acceration rate to waht the msk system is exerpeincing for a given activity
Impact load as a proxy for internal load
-may be related to or predictive of in vivio bone stress strain
Only measuring at tibia
-May be affected by technique, lower limb stiffness, footwear
Emvelop of function
Health of the system
Goldilocks trianing zone
-Over: acute, chronic injury
under: detraining, loss of bone/ muscle tissue
Assymmertry
Hamans are not symmertrical
-Anatomically, strength, ROM, coordination, ect
>10% between limb differences are thought to be dterimental to performance and potentially related to injury
-assymetries are highly variable, task-specific, and difficult to objectively standard cut off
-Measuring, tracking and investigating the underlying mechanisms are still important
Quantifying assymetry
many ways to quantify asymmetry
-impact acclerations (impact load) is just one
envelop of function- assymetry
Both magintude and frequency can be different between limbs in an activity
-sport relies more on one side
-atheltes utilize one side more
-chronic pain in one limb
Case study: assymert- virgina tech soccer
collected impact data pre and post ACL inurt
-see that ahtelte had an extreme case of not doing anything at high intensity in the previously inureed leg (increased risk of injury for RTS if go full out in a game)
Inertial sensors in running and sport
new are with much to learn
limited prosective studies but massive amounts of data are being generated
Inertial sensors in running and sport -scientific comupting necessary to:
-Manage large amounts of incoming data
-efficiency and accuretly process the data
-derive meaningful insights and visualizations
