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Biomechanics of Walking and Running

KIN 311 - Berry College - Dept. of Kinesiology
by

David Elmer

on 26 March 2017

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Transcript of Biomechanics of Walking and Running

gait cycle
range of motion will increase with increasing speed
speed = stride length x stride frequency
dynamic optimization
human walking is optimized to minimize energy consumption
the loss of one of the 6 main components of walking will result in a reduction in efficiency
1. pelvic rotation
2. pelvic tilt
3. knee flexion
4. hip flexion
5. knee-ankle interaction
6. lateral pelvic displacement
non-sagittal movements:
pelvic rotation
pelvic tilt away from support leg
hip internal and external rotation
hip adduction and abduction
gait cycle
hip
knee
ankle
slight flexion
slight flexion
plantar flexion
extension
extension
dorsiflexion
extension
flexion
plantar flexion
flexion
flexion
dorsiflexion
slight extension
extension
dorsiflexion
upper body:
anti-phase, contralateral arm swing
reduces net angular momentum
Walking
Running
&
repeatedly losing balance and regaining support
negative factors:
pathology, age, and obesity
positive traits:
alignment of lower extremities and weight-bearing segments
limited lateral movement
normal flexibility
properly functioning reflexes

transitions from braking to driving phase normally occur between 45-50% of stance time
variations suggest an abnormal gait
GRF varies depending on foot strike and pronation
heel strike - land on rear 1/3 of foot -
mid-foot strike - land in middle 1/3 of foot
fore-foot strike - land on front 1/3 of foot
which is best?
Lieberman, et al. 2010
published in
Nature
forces
economy
heel
mid-foot
foot strike
heel strikers significantly more economical
Ogueta-Alday et al. 2014
mid and fore foot striking - potential to reduce risk of injury
Hatala, et al. 2013
Daoud et al. 2012
so barefoot running is the answer, right?
not exactly
habitually barefoot runners heel strike at slower speeds and mid-foot strike at higher speeds
80% of runners
pronation is a normal and necessary component of the support phase
rapid rotation at the subtalar joint from inversion to eversion
necessary for shock absorption
simultaneous eccentric action of plantar fascia
accompanied by internal rotation of the tibia
range of pronation > 20 deg = excessive rotation of the tibia
alters loading at the ankle
may lead to knee pain, especially if a long time is spent in an excessively pronated position during the support phase
tibia rotation affects alignment in knees
amount of pronation affected by body weight and running speed (both increase it)
initial speed gains are due to increased stride length
at higher speeds, increased speed primarily due to increased frequency
so pronation is bad too, right? well... maybe?
Haille Gebrselassie - former marathon world record holder
stance phase
swing phase
Same general phases as walking, but no double support
sagittal
Q-angle
varus vs. valgus
plantarflexion
dorsiflexion
flexion
extension
flexion
extension
Full transcript