Walking Gait Cycle

1
Walking Gait Cycle

• Walking Gait Cycle - 6040 stance to swing phase
• Stance Phase (IC) LR MS TST PSW
• LR beginning of 1st double support phase
• MS foot is in full contact adapting to
  envt,
  
• beginning of single support, which is of
  equal
  
• duration of contralateral swing phase
• TST foot is preparing to toe off (TO)
• PSW 2nd double support phase
• Swing Phase begins with TO and ends w/ IC
• ISW MSW - TSW

2
Running vs. Walking Gait Cycles

• The Running Gait Cycle has a temporal reversal of
  StanceSwing phases (4060) as compared to
  Walking Gait Cycle (6040) the stance phase
  during sprinting may be as low as 22 of cycle
• Stance Phase Absorption (Mid stance)
  Propulsion
  
• Swing Phase ISW (75) (MSW) - TSW (25)
• Running Gait two periods of double float in
  swing refers to when neither foot is in contact
  w/ the ground at the beginning and at the end of
  each running swing phase
• Walking Gait two double support periods in
  stance
  

3
Float vs. Support
4
Running Gait Cycle

• Step length IC of one foot to IC of the 2nd
  foot
  
• Stride length IC of 1st foot to IC of the same
  foot
  
• Cadence number of steps in a given time on
  average about 100-122 steps/min with females
  averaging about 6-9 s/m higher
  
• As running Velocity increases, there is an
  initial increase in step length, followed by
  increased cadence
  
• Stride length is limited by runners leg length,
  height, and ability generally the longer the
  stride, the higher the velocity
  
• When optimum stride length is attained further
  velocity increases will come from increased
  cadence

5
Kinematics

• Kinematics of Walking and Running are much
  different
  
• There is an increase in joint ROM with increasing
  velocity
  
• Virtually no difference is found in the
  transverse and frontal plane kinematics with
  most of the difference occurring in the sagittal
  plane
• Lower C of G
• Increased speed due to increased flexion of hips
  and knees and increased dorsiflexion of the ankle

6
Knee Kinematics of Running

• The knee demonstrates increased flexion with
  increasing velocity, but as seen with the hip,
  extension decreases
  
• Absorption phase of the stance phase sees knee
  flexion to accommodate ground reactive forces
  walking only requires about 10 deg of flexion
  vs.35 during running
• Max knee flexion occurs at MS, after IC, during
  the absorption phase this is followed
  sequentially by knee ext max knee flexion during
  walking occurs just after TO
• Avg. Knee ROM is 63 deg during Running and 60 deg
  during walking the major difference is that max
  flexion during walking only reaches an avg. of 64
  deg, whereas during running it reaches an avg. of
  79 deg. conversely, knee extension is on
  average, 10 degrees less during running than
  during walking
• (-16 deg. vs -6 deg).

7
Hip Kinematics of Running

• Flexion of the hip increases, as extension of the
  hip actually decreases with increasing velocity
  
• One study of walking found overall ROM of 43 deg,
  with 37 deg of flexion and 6 deg of ext this
  study also found an increased ROM during running,
  with overall ROM averaging 46 deg, all of which
  was hip flexion with the hip never reaching
  neutral (negative extension)
• Max hip ext occurs at TO Max hip flex occurs at
  TSW

8
Ankle and Foot Kinematics

• Ankle joint primary plantar/dorsiflexor
• Foot joints including subtalar, oblique
  midtarsal, longitudinal midtarsal and 5th ray
  provide for tri-planar pronation/supination
  
• Pronation dorsiflexion/eversion/abduction
• Supination plantarflexion/inversion/adduction
• Metatarsalphalangeal joints (MTP) are biplanar
  mostly dorsiflexion/plantarflexion w/ some
  abd/add
  

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Foot Osteology
10
Ankle and Foot Kinematics cont.

• Walking ankle plantarflexes after IC and during
  LR, followed by dorsiflexion at MS overall ROM
  is approx. 30 deg (18 plantarflex/12dorsiflex)
  
• Running overall ankle ROM of 50 deg
• At IC (rearfoot in most), ankle undergoes rapid
  dorsiflexion during absorption (pronation)
  
• Supination is limited due to diminished time of
  plantarflexion, and pronation is increased
  
• May lead to excessive pronation injuries
• Running shoes or orthotics may limit this
  excessive pronation, and allow for more
  supination, and thus a more rigid foot for
  propulsion
• A pronated subtalar joint allows the foot to
  become the mobile adapter whereas a supinated
  subtalar joint serves to lock the midtarsal
  joints, creating a rigid lever to better serve
  propulsion

11
Overpronation
12
Windlass Mechanism
The plantar fascia and the intrinsic foot muscles
increase the efficiency of propulsion by
providing spring-like support to the medial
arch of the foot, helping to deliver the foot
into supination, and contributing an elastic
tension.
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Windlass Mechanism (cont.)
14
Lower Extremity Kinematics of Running

• At IC, the pelvis, femur and tibia begin to
  internally rotate int. rotation lasts through LR
  until MS this everts and unlocks the subtalar
  joint, oblique and longitudinal midtarsal joints
  and in turn absorbs shock (pronation)
• External Rotation of the pelvis, femur and tibia
  begin following MS, causing inversion and
  subtalar and mid foot locking, creating the rigid
  lever for propulsion
• All lower extremity joints work together during
  walking/running to provide a biomechanically
  efficient means of locomotion
  
• These joints depend on each other and upon
  muscular action to carry out walking or running

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Lower Extremity Kinematics of Running (cont.)

• Metatarsal Break-
• the oblique line drawn across the metatarsal
  heads. This oblique axis promotes hind foot
  inversion during toe off, which contributes to
  external rotation of the entire stance leg

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Lower Extremity Kinematics
17
Lower Extremity Kinetics

• Kinetics the study of forces that cause
  movement, both internally (muscular) and
  externally (ground reactive forces)
  
• As compared to walking, running increases muscle
  activity in all muscles
  
• Ground reactive forces measured with a force
  plate system demonstrates that vertical
  reactive forces are the most significant in
  running
• In rearfoot or heel strikers (80 of runners),
  there is a two-bump force plate appearance with
  one occurring in the rearfoot during loading
  response and one in the forefoot during
  propulsion
• Walking produces GRF of 1.3-1.5x body weight
• Running produces GRF of 3-4x body weight

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Clinical Note

• Running injuries typically occur as a result of
  volume training
  
• With 3-4x body weight with each impact, 50-70
  steps per foot per minute, 300-900 times per
  mile, the cumulative load can be measured in
  tons
• Stress fractures occur as a result of high volume
  training, combined with inadequate rest and
  recovery and/or biomechanical flaws
  
• Observed running injuries often occur at sites
  that mirror areas of peak force plate measures
  
• Placing a runner in a cushioning shoe may
  minimize peak force however, the extra shock
  absorbing materials built into the midsole may
  result in excessive pronation in some runners,
  both due to less restriction of pronation and
  possibly due to increased moment arm on which
  GRFs act

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Stress Fractures
20
Running Economy

• Measured in terms of Submaximal Metabolic Energy
  Expenditure (VO2submax), running economy is a
  method by which running biomechanics are studied
  to determine their affect on running performance
• It is hypothesized that some variations in
  economy might be due to differences in genetic
  factors that cannot be changed through technique
  adjustments or training
• Other factors that are thought to contribute
  include motor unit recruitment, anatomical
  mechanical advantage and movement skill

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Factors and their Positive Effect on Running
Economy

• Vertical oscillation
• Pronation
• Trunk lean
• A-P Impulse
• Plantarflexion
• Knee Extension
• Plantarflexion velocity
• Arm motions
• Vertical Force
• Hip Extension
• Stride Length
• Stride Index

HIGH
VO2
LOW
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Running Economy (cont.)

• It is likely that Running Economy is directly
  effected by running mechanics
  
• However, it is not known how much running
  performance can be enhanced by altering a
  runners technique or style
  
• Many running related movement patterns that may
  seem uneconomical or sub-optimal may be as a
  result of an adaptation to a structural or
  functional anomaly where alteration of that
  pattern may diminish economy and/or increase risk
  of injury
• External factors that can influence economy
  include shoe weight, midsole composition, wind
  velocity, materials and slope of running surface.
  These have been identified and are relatively
  easy to measure.
• Identifying running styles or techniques that can
  predictably result in economy changes is very
  difficult

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References

• OConnor, F and Wilder, R (2001). Textbook of
  Running Medicine, McGraw Hill.
  
• Neumann, D.A. (2002). Kinesiology of the
  Musculoskeletal System. St. Louis, Missouri.
  Mosby.
  
• McGinnis, P.M. (2005). Biomechanics of Sport and
  Exercise 2nd ed. Champaign, IL. Human Kinetics.
  
• Cavanagh, P.R. (1990). Biomechanics of Distance
  Running. Champaign, IL. Human Kinetics