Week 7 Flashcards
Maximum efficiency for males
0.0072m/steps/min
Maximum efficiency for females
0.0064 m/steps/min
Speed formula
Step rate (cadence) x step length
Strategies to decrease energy expenditure (5)
Horizontal plane pelvic rotation Sagittal plane ankle rotation Stance phase knee flexion Frontal plane pelvic rotation Frontal plane hip rotation (step width)
Horizontal plane pelvic rotation does what
minimises hip flexion & extension for given length
Sagittal plane ankle rotation - does what
heel strike - ankle DF places calcaneus in contact with the ground, elongating the limb
End of stance (hip ext + knee flex) - lower extremity elongating lower limb
End of stance (hip ext +knee flex ) - lower extremity elongated via ankle PF
Function elongation decreases downward displacement of CoM
Knee flexion in stance phase does what
decrease upward displacement of CoM
Frontal plane pelvic rotation does what
stance phase = ipsilateral crest rises & contralateral iliac crest falls
(acts like a see-saw through gait cycle
Gait impacted by what clinical presentations (4)
Ankle disorders that decrease PFDF range
Knee disorders that impact on flex ROM and control
Inability to shift pelvis - frontal & sagittal plane
- consider link to LB and hip
-Need for increase base of support
Large muscle activity involves
eccentric contraction then concentric contraction
Result of EC-CC
Lengthening decelerates joint
subsequent shortening begin joint’s forward movement
At most joints, motion continues after concentric contraction ceases
Eccentric - concentric pattern =
Stretch - shortening cycle
- energy stored by stretched muscle released during muscle lengthening
- helps propel limb segment without additional contraction
Erector spinae (Lx) role during gait
control forward angular momentum of trunk relative to hips
Rectus abdominis role in gait
stabilises pelvis and Lx
Gluteus maximus role during gait
initiates hip ext + prepares for support of BW during stance
Prevents uncontrolled trunk flexion over the femur
- assists in knee flex indirectly
Largely inactive during swing
Hamstring role during gait
large activity duringfirst 10% for similar reasons to glute max
Iliopsoas role during gait
Active well before toe off
eccentric activity 30-50% as hip flexion before tow off
Remains active through initial swing decrease beyond 50%
– hip flexion continues by forward momentum of thigh
assisted by rec fem
Hip abductors role during gait
Frontal plane stability of pelvis
Stabilise pelvis over relatively fixed femur
control lowering of contralateral pelvis of swing limb
Generates compressive forces at the hip during stance phase
- produce force 2x BW to achieve stability during SL support phase
prevents excessive valgus
Glute med + min role in gait
most active in first 40%
glute med
-active at end of swing phase in prep for heel contact
anterior fibres also assist hip flex and IR
Posterior fibres also assist hip ext and ER
Quadriceps during gait
Active as group late swing phase
Major burst after heel contact to control knee flexion in first 10%
- shock absorption +prevents excessive flex
-concentrically to extend knee +take BW mid stance
Vastii role in gait
very active at heel contact
primarily shock absorbers
Rec Fem role in gait
primarily - transition from stance to swing
aids initiation of hip flexion +control of knee extension
May assist shock absorption at high walking speeds and running only
Hamstrings during gait (knee flex)
Most active just before to just after heel contact
Decelerates knee extension preparing for ground contact of foot
Initial 10% stance
- assists active hip ext
-co-contraction to stabilise knee
Triceps surae function during gait
Active through most of stance excel first 1-% (PF controlled by eccentric DF)
10% to heel off
- eccentrically controls ankle DF
- prevents excessive DF and knee flex
Major burst near heel off then decrease rapidly to toe off
-creates PF torque +forward propulsion = push off
