Gait
At what point(s) (in %) of the gait cycle does Double Leg Stance occur?
0-10%
50-60%
What is Newton's 2nd Law for angular motion?
What does the KAM tend to do?
THe largest sagittal plane ROM occurs at which lower limb joint? and how much?
Tibiofemoral joint (knee) - 60 degrees
Why does higher KAM values tend to cause greater risk for OA progression?
- more medial compartment loading therefore more risk of cartilage degeneration
How are STEP and STRIDE length impacted in a LEFT limb injury?
RIGHT step length reduced (minimize time on injured/ painful limb)
BOTH strides decreased from normal (L stride will = R stride tho)
What zone is a tendon in it is lengthened past it's physiological range but has not ruptured?
Plastic zone
Does the KAM tend to cause a more valgus-aligned or more varus-aligned knee in the frontal plane?
Varus
How much hip flexion is typical for limb advancement during the swing phase?
20-30 degrees
What is an indirect measure of tibiofemoral OA medial compartment involvement?
KAM
In analysis of gait, what plane(s) would you analyse the thorax and pelvis
Transverse and frontal
What type of anatomical lever has the muscle between the axis of rotation and resistance force?
3rd class
Most common in human body (ex: biceps during bicep curl)
What are 7 ways to Decrease the GRF to decrease KAM
(KAM = GRF x MA)
1. Decrease walking speed
2. Decrease body mass
3. Recommend client walk on softer surfaces
4. Soft sole shoes rather than high heels
5. Orthotics
6. Use a cane
7. Increase muscle strength
At what point of the gait cycle is maximal plantarflexion achieved?
Toe off, about 60% of gait cycle, Plantarflexion to ~20 degrees!
What causes hip flexion in the 2nd half of swing phase?
Forward momentum carrying on from toe-off (little to no new muscle activity)
Indirectly then, gastrocs + soleus
True or False - Elderly individuals spend longer in swing phase because they move more cautiously and have weaker push off
False, older individuals spend longer in STANCE due to shorter stride length. This is due to worse balance, cautious gait (+ reduced proprioception), joint stiffness (less hip flexion and extension), worse ankle mobility, weaker (dynamic stability, propulsion)
Define Kinematics
study of movement WITHOUT regard to the forces that cause that movement (the WHAT)
What are 6 ways to decrease the moment arm to decrease KAM
(KAM = GRF x MA)
1. Change alignment - increase stance width? change COM?
2. Use a valgus knee brace
3. Alignment surgery
4. Wedge insoles
5. Change foot position - toe out
6. Change trunk position - recommend leaning over?
Describe the pattern and what causes the pattern of the vertical GRF
Double hump pattern
1st peak = initial contact
valley = mid-stance (approximates magnitude of body weight)
2nd peak = push off/ terminal stance
If you see compensatory trendelenburg sign during an assessment, how does this change your client's COM?
F (COM) would be moved to the right, reducing it's moment arm, and reducing the moment of COM
What are the 4 challenges of gait?
1. maintaning an upright posture
2. maintaining equilibrium
3. control of foot trajectory and ground clearance
4. controlling motion of multiple body segments
~ 30% (mid stance) because body right on top of foot
You are performing a biomechanical gait assessment on your first practicum placement. You notice your client's knee quickly deviating laterally as he walks. What is this called and how does it change the moment arm for KAM?
Varus Thrust
Increases the MA for KAM
What muscle is activated in the calf at initial contact during the gait cycle? Is it concentrically or eccentrically activated?
Tibialis Anterior, eccentric
What is the Tremdelenberg test and compensatory Trendelenburg sign?
Test: Single leg stance
Trunk and upper body leans towards stance limb (to compensate for pelvic drop away from stance limb)