locomotion Flashcards
locomotion
=movement of the body
Walking- lower limb in contact with ground at all times
Running- periods where body is in space
Cycling- lower limbs don’t touch ground. Using mechanism of equipment and rotation of lower legs
gait cycle stages
broken down into 2 primary phases: stance and swing phases
stance= entire time that a foot is on the ground
swing= entire time that the foot is in the air
weight acceptance (0-12%)–> broken down into initial contact (first rocker) and loading response (knee flexes to absorb shock) = to stabilize the limb, absorb shock and preserve the progression of the body
single limb support (12-50%)–> midstance 12-31% (second rocker motion), terminal stance 31-50% (centre of mass advances in front of supporting foot, heel raises off ground. 3rd rocker)
swing phase (50-100%)–> objective is Foot clearance over the ground, Forward swing of the limb, Preparation of limb for stance. broken down into preswing 50-62% (foot is pushed and lifted off of the ground), initial swing 62-75% (the hip, knee, and ankle are flexed- begin advancement of the limb forward and create clearance of the foot over the ground
midswing 75-87% (limb advancement continues and the thigh reaches its peak advancement), terminal swing 87-100% (foot is positioned for initial foot contact to start the next gait cycle)
unilateral stance
links back to the swing phase of walking
-to stop the pelvis from dropping, there has to be a counter torque of equal weight from the head, torso and other leg
-to maintain a unilateral stance, the hip abductors have to generate 3x the body weight
-sidebending towards the stance leg is easier for counter torque to occur
-loading= ground reaction force & muscular contraction
-the primary weight bearing area is the superior portion of acetabulum- this accomodates ground reaction forces and muscular contraction
the pelvis
=a good example of force coupling mechanism. the pivot point is around the acetabular socket
structures affecting pivot point of force coupling–> abdominals (ant, sup), hip flexors (ant, inf), erector spinae, quadratus lumborum, lats (post, sup), hamstrings (post, inf)
-pelvis disperses weight equally
-pelvis absorbs and dissipates ground forces to help lumbar
-modified synovial joint (also fibrous)
-anteriorly L shaped to provide a stable structure
-ligaments stabilise sacrum onto ilia and lumbar
there is a functional relationship–> hip flexors anteriorly rotate when hamstrings and abdominal wall/ hamstrings posteriorly rotate pelvis when erector spinae are weak
stair gait
=involves swing and stance phases where forward progression of the body occurs by alternating lower extremity movements
the lower extremities balance and carry the rest of the body similar to level ground gait. knee extensor movement is greater than walking in both ascent and descent. ankle movement is similar to walking
stance phase (weight acceptance, pull up, forward continuance)
swing phase (foot clearance, foot placement)
patella
=increases the leverage available to quads
–> helps to provide max amount of torque during flexion (in flexion there’s patellofemoral joint compression)
is stabilised by the cruciate ligs
if patella isn’t sat correctly- femoral condyles and posterior surface will erode
dynamic q angle
=the relation of femur in relation to hip and knee
will change in relation to activity being done and what is occuring with joints (e.g. OA changes)
dysfunctional Q angle will cause locomotion issues–> imbalance of musculature, injury, bony abnormality etc
convex & concave
=related to shape of surfaces. concave= hollow, convex= rounded
meniscus= improves fit of joint–> helps maintain articular surface contact and joint congruity through ROM
roll & slide principle
=2 vectors of movement in all joints
some joints roll and slide in same direction- others in different directions
getting up from sitting (knee flexion- extension)–> tibia is fixed and quads bring femur to extension. tibia slides in same direction while femur rolls
sitting down (extenion-flexion)–> popliteus rotates tibia to unlock knee. tibia is fixed while femur rolls in opposite direction (slides anteriorly). hamstrings gradually contract whilst quads relax. cruciate ligs control the slide
screw home mechanism of knee
=stabilising mechanism for tibiofemoral joint during extension
requires 10 degrees of ext rot during last 30 degrees of extension (locking out knee)–> this maximises contact between femur and tibia and helps improve congruence and stability
popliteus unlocks the knee and then releases to produce extension
femur & patella mal-tracking (common exam question)
=miserable knee syndrome
where the patella doesn’t move smoothly between anteriorly condylar surface–> pulls in to one side causing erosion
could be caused by: dysplastic hip, laxity of periarticular tissues, short/ tight int rotators & hip adductors, coxa varus, genu valgum etc
significance of talus
=has no muscular attachments- is a point of contact between distal tibia, fibula & calcaneum–> acts as a torque converter (rotations of leg converts to inversion and eversion of foot) this helps adapt foot to ground reaction forces
locking of talus during toe off creates a stable base for weight bearing & propulsion
tibia and fibular movement on talus= sliding movement which is opposite to talus rolling on calcaneus
things that can go wrong:
adulthood–> parkinsons (shuffling), toe walking (cerebral palsy), antalgic (pain, disc herniation), stamping (loss of sensation) etc
childhood–> DDH, slipped capital femoral head, perthe’s (hip), sever’s (ankle), osteomyelitis tumour
form and force closure
=uses the shape of one bone in relation to bones to provide stability to the surrounding joints
For mobility to occur further joint compression and stabilisation is required to withstand a vertical load.
Force closure is the term used to describe the other forces such as the ligaments and muscles acting across the joint to create stability.
Examples of this mechanism are the SIJ, talus and cuboid of the ankle and foot.
force coupling
=2 opposing forces rotating around a pivot point.
There are multiple forces at any given moment. These can be equal or unequal, depending on the function required and balance of moving elements such as muscles and balance of stabilising elements such as ligaments.
An example of force coupling around a pivot point is the balance of position of the pelvis around S2 and the hip joint. Excessive contraction of Psoas muscle will lead to an anterior rotation of pelvis, excessive contraction of the hamstring group will lead to a posterior rotation of the pelvis.
Another example of Force coupling is the scapula-humeral rhythm.
gait cycle determinants
pelvic rotation, pelvic tilt, knee flexion at mid-stance, foot and ankle motion, knee motion and lateral pelvic displacement
