Biomechanical Analysis final

what are the phases of running?

1. stance: weight acceptance and propulsion (triple extension)

2. early float (flight): this is the main difference between running and walking which causes there to be no double limb support in running

3. swing: swing limb advancement (triple flexion)

4. late float (flight)

how much running time is spent in float?

30%

discuss weight accpetance during running

• same as walking

• GRFs are larger

• large increase in muscular demand and stability

discuss triple extension (propulsion) during running

• hip extension, knee extension, and anke PF

• important to give us more force to get off the foot and get in flight to then prepare well for our foot to touch the ground again

• training in multijoint movements here is important so jumping/plyo and power training

discuss triple flexion (swing) during running

• hip flexion, knee flexion, ankle DF

• need to be able to clear the limb quickly so its in a good spot for weight acceptance so going to need more muscular usage here than walking

• train with box jumps, hurdle training, high knees, etc

what are the main differences between walking and running gait?

more coordination, force, ROM, energy are required for running. NO double limb support in running

what are the mobility features of competitive runners compared to novice runners?

• increased flexion ROM of the knee in swing

• decreased ROM of hip and ankle in all planes

• these allow for more efficiency to clear the ground and keep moving forward

what are the force features of competitive runners compared to novice runners?

• increased strength of hips and trunk

• increased used of elastic energy so they are more bouncy and yet stiff enough to store the energy to go far without having to spend a lot of time in stance

what are the sensorimotor features of competitive runners compared to novice runners?

• decreased spatiotemporal variance so they are consistent in their strides

• increased limb symmetry

• increased alignment with COM and initial contact. their COM is directly on top of initial contact so theres less GRFs coming back at them so they don’t have to use as much energy to keep moving forward

what are the energy features of competitive runners compared to novice runners?

• increased muscular endurance

• increased aerobic endurance

what occurs when we change speed when running?

everytime our foot hits the ground it can either slow us down, keep the speed or make us go faster by…

• deceleration— braking is greater than propulation

• maintenance— braking and propulsion are equal

• acceleration— braking is less than propulsion. requires a better use of triple extension, footwear, arm swing and trunk rotation, running efficiency, and COM in front of foot with forward trunk lean

what are the spatiotemporal changes relative to speed when running?

• step length and frequency both increase as speed increases

• as speed increases, stance time decreases and flight initially increases but then decreases.

• decreased duty factor meaning that the ration of stance time and flight time becomes smaller

• as speed increases, vertical COM displacement initially increases but then decreases

what makes for good running performance?

big steps + fast steps + efficient use of energy (most limiting factor)

what does it mean when a runner is bouncy?

• short stance time

• long flight time

• generatin of larger forces

• con: high vertical displacement which is exacerbated when running at low speeds. therefore, this is not best for endurance athletes

what does it mean when a runner sticks?

• cons: short flight time and long stance time which are not good for speed

• low vertical COM displacement

• beneficial for uneven terrain

• beneficial for increased load like when running while carrying something

what does it mean when a runner hops?

• high step frequency

• decreased mobility needs meaning they can take smaller steps and yet keep running

• cons: high vertical COM displacement and low propulsion so they dont use elastic energy well

what does it mean when a runner pushes?

• decreased peak force so they use less power and more raw strength

• long stance time and step length so force is spread over a longer amount of time so it’s less demanding

• prolonged propulsion

• low vertical COM displacement

• con: lower step frequency so dont go as fast

what does it mean when a runner sits?

• this is not a good running strategy and is often seen with fatigue or lack of coordination

• cons: COM more posterior to foot at initial contact which causes increased posterior GRFs and then increased propulsion demand on LE muscles

• deceleration position which puts decreased braking demand on LE muscles

forefoot running puts increased demand on what?

PFs, distal hamstrings, foot and ankle stabalizing muscles

what are the associated pathologies that would cause forefoot running?

• plantar fasciitis

• achilles tendinopathy

• posterior tibialis tendinopathy

• distal hamstring tendinopathy

rearfoot running puts increased demand on what?

quadriceps, calcaneus, tibiofemoral joint, hip extensors, DFs

what are the associated pathologies that would cause rearfoot running?

• gluteal tendinopathy

• proximal hamstring tendinopathy

• knee OA

• tibial stress syndrome

• anterior knee pain syndrome

when considering different populations, what are the two routes we could go when thinking of interventions?

1. restore funtion to normalize gait

2. compensatory function to compensate for abnormal gait— used for those who have something that can’t get better or will take a while

in regards to the ICF model, when may we choose to use restoring function vs compensatory function interventions?

if someone has a limitation in activities or participation, we can use the compensatory measures to help improve these areas while they are improving on the impairment that may take some time

what are the influences on intervention selection?

health conditions, personal factors, and environemental factors

within the different practice areas of PT, what are some conditions that we may need to use compensatory function for?

• ortho: OA

• sports: in season athletes

• older adults: comorbities or dementia

• neurology: SC injury

• peds: developmental or congenital disorders

• CF and pulmonary: HF and arrhythmias

• wound management: gangrene/infection, open wounds, those with amputations

• womens health: pregnancy or menopause

what are the parts of the 4 element model?

motion: ability of a joint/tissue to move passively

force: ability of a tissue to produce movement and dynamic stability

motor control: ability to plan, execute, and adapt goal directed movements

energy: the ability to perform sustained/repeated movement and is dependent of the CVP, pulmonary, and NM systems

what are the steps of the 4 element movement system model?

1. observe the movement using CASSS

2. formulate a hypothesis

3. determine tests and measures

4. evaluation and interventions

what does CASSS stand for?

Control: smoothness, coordination, stability, sequencing, timing initiation

Amount of movement: amplitude, excursion, ROM of movement required to complete the activity

Speed of movement: time to complete the task

Symmetry of movement: there may be natural assymmetries in a task

Symptom provocation: guarded, SOB, pain, incontinence