Gait, Running Mechanics and Economy

What are the two general phase of walking

stance phase and swing phase

What is the stance phase

the marked leg is in contact with the ground

What is the swing phase

the marked leg is in the air

What are the 5 phase of the stance phase

heel strike, loading response, mid-stance, terminal stance, pre-swing

What are the 3 phases of the swing phase

toe-off, mid-swing, terminal swing

During the stance phase, which phases have double support

heel strike and pre-swing

During the stance phase, which phases have single support

loading response, mid-stance, terminal stance

During the swing phase are there any phases that have double support

no

During the swing phase, which phases have single support

toe-off, mid-swing, terminal swing

What is the definition of a step in gait mechanics

distance between each foot when walking

What is the definition of a stride in gait mechanics

distance from foot plant to same foot plant (right foot to right foot)

What is the definition of step width in gait mechanics

when looking top down, the distance from medial side of one foot to the other

What is the definition of a gait cycle

Heel Strike (0%) to Toe Off (100%)

What plane is the camera when analyzing kinematics during a gait cycle

sagittal plane to see the joint angles

At what age is a mature gait pattern achieved

3 years old

What characteristics of gait mechanics decrease with age

speed, step length, range of motion, swing phase, stance:swing ratio, base of support and lateral sway (can be caused by nerve damage)

What is the difference between running and walking

running has a float phase, and running never has a double contact phase

How many float phases are in one running cycle

two float phases

What is the stance phase called in running mechanics

support phase, marked leg on ground

What is the swing phase called in running mechanics

non-support phase, marked leg in the air

What two phases make up the Stance(Support phase)

Absorption and Propulsion

What Two phases make up the first float phase, swing (non-support phase) and second float phase

Initial Swing and Terminal Swing

What makes up the Absorption and Propulsion phases

Initial contact, midstance, and toe off

What makes up the initial swing and terminal swing phases

Toe off, Mid-swing, and initial contact

What causes a faster run

a greater stride length

What creates a longer stride length

a higher posterior force production

When stride frequency is equated during a race, what is the primary determinant of the race

stride length

What is the definition of stride length

How much ground is covered with each step

What is the definition of stride frequency

How fast a stride is completed

How many strides does it take for elite male sprinters to cover 100 m

45 strides

During Usain Bolts 9.58s 100m how many strides did it take him

41 strides

What dictates stride length

anterior-posterior force application

What is running economy

at a given speed how much oxygen is used/required

Two people are running the same speed, runner 1 has a running economy of 40, runner 2 has a running economy of 50, who wins the race

runner 1 because they require less oxygen at that speed

What is the main determinant of running economy

genetics

What are the subdivisons of genetics that determine running economy

metabolic efficiency, cardiorespiratory efficiency, training, biomechanical efficiency, neuromuscular efficiency

What affects Metabolic efficiency

core temperature, muscle fiber type, substrate utilization

What affects cardiorespiratory efficiency

VO2 max, heart rate, minute ventilation

What affects training

training history, training type, training phase, Quality:Quantity, Fatigue, Training surface

What affects biomechanical efficiency

anthropometrics, running style, kinematics, kinetics, flexibility

What affects neuromuscular efficiency

neural signaling, motor programming, force production, stiffness

What is an example of an anthropometric effect on running economy

the smaller the Achilles tendon moment arm, the better the running economy

What are the anthropometrics of Triceps Surae and Running performance

The shorter the muscle and longer the tendon, the greater the improvement in loading and return of elastic energy from the Achilles

How does a shorter triceps surae and longer tendon affect the center of mass of the leg

it shifts the mass of the leg towards the knee

How does the Center of mass of the leg (shank) affect the amount of force required to swing the leg

the closer the center of mass of the leg to the knee (center of rotation) the less force required from the hamstring to swing the leg

When looking at the effect of mass on VO2 max, does the amount of mass matter

no

What matters when it comes to mass’s affects on VO2 max

where it is located

Give an example of how mass location matters when talking about the affects on VO2 max

1 kg around the trunk only increases VO2 max at a given speed by 1%, 1 kg around the lower leg increases VO2 max by 10% at the same speed

Order the types of muscle contractions from lowest energetic cost to highest

Isometric<Eccentric<Concentric

Approximately how much elastic energy can the achilles tendon store and return during running

35% of energy during loading

Approximately how much elastic energy can the tendons in the arch of the foot (plantar fascia) store and return during running

17% of energy

What makes the nike vaporfly shoes a “super shoe”

carbon fiber plate in the sole acts as a plantar fascia on steroids

What % improvement in running economy was seen with the Nike Vaporlies

a 4% improvement

What joint in the foot is the site of energy loss during running

the metatarsal phalangeal joint

Why do the running economy improvements occur in the nike vaporflies

the plate stores and returns elastic energy every step

How do the shoes increase running velocity

decreases the shortening velocity of the triceps surae by increasing its moment arm