Week 10 (Running)

Question 1

Differences in spatiotemporal parameters in running compared to walking?

Answer 1

• Stance phase becomes smaller: 60 -> 40%
• Increased stride length and rate: length (1.5 -> 3m), stride rate (45-50 strides/min to 75-80 strides/min)
• Increased peak vertical GRF: 1.2 BW -> 2.5BW

Question 2

Pelvis kinematics in running compared to walking

Answer 2

• Pelvis obliquity: more obliquity in running
• Pelvis tilt: increased anterior tilt when running quickly
• Pelvis rotation: less pelvic rotation in running since it is a more vertical movement

Question 3

Hip kinematics in running compared to walking

Answer 3

• Hip flexion/extension: more hip flexion during stance and swing to get the foot out further in front (increase stride length and absorb GRF during running)
• Hip adduction/abduction: less movement compared to walking
• Hip rotation: more hip rotation during running

Question 4

Knee kinematics in running compared to walking

Answer 4

• Knee flexion/extension: knee needs to flex more to absorb GRF and increase stride length

Question 5

Ankle kinematics in running

Answer 5

Ankle dorsiflexion/plantar flexion

• More dorsiflexion at heel strike
• More plantar flexion at toe-off

Question 6

Muscle activity at initial contact

Answer 6

• Hip extensors activate to help pick up hips over foot
• Quadriceps eccentrically absorb GRF
• Tibialis anterior and gastrocnemius co-contract to stabilise during impact

Question 7

Muscle activity at end of swing

Answer 7

• Hip extensors pull leg back towards ground for impact to propel for next stride
• Hamstrings control knee motion at end of swing
• Quadriceps absorb impact
• Gastrocnemius prepares for impact
• Tibialis anterior makes sure foot doesn’t hit ground

Question 8

Joint powers at hip, knee and ankle during running

Answer 8

• Hip: generates energy in stance to pull body over foot
• Knee: absorbs energy initially then creates energy in second half of swing
• Ankle: generates a lot of power at toe-off

Question 9

Power generation when running

Answer 9

Hamstrings and glutes pull the body forward by actively extending the hip after swing -> quadriceps and triceps surae push the body forward by extending the knee and plantar flexing the ankle -> psoas tendon propels the body into swing by pulling the thigh forward using elastic recoil

Question 10

In running, efficiency of movement is achieved through

Answer 10

1. Bi-articular muscles acting as energy straps

2. Storage and release of elastic energy in tendons that act like springs