Kinetics (sagittal)

Question 1

Initial contact

Answer 1

Ankle - GFR posterior, concentric, tibialis anterior

Knee - GFR anterior; knee extension, concentric quads, eccentric hamstrings.

Hip - GFR anterior, flexion of the hip, eccentric gluteus maximus

Question 2

Loading response

Answer 2

Ankle - GRF posterior; plantarflexion - eccentric tibialis anterior
knee - GFR posterior; flexion - quads eccentric contracts
Hip - GFR anterior; flexion- gluteus maximus eccentrically contracts

**to stabilise hip and prevent anterior pelvic tilt)

Question 3

Midstance

Answer 3

Ankle - GFR anterior; dorsiflexion - eccentric gastroc and soleus

Knee - GFR posterior - quads concentrically

Hip - GFR posterior; extension - gluteus maximus concentrically

Question 4

Terminal stance

Answer 4

Ankle - GFR anterior; dorsiflexion - eccentric gastroc and soleus

MTP /Hallux - flexor hallucis /digitorium longus eccentrically

Knee - GFR anterior - hamstrings eccentric

Hip - GFR posterior - tensor fascia latae eccentric

Question 5

Pre swing

Answer 5

Ankle - initial GRF anterior; dorsiflexion - soleus and gastroc eccentrically
Then Achilles tendon recoils causing rapid plantar flexion with soleus and gastroc concentrically contracting (not important but bonus points)

Knee - GFR posterior - flexion, rectum femoris eccentric

Hip - GFR posterior - rectus femoris concentrically contracting to bring the hip back to a neutral position

Question 6

Swing phase

Answer 6

Ankle -
Initial swing - tibialis anterior concentric
mid swing - tibialis anterior isometric
terminal swing - tibialis anterior concentric

knee -
initial swing - flexion, hamstrings concentric
mid swing - extension (due to gravity)
terminal swing - extension, quads concentrically, hamstrings eccentrically

hip -
initial swing - flexion, rectus femoris concentric
mid swing - muscle activity reduces as momentum carrys the leg
terminal swing - gleutus maximus and hamstrings eccentric