Overview One gait cycle is measured from heel-strike to heel-strike consists of login to view 8 more bullets Stride is the distance between consecutive inital contacts of the same foot with the ground Step is the distance between initial contacts of the alternating feet Stance Phase Initial contact (heel strike) definition login to view 1 more bullet muscular contractions login to view 3 more bullets Loading response (initial double limb support) marks the beginning of the initial double limb stance definition login to view 2 more bullets muscular contractions login to view 2 more bullets Mid-stance (single limb support) initial period of single leg support definition login to view 1 more bullet muscular contractions login to view 1 more bullet Terminal stance (single limb support) definition login to view 1 more bullet muscular contractions login to view 1 more bullet Pre-swing (second double limb support) is the start of the second double limb stance in the gait cycle definition login to view 1 more bullet muscular contractions login to view 1 more bullet Swing Phase Initial swing (toe off) start of single limb support for opposite limb definition login to view 1 more bullet muscular contractions login to view 1 more bullet Mid-swing (foot clearance) definition login to view 1 more bullet muscular contractions login to view 1 more bullet Terminal swing (tibia vertical) definition login to view 1 more bullet muscular contractions login to view 1 more bullet Variables Affected During Gait Cycle Pelvic rotation pelvis rotates 4 degrees medially (anteriorly) on swing side login to view 1 more bullet Pelvic tilt pelvis drops 4 degrees on swing side login to view 1 more bullet Knee flexion in stance early knee flexion (15 degrees) at heel strike login to view 2 more bullets Foot mechanisms ankle plantar flexion at heel strike and first part of stance FHL plantarflexes the great toe during push-off and is inactive during swing phase Knee mechanisms at midstance, the knee extends as the ankle plantar flexes and foot supinates restores leg to original length reduces fall of pelvis at opposite heel strike Lateral displacement of pelvis pelvis shifts over stance limb login to view 1 more bullet Center of gravity (COG) in standing position is 5cm anterior to S2 vertebral body vertical displacement login to view 3 more bullets horizontal displacement login to view 1 more bullet Muscle Activity Figure showing muscle activity through different phases of gait cycle