Define a gait cycle...

"A period of gait from first initial contact with one foot to the subsequent contact with the same foot."

"Made up of stance phase and swing phase." (60% stance phase, 40% swing phase)

"The stride equivalent to 2 steps."

NB: Of the 60% stance phase, 20% of that is spent in double support (2 periods of 10% - start/end of swing phase)