Final answer:
As walking speed increases, the time spent in double-limb support decreases.
Step-by-step explanation:
The influence of walking speed on time spent in double-limb support is that as speed increases, time decreases. When a person walks at a faster pace, they spend less time with both feet on the ground simultaneously. This is because the time spent in double-limb support is the time when both feet are in contact with the ground during the gait cycle, and as speed increases, the time in this phase decreases.