I am not sure i understand the question. but if it you are asking what i think you are the answer could be one o the following.
using protective gear, such as knee pads, helmet, and hang grips. having water bottle, knowing the directions to where you wish to go, and a reflective light on the back.
<span />
B. Red blood cells contain a protein that binds with oxygen.
If you monitor your practice run you can see how much your improved time wise.
