The terrain, weather, if they are mentally prepared,
The most logical variables are probably stance and how good you warmup
The terrain, weather, if they are mentally prepared,
The terrain, weather, if they are mentally prepared,
The terrain, weather, if they are mentally prepared,
wind,runningblocks,proctice,naturalability
wind,runningblocks,proctice,naturalability
wind,runningblocks,proctice,naturalability
could be because of the weather, mood of the runner, sleep, or the food they ate that day
height tailwinds or headwinds.
density
angle, speed, water density
Yes, different surfaces can affect a runner's speed. Soft surfaces like grass or sand can slow down a runner due to increased resistance. Hard surfaces like pavement or track can be faster for running as they provide better energy return and responsiveness.