Discussion: Warm up

For me, the aims of warm up are to go through range of movements for the joints, prepare the muscles for activity, and also our cardiovascular system as well.

So it will really depend on your fitness because I can't do as much warm up as you could, or else I will just get too tired.

It really should expose your joints to the range of movement likely encountered in the activity, start the motor units to the muscle firing, and the heart going.

Some slow runs building up to the speed you expect to run, type intervals.
Some leg swings, sideway runs, skips, strides, etc to go through range of movement.
Really you need to change it a little for each event as you will need to have a little more speed in the intervals for sprint. And possibly be more warmed up from sprint as you want to be fired up ready to go. At least with the long, you can actually use the first leg to get going, while settling into the terrain.

You really only need to be warmed up enough so you don't get that tired feeling after you start ( when we don't warm up)
and can go straight into your 'second wind' type cadence from the word go.