Can I only help for half a day or interrupt the shift in between?

Since we have to plan the race perfectly for everyone, this is unfortunately not possible. The shifts depend on the specified times of your registration (there are minor exceptions depending on the circumstances)
If it is not possible to be at the race location on time due to the distance or other circumstances or if the shift is to be ended earlier, this must be clarified with the volunteer coordinator beforehand.

The beginning of the shift is always safe. The end of the shift can also be earlier.
Depending on the position where you are assigned.