Hi Siebe,
This is the only English translation I could find. This is not the best, and only mentions the verse he explains the cause of the rock hitting the foot, in the last 4 lines at the bottom of the page.
https://www.ancient-buddhist-texts.net/Texts-and-Translations/Connection-with-Previous-Deeds/05-Pierced-by-a-Rock.htm
Relevant to your marathon question; In the Pubbakamma Pilotika Therapadana, the Buddha says how he insulted a Buddha in a previous birth and gives this as the reason why he had to undergo 6 years of suffering before he attained enlightenment. This is a decision he made but the suffering due to that decision was a result of a kamma.
However, this is not to say that everything is deterministic and/or determined by kamma. This is evident as the Buddha realised that putting the body through immense suffering was not the way forward and decided to let go of that approach. Likewise, the man running the marathon to raise money may later on realise that there is an easier, less painful way to raise money. Or better still that there is more permeant solution to all these illnesses and help people on that path.
Thanks for the Girimananda Sutta, sorry I may have just skipped this section.
The Buddha here is explaining the “adeenava” of the body. I wouldn’t translate “adeenava” as danger per say, but may be say something like the problems of the body, or the bad effects experienced by the body.
Then he lists down all the illnesses (problems) that a body can experience. These 8 reasons are listed together with commonly known diseases and also heat/cold, hunger/thirst etc. If we take kamma as a separate cause we will also have to take hunger as a separate cause and fever as a separate cause, which doesn’t make sense. So, I don’t think it is correct to take these 8 reasons separately but should rather consider all aspects on the list together, as problems afflicting the body.
So to your main question; could bodily pain be due to other causes than kamma-vipaka? Short answer; Yes.
But based on the sutta’s we can say that kamma-vipaka will be the primary cause, and that other 7 causes will also play a part. So kamma-vipaka may not be the only cause but there can be no bodily pain without any kamma-vipaka. There will be atleast, say 1%, due to kamma-vipaka. It also means that the primary cause may not be the most prominent, or at least the most visible for us.